Post-vaccine surveillance of Group A Rotavirus Strains circulating in the Littoral and South West Regions of Cameroon

Post-vaccine surveillance of Group A Rotavirus Strains circulating in the Littoral and South West Regions of Cameroon | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Post-vaccine surveillance of Group A Rotavirus Strains circulating in the Littoral and South West Regions of Cameroon Carine Ngah Enjeh, Rahinatou N. Ghapoutsa, Maurice Boda, Mathew D. Esona, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8198863/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 12 You are reading this latest preprint version Abstract Background: The effectiveness of Group A Rotavirus (RVA) vaccine in low-income countries has been limited, partly due to the circulation of strains not covered by existing vaccines. Despite the introduction of Rotarix (2014) in Cameroon, no nationwide studies have characterized circulating RVA strains. This study provides post-vaccination of RVA genotyping data from the Douala, Edea, Nkongsamba (Littoral) and Kumba (Southwest) regions of Cameroon. Methods: A cross-sectional study was carried out on 197 diarrheal samples and vaccination data collected from children under five from the Littoral region (n = 130; May 2015 - April 2016) and Kumba Southwest (n = 67; July 2017 - June 2018). RVA NSP3 gene was detected using qRT-PCR and the NSP3-positive samples underwent one-step multiplex RT-PCR for genotyping wild-type and vaccine strains, with VP4 and VP7 typing performed via nested PCR. Results: Of the 197 children, 63% were fully vaccinated with Rotarix, 22% were unvaccinated, and 15% had unknown status. A total of 87 samples were successfully genotyped (28 from Littoral, 59 from Kumba). Five VP7 (G) genotypes were identified: G1, G2, G3, G9, and G12. In Littoral, G2 (46.4%) and G3 (35.7%) predominated, while G1 (61%) and G12 (37.3%) were most common in Kumba. VP4 (P) genotypes included P[ 8 ], P[ 6 ], and P[ 4 ], with P[ 8 ] being most frequent in both regions. Mixed infections (3.6%) and non-typeable strains (7.1%) were also observed. Dominant G-P combinations included G3P[ 8 ] and G2P[ 4 ] in Littoral, and G1P[ 8 ] and G12P[ 6 ] in Kumba. Rare and partially typed strains were also detected. Conclusion: This study highlights the predominance of G1P [ 8 ] in vaccinated children and the emergence of non-vaccine-covered strains such as G2P [ 4 ], G3P [ 6 ], and G12P[ 6 ]. These findings underscore the need for ongoing surveillance and potential vaccine adjustments. /Concepts: Rotavirus RT-PCR Genotype Circulating Strains Rotarix Littoral Kumba Cameroon Figures Figure 1 INTRODUCTION Rotavirus group A (RVA) is a leading etiological agent of severe diarrhea in infants and young children under five years of age, accounting for an estimated 128,500 deaths annually worldwide [ 1 ]. The disease burden is disproportionately high in sub-Saharan Africa, where RVA remains one of a major cause of hospitalizations for acute gastroenteritis in children, resulting in substantial medical and socioeconomic impacts [ 2 , 3 ]. In Cameroon, RV accounts for more than 5800 deaths yearly among children under 5 years of age in Cameroon and accounted for 33 to 38.1% of diarrhea-related hospitalizations in this age group [ 4 , 5 ]. To reduce the global disease burden, four oral vaccines, RotaTeq, Rotarix®, ROTAVAC, and Rotasiil, have been approved and recommended by World Health Organization (WHO). These vaccines have been incorporated into routine immunization programs in over one hundred (100) countries. Post vaccine surveillance in some of these countries have revealed a significant reduction in RVA-associated morbidity and mortality globally [ 6 ]. Prior to the introduction of rotavirus vaccine Douala, Edea, Nkongsamba (littoral) and Kumba (Southwest) in Cameroon, RVA surveillance was primarily driven by independent research initiatives. In 2007, a collaborative effort between the U.S (Centers for Disease Control and Prevention, CDC-Atlanta) and the Cameroon Ministry of Health, under the Surveillance Strengthening Project in Central Africa (SURVAC), established a national framework for RVA surveillance. Data collected during the pre-vaccine era revealed considerable genotype diversity and temporal variation across regions. For instance, Esona et al. (2010) identified G1P[ 8 ] as the predominant strain in Western Cameroon during the 1999–2000 rotavirus season [ 7 ], while G9P[ 8 ] predominated in Yaoundé (the Central region of Cameroon) during 2008–2010 [ 8 ]. Ndze et al. (2011) later reported the emergence of G12 as the most prevalent genotype in the Far North and Northwest regions during 2010–2011 [ 9 ]. This epidemiological background informed the adoption of Rotarix® into Cameroon’s Expanded Vaccination Program (EPI) on March 28, 2014 [ 4 ]. Despite, WHO recommended surveillance programmes at sentinel sites across Africa to monitor the burden of rotavirus disease and circulating strains before and after vaccine introduction as one of the crucial tools in measuring the impact of rotavirus vaccines [ 10 ], Cameroon unlike some African countries has paucity in post-vaccine circulating RV strains. This study therefore aims to characterize the genotypic diversity of RVA strains circulating in the Littoral and Southwest regions of Cameroon during the post-vaccine introduction period. Rotavirus gastroenteritis in humans is associated with mainly six genotype combinations ; G1P[ 8 ], G2P[ 4 ], G3P[ 8 ], G4P[ 8 ], G9P [ 8 ] and G12P[ 8 ], causing majority of infections [ 11 ]. Although the distribution of these six globally important rotavirus genotypes can change dramatically in regions from year to year, the G1P[ 8 ] rotavirus strain has remained the most prevalent strain worldwide [ 12 – 14 ]. However, significant diversity of rotavirus genotypes continues to be observed worldwide with several novel combinations due to accumulation of point mutations, genome re-assortments, and/or zoonotic transmission to human host resulting in the introduction of new antigenic variants across regions [ 15 , 16 ]. Confronted with the genetic diversity of RVA and the potential for regional genotype shifts, continuous molecular surveillance is critical to monitor the circulating post-vaccine strain. Such data are essential for evaluating vaccine effectiveness, guiding public health policy, and informing future vaccine development. METHODS Ethical and administrative considerations Prior to initiating this study, ethical approval was obtained from the Cameroon National Ethics Committee (Approval Nos. 2016/01/696/CNERSH/SP and 2017/06/923/CE/CNERSH/SP). Research authorization was also granted by the Littoral and Southwest Regional Delegations of Public Health (Authorization No. 1684/AR/MINSANTE/DRSPL/BCASS). Written informed consent was obtained from a parent or legal guardian of each participating child. The study protocol adhered to the principles outlined in the Declaration of Helsinki (1975) and was endorsed by the Ministry of Public Health of Cameroon. Study population, period and sample collection This cross-sectional study was conducted in two phases: from May 2015 to April 2016 in the Littoral region, and from July 2017 to June 2018 in Kumba, Southwest region of Cameroon. Diarrheal stool samples were collected from children under five years of age presenting at the pediatric departments of the following health facilities: Littoral Region: Laquintinie Hospital, Bonassama District Hospital, Deido District Hospital, Edéa Regional Hospital, and Nkongsamba Regional Hospital. South-west Region: Kumba District Hospital, Baptist Health Centre, Ekona District Hospital, and Bambini Pediatric Foundation. Children with bloody diarrhea or aged over five years were excluded. For each enrolled child, demographic and clinical data - including vaccination status and breastfeeding history - were obtained from medical records and/or guardians. All stool samples were transported in cool boxes (maintained at 4–8°C) to the Virology Laboratory of the Mother and Child Center of the Chantal Biya Foundation and the Military Health Research Center (CRESAR), Yaoundé, following standard biosafety protocols. Stool processing and nucleic acid extraction A 10% (v/v) stool suspension was prepared in nuclease-free distilled water (Invitrogen™) for RNA extraction. Samples were stored at − 20°C until processing. Total RNA was extracted manually using the QIAamp® Viral RNA Mini Kit (Qiagen, Hilden, Germany) according to the manufacturer’s protocol. The RNA extracts were subsequently stored at − 80°C until use. As an internal process control, 2 µL of MS2 bacteriophage RNA (10⁹ units/µL; ZeptoMetrix, Buffalo, NY, USA) was spiked into 48 µL or 98 µL of each stool suspension prior to extraction. All samples and reagents were equilibrated to room temperature before use. RVA NSP3 gene detection by qRT-PCR Detection of the RVA NSP3 gene was performed by qRT-PCR (Qiagen, Inc. Valencia, CA) following the manufacturer's instructions. Genetic Typing of RVA Samples positive for the rotavirus NSP3 gene underwent further genotyping using both multiplex real-time RT-PCR and nested RT-PCR approaches. The multiplex real-time RT-PCR assay targeted specific markers in the VP7 and VP4 genes to simultaneously detect wild-type and vaccine strains (Rotarix® and RotaTeq®), while including MS2 RNA as an internal control [ 17 ]. The assay covered the following genotypes: G1, G2, G3, G4, G9, G12, P[ 4 ], P[ 6 ], P[ 8 ], as well as vaccine strains. Nested RT-PCR was also performed for VP7 and VP4 genotyping. This involved two rounds of conventional RT-PCR using genotype-specific primer sets, with the second round using the amplicon from the first reaction as the template. Amplicons were analyzed by agarose gel electrophoresis to determine the genotype [ 18 ] RESULTS - Demographic characteristics Diarrheic stool samples were collected from 197 children of both gender with age ranging from 0–59 months, consulting or hospitalized for severe diarrhea in the Littoral region and South west region (Kumba) of Cameroon. - Vaccination status Out of the total sample collected, 63% (124/197) of these children had received both doses of Rotarix vaccine, while only 22% (43/197) were unvaccinated and 15% (30/197) had unknown vaccination status. - Regional distribution of Genotypes Out of the 197 samples collected, 87 were genotyped with 28 from the Littoral region and 59 from Kumba South West Region of Cameroon. The individual P and G genotypes per area of study is represented on Table 1 below; Table 1 Circulating P and G genotypes in Littoral region and Kumba, South West region of Cameroon Genotypes Littoral Region Number and (%) Kumba SWR Number and (%) G genotypes G1 4 (14.3%) 36 (61%) G2 13 (46.4%) 0 G3 10 (35.7%) 0 G9 1 (3.6%) 0 G12 0 22 (37.3%) GNT 0 1 (1.7%) P genotypes P[ 4 ] 5 (17.9%) 0 P[ 4 ]P[ 8 ] 1 (3.6%) 0 P[ 6 ] 6 (21.4%) 22 (37.3%) P[ 8 ] 14 (50.0%) 37 (62.7%) P[NT] 2 (7.1%) 0 Where NT = non-typed Circulating VP7 genotypes The 87 samples characterized for G-specificity reveals 5 different RV VP7 genotypes including G1, G2, G3, G9, G12. G1 was characterized in both study area and most predominant in Kumba (61%) and third predominant (14.3%) in the Littoral region of Cameroon. G2 was the most predominant VP7 genotypes in the Littoral region (46.4%) although not fouind circulating in Kumba. The second predominant G-genotype in the Littoral region was G3 (35.7%) followed by G9 (3.6%) although both G3 and G9 were not found circulating in Kumba. The G12 (37.3%) genotype was second predominant in kumba. 1% of the G-type was not typeable. Circulating VP4 genotypes A total of 87 samples were characterized for P specificity from both area of study. 3 different VP4 genotypes were characterized including P [ 4 ], P [ 6 ] and P [ 8 ]. P [[ 8 ] was the most predominant in Kumba and Littoral regions with respective percentages of 62.7% and 50% respectively. P [ 6 ] was the second predominant in both regions with percentages of 37.3% in Kumba and 21.4% in the Littoral region. P [ 4 ] was found circulating only in the Littoral region at 17.9% Mixed infections were observed at 3.6%, whereas 7.1% of the strains were non-typeable as seen on Table 1 above. Genotype distribution in Littoral region and Kumba Table 2 Distribution of Genotypes in Littoral and Kumba Genotype Combinations Littoral Region Frequency/ Percentages Kumba (SWR) Frequency/ Percentages G1P [ 8 ] 4 (14.3%) 34 (57.6%) G1P [ 6 ] 0 2 (3.4%) G2P [ 4 ] 5 (17.9%) 0 G2P[ 4 ]P[ 4 ]P[ 8 ] 1 (3.6%) 0 G2P[ 6 ] 2 (7.1%) 0 G2P[ 8 ] 3 (10.7%) 0 G2P[NT] 2 (7.1%) 0 G3P[ 6 ] 4 (14.3%) 0 G3P[ 8 ] 6 (21.4%) 0 G9P[ 8 ] 1 (3.6) 0 G12P[ 6 ] 0 19 (32.8%) G12P[ 8 ] 0 3 (5.1%) GNTP[ 6 ] 0 1 (1.7%) TOTAL 28 59 Where nt = non-typed Distribution of genotypes in Littoral region From the 130 samples collected in the Littoral region, 28 were successfully genotyped as seen on Table 2 above. G3P[ 8 ] and G2P[ 4 ] were the most predominant (with respective percentages of 21.4% and 17.9%), followed by G1P[ 8 ] (14.3%), G3P[ 6 ] (14.3%), G2P[ 8 ] (10.7%), G2P[ 6 ] (7.1%) and G9P[ 8 ] (3.6%). The presence of a rare combination, G2P[ 4 ]P[ 8 ] (3.6%) as well as partially determined genotypic combinations G2P[nt] (7.1%) were identified. Distribution of genotypes in Kumba, South West Region Of the 59/67 genotyped samples from this region, the most common genotype combination was G1P[ 8 ] (57.6%), followed by G12[P6] (32.8%). While the least common genotype combinations were G12P[ 8 ] (5.1%) and G1P[ 6 ] (3.4%). A partially determined genotypic combinations GntP[ 6 ] (1.7%) (Table 2 ). Post-vaccinal distribution of RVA Genotypes in Littoral Region and in Kumba, South West Regions of Cameroon (2015–2018). A total of 87 samples were genotyped in both area of study revealing the most common genotype combination to be G1P [ 8 ] (44%), followed by G12 P[ 6 ] (22%). The least common genotype combinations were G3P[ 8 ] (7%), G2P[ 4 ] (6%), G3P[ 6 ] (5%), G2P[ 8 ] (4%), G12P[ 8 ] (3%), G1P[ 6 ] (2%), G2P[ 6 ] (2%) and 1% of G9P[ 8 ], with the presence of a rare combination, G2P[ 4 ]P[ 8 ] (1%)as well as partially determined genotypic combinations G2P[NT] (2%) and GNT P[ 6 ] (Fig. 1). DISCUSSION Although Cameroon has actively participated in the WHO surveillance programme and introduced the monovalent Rotavirus vaccine (Rotarix, GSK) in March 2014 into the EPI program of Cameroon, there is no available molecular data and information on circulating strains of RVA in the country. This present study aims at characterizing circulating post vaccinal RVA genotypes in Littoral and South West Region (Kumba) of Cameroon. This post vaccinal study reveals strains carrying G1 (61%) and G12 (37.3%) genotypes as the most common VP7 genotpes in Kumba usually found in combinations of P[ 8 ] and P[ 6 ] VP6 genotypes. Most of the common genotypes identified in the Littoral region were (G2, G3, G1) usually found in combinations with P[ 8 ], P[ 6 ] and P[ 4 ] VP4 genotypes (Tables 1 and 2 ) In contrast to the G1 genotype which remained the most predominant in the pre and post vaccinal era in Kumba, the G2 strain although not found circulating in Kumba was the most predominant VP7 genotype isolated in the littoral region. The predominance of the G2 genotype was also noted after the introduction of the vaccine in Malawi [ 19 ]. The presence of G1 genotype in Kumba was observed at a lower prevalence compared to pre-vaccinal era. This lower prevalence might be due to the emergence of other genotypes such as G12 identified as the second predominant in this post vaccinal era in Kumba accounting for 37.3% circulating G genotypes in Kumba. Although the G12 was not found circulating in the pre-vaccinal era in Kumba, it has been long time found circulating in the pre-vaccinal era in Northern Cameroon [ 20 ]. The P [ 8 ] genotype was the most predominant in both area of study in the pre and post vaccinal era in Cameroon followed by P [ 6 ] genotype in the pre-vaccinal era, remained the most predominant even after the introduction of Rotarix in Littoral and Kumba with respective percentages of 50% and 62.7%. The P [ 6 ] genotype being the second predominant is thought to infect animal species [ 21 ] and accounts for one third of P genotypes reported in other studies in Africa [ 22 ]. After the introduction of RVA vaccines in African countries, P [ 6 ] is increasingly detected across the continent [ 23 ], a fact that our results appear to support. The high prevalence of genotypes with high zoonotic potential, G3 and P[ 6 ], may be linked to the domestic breeding of cattle, dogs and pigs in Africa [ 24 ]. Globally, the predominant genotypic combinations are G1P[ 8 ], G2P[ 4 ], G3P[ 8 ], G4P[ 8 ] and G9P[ 8 ] [ 12 , 14 ]. This study reveals G3P[ 8 ], G2P[ 4 ], G3P[ 6 ] and G1P[ 8 ] genotypes to be the majority in the Littoral region representing 67.9% of RVA infections. However, G3P[ 8 ] (21.4%) was the most isolated genotypic combination in the littoral region unlike globally and other studies carried out in Cameroon before the introduction of the vaccine. Several countries reported G3 in combination with P[ 8 ] during the 12th African Rotavirus Symposium 2019 [ 25 – 27 ]: Botswana reported an outbreak of G3P[ 8 ] in 2018 [ 28 ], Malawi (introduced vaccine in 2012, reported G3P[ 8 ] in 2018), Kingdom of Eswatini (introduced vaccine in 2015, reported G3P[ 8 ] in 2018). Around the world, the emergence of genotype G3P[ 8 ] and equine-like G3P[ 8 ] in 2013 in Australia and re-emergence of G3P[ 8 ] were observed in Brazil in the post-vaccine introduction [ 29 – 31 ]. This could be linked to its antigenic composition different from that of the vaccine which would allow it to escape immune pressure in particular from vaccines since this strain was taken into account in the design and testing of the Rotarix vaccine [ 32 ]. The G1P[ 8 ] genotype combination was the most predominant in Kumba during this study period, accounting for 57.6% RVA infection in this region. The predominant and sustained circulation of G1P[ 8 ] strains was observed several years in a row, before the introduction of the vaccine, particularly in the studies of Esona and collaborators, where 37.1% of G1P[ 8 ] strains was recorded; then in the study by Boula and his team where 44% of G1P[ 8 ] was noted. This strain is also predominant in the Central African Republic where 37% of G1P[ 8 ] strains have been reported [ 7 , 8 , 20 , 33 ]. Although the G1P[ 8 ] strain showed its predominance in Kumba after vaccine introduction, it had a low appearance rate (14.3%) in the Littoral region. This study also confirms the emergence of the G2P[ 4 ] (17.9%) and G3P[ 6 ] (14.3%) strains in the littoral region and G12 P[ 6 ] (32.8%) and G12 P[ 8 ] (5.1%) in Kumba which have become globally important. The prevalence of G2P[ 4 ] obtained in this study was higher than any observed in Cameroon in the past [ 8 , 20 ]. A similar result was registered in Belgium and Brazil after the exclusive use of the monovalent Rotarix vaccine which led to an increase in G2P[ 4 ] strain [ 32 , 34 ]. The sudden appearance of G12P[ 8 ] rotavirus strains soon after the introduction of rotavirus vaccines in Kumba is quite interesting. During the pre-vaccinal study in Cameroon, the G12P[ 8 ] strain was mainly isolated in Bamenda and Maroua [ 20 ] and WHO African Rotavirus surveillance programme showed the emergence of G12 strains as the dominant strain in Nigeria and Senegal, countries that had not yet introduced rotavirus vaccines in their immunization programme. Therefore, the observed emergence of G12 strains post-vaccine introduction may not be associated with vaccine introduction and may represent natural secular variation in rotavirus strains. The identification of the mixed genotype P[ 4 ]P[ 8 ] in the Littoral region highlights reassortment events originating from co-circulating local strains. Complete genome sequencing of the strains would be necessary for in-depth characterization and determination of the degree of natural reassortment. The presence of indeterminate P (P[nt]) and G (Gnt) genotype in Littoral and Kumba respectively, is not a common issue but has been often observed in low-income countries [ 12 ]. Thus, Esona and his team in 2010 demonstrated that the majority of non-typable tensions encountered in Africa can be genotyped, with the use of specific primers or improve genotyping techniques [ 7 ]. In this study, it is possible that some of the rare RVA genotypes were present among the non-typeable strains. To confirm this, further research needs to be done using more specific primers that will allow genotype of rare strains or new strains. The presence of the G1 or P [ 8 ] strains among vaccinated children who have received both doses of the Rotarix vaccine in this study reveals vaccination status does not prevent the occurrence of RVA infection in vaccinated or unvaccinated children. The G1 P[ 8 ] strain was seen at its peak in kumba although with lower appearance rate (14.3%) in the littoral region but with a rise in other genotype combinations (G3P[ 8 ], G3P[ 6 ], G2P[ 8 ], G2P[ 6 ]). Countries that introduced the monovalent Rotarix® vaccine similar to Cameroon, reported similar results with a decline of the genotype combination G1P[ 8 ] with a concurrent rise in other combinations in the post-vaccine period. For example, South Africa reported an increase in non-G1P[ 8 ] strains [ 35 ], in contrast to Malawi where the reduction of G1P[ 8 ] was not significant [ 36 ]. In Ghana, G1P[ 8 ] returned as one of the dominant strains in the fourth year post-vaccine introduction [ 37 ]. Other studies reported from England, Brazil, Belgium, Scotland, a decline in the proportion of G1P[ 8 ] with a rise in the proportion of heterotypic strains, such as G2P[ 4 ], was observed [ 38 , 39 ]. The presence of the G2P[ 4 ], G3P[ 6 ], G2P[ 6 ] and G12 P[ 6 ] strains isolated from children who received a full dose of Rotarix in both area of study reports lower vaccine effectiveness against strains that do not share any G and/or P specific genotype with Rotarix voltages (G1P[ 8 ]). This hypothesis is in agreement with studies that were carried out during mass vaccination with the Rotarix vaccine, notably in Latin America, Australia and Europe where G2P [ 4 ] dominated other strains over several RVA seasons [ 40 ]. Additionally, Belgium reported a slightly lower vaccine effectiveness against G2P[ 4 ], and in Malawi, a lower vaccine effectiveness against G2 strains than G1 strains was reported [ 41 ]. However, experts believe that the possibility of high reappearance of G2P [ 4 ] in the Littoral region could be the result of the natural variation of Rotavirus strains [ 16 ]. In other words, these children who had received a full dose of Rotarix were instead protected against strains having a combination with one of the genotypes found in the vaccine but might be vulnerable to other genotypes, although recent theories suggest that vaccine failure cannot be a direct consequence of the circulation of rare strains of RVA in African countries [ 42 ]. This could be explained by the fact that these strains share sequences different from those of the vaccine strain. Conclusion This is the first Rotavirus post-vaccinal report describing the circulation of Rotavirus genotypes in two study areas in Cameroon. The results obtained highlights the predominance of G1P [ 8 ] and showed a shift in circulating genotypes following vaccine introduction. In addition, the emergence of unusual strains, such as G2P [ 4 ], G3P [ 6 ] and G12P[ 6 ] not under the vaccine coverage was also observed, which underscore the need for continued country-wide surveillance to monitor changes, due to possible vaccine pressure, and consequently, the effect on vaccine effectiveness. Limitations The limitations of this study are due to the fact that the period of sample collection from the area of study was different. In the Littoral region, the samples were collected from May 2015 - April 2016 and in Kumba, sample collection was from July 2017-June 2018. Abreviations CDC : Center for Diseases control and prevention; ELISA : Enzyme linked immunosorbent assay; EPI : Expanded program on immunization; NSP : Non-structural protein; qRT-PCR : Quantitative reverse transcription-polymerase chain reaction; RNA : Ribonucleic acid; RT-PCR : Reverse transcriptase-polymerase chain reaction; RVA : Group a rotavirus; SURVAC : Surveillance Strengthening Project in Central Africa VP : Viral protein; WHO : World Health Organization Abbreviations CDC : Center for Diseases control and prevention; ELISA : Enzyme linked immunosorbent assay; EPI : Expanded program on immunization; NSP: Non-structural protein; qRT-PCR : Quantitative reverse transcription-polymerase chain reaction; RNA : Ribonucleic acid; RT-PCR : Reverse transcriptase-polymerase chain reaction; RVA : Group a rotavirus; SURVAC : Surveillance Strengthening Project in Central Africa VP: Viral protein; WHO : World Health Organization Declarations Acknowledgments We express our gratitude to Dr. Mathew Dr. ESONAof the Department of Virology (Sefako Makgatho Health Sciences University Pretoria, South Africa) and Dr. BODA Maurice for ensuring the supplies of all what was needed to ensure the success of this research. The Chief of Centre and Staff of the Military Health Research Centre (CRESAR), Yaoundé for supervision and technical support, the children and their parents who participated in this study and the pediatric services of the Laquintinie hospital, the district hospitals of Bonassama and Deido, the regional hospitals of Edéa and Nkongsamba all of the littoral region and the pediatric services of Kumba District Hospital, the Baptist Health Centre, the Ekona District Hospital and Bambini Pediatric Foundation of the South West Region. Authors’ contributions Bench and data analysis: CNE, RNG, MB, MDE . Reagents/materials and analysis tools: MDE, JMN, MB. Manuscript preparation: CNE, RNG, PMN, MB, MDE. Study designed: MB, MDE, PMN, MAN, JMN. Field work activities: CNE, RNG, MB, PMN, LNN. Laboratory work: CNE, RNG, MB, MDE, JMN, VNN. Supervision: MAN, MB, PMN, JMN, MDE, MDB. All the authors read and approved the final manuscript. Funding This study was supported by the personal funds of the authors. Availability of data and materials The datasets used and analyzed during the current study are available from the Dr. Maurice BODA and can be requested via [email protected] Ethics Approval and Consent This study was authorized by the Cameroon National ethical committee under the authorization numbers (N°2016/01/696/CNERSH/SP and N o 2017/06/923/CE/CNERSH/SP) and research authorization were obtained from both the Littoral regional delegation and south West Regional delegation of Public Health under the number (N°: 1684/AR/MINSANTE/DRSPL/BCASS). A signed informed consent was obtained from the parent or the legal guardian of all the participant sampled. The study protocol conformed to the ethical guidelines of the 1975 declaration of Helsinki was approved by the National Ethics Committee and the Ministry of Public Health of Cameroon. Conflict of interest: The authors state that there is no conflict of interest. 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Global distribution of rotavirus serotypes/genotypes and its implication for the development and implementation of an effective rotavirus vaccine. Rev Med Virol. 2005;15(1):29–56. [PubMed: 15484186]. Martella V, Banyai K, Matthijnssens J, Buonavoglia C, Ciarlet M, Ciarlet J. Zoonotic aspects of rotaviruses. Vet Microbiol M. Matthijnssens J, Bilcke J, Ciarlet M, Martella V, Banyai K, Rhaman M, et al. Rotavirus disease and vaccination: impact on genotype diversity. Future Microbiol. 2009;4:1303–16. [PubMed: 19995190]. Gautam R, Mijatovic-Rustempasic S, Esona MD, Tam KI, Quaye O, Bowen MD. Onestep multiplex real-time RT-PCR assay for detecting and genotyping wild-type group A rotavirus strains and vaccine strains (Rotarix(R) and RotaTeq(R)) in stool samples. PeerJ. 2016;4(10):e1560. 10.7717/peerj.1560 . Mijatovic-Rustempasic S, Esona MD, Williams AL, Bowen MD. Sensitive and specific nested PCR assay for detection of rotavirus A in samples with a low viral load. J Virol Methods. 2016;236:41–6. 10.1016/j.jviromet.2016.07.007 . Bar-Zeev N, Kapanda L, Tate JE, Jere KC, Iturriza-Gomara M, Nakagomi O, et al. Effectiveness of a monovalent rotavirus vaccine in infants in Malawi after programmatic roll-out: an observational and case-control study. Lancet Infect Dis. 2015;15:422–8. Ndzé VN, Akum AE, Kamga GH, Enjema LE, Esona MD, Banyai K, et al. Epidemiology of rotavirus diarrhea in children under 5 years in Northern Cameroon. Pan Afr Med J. 2012;11(73). 10.11604/pamj.2012.11.73.1548 . Liu L, Johnson HL, Cousens S, Perin J, Scott S, Lawn JE, et al. Global, regional, and national causes of child mortality: an updated systematic analysis for 2010 with time trends since 2000. Lancet. 2012;379(9832):2151–61. Santos N, Hoshino Y. Global distribution of rotavirus serotypes/genotypes and its implication for the development and implementation of an effective rotavirus vaccine. Rev Med Virol. 2005;129–56. 10.1002/rmv.448 . Gasparinho C, Piedade J, Mirante MC, Mendes C, Mayer C, Nery SV, et al. Characterization of rotavirus infection in children with acute gastroenteritis in Bengo province, Northwestern Angola, prior to vaccine introduction. PLoS ONE. 2017;12(4). 10.1371/journal.pone.0176046 . e0176046. Luchs A, Timenetsky TSM. Group A rotavirus gastroenteritis: post-vaccine era, genotypes and zoonotic transmission. Einstein (Sao paulo). 2016;14(2):278–87. 10.1590/S1679-45082016RB3582 . Rakau K, Gededzha M, Peenze I, Seheri M. Rotavirus strains detected in Dr George Mukhari academic hospital and Oukasie primary healthcare, Pretoria from 2015–2016. In Proceedings of the 12th African Rotavirus Symposium, Johannesburg, South Africa, 30 July–1 August 201941. Gugu M, Nomcebo P, Sindisiwe D, Susan K, Gilbert M, Goitom W, Lonkululeko K, Xolsile D, Getahun T, Michael L et al. G3P[8] rotavirus strain causing diarrheal outbreak in the Kingdom of Eswatini, 2018. In Proceedings of the 12th African Rotavirus Symposium, Johannesburg, South Africa, 30 July–1 August 2019. Mhango C, Chinyama E, Mandolo J, Malamba C, Wachepa R, Kanjerwa O, Kamng’ona AW, Shawa IT, Jere KC. Changes in rotavirus strains circulating in Malawi before vaccine introduction and six years post vaccine era. In Proceedings of the 12th African Rotavirus Symposium, Johannesburg, South Africa, 30 July–1 August 2019. WHO-Botswana. Available online: https:// . (accessed on 29 May 2020). Carvalho-Costa FA, de Assis RMS, Fialho AM, Araujo IT, Silva MF, Gomez MM, Andrade JS, Rose TL, Fumian TM, Voloãto EM. The evolving epidemiology of rotavirus A infection in Brazil a decade after the introduction of universal vaccination with Rotarix(R). BMC Pediatr. 2019;19:42. [CrossRef]. Roczo-Farkas S, Kirkwood CD, Cowley D, Barnes GL, Bishop RF, Bogdanovic-Sakran N, Boniface K, Donato CM, Bines JE. The Impact of Rotavirus Vaccines on Genotype Diversity: A Comprehensive Analysis of 2 Decades of Australian Surveillance Data. J Infect Dis. 2018;218:546–54. [CrossRef]. Cowley D, Donato CM, Roczo-Farkas S, Kirkwood CD. Emergence of a novel equine-like G3P[8] inter-genogroup reassortant rotavirus strain associated with gastroenteritis in Australian children. J Gen Virol. 2015;97:403–10. [CrossRef]. Lorrot M, Vasseur M. Physiopathologie de la diarrhée à Rotavirus. Archives Pediatr. 2007;14(Supplement 3):145–S150. Mouré EAU, Aymard U, Banga-Mingo V, Gody CJ, Mwenda MM, Fandema J, et al. Emergence of G12 and G9 rotavirus genotypes in the Central African Republic, January 2014 to February 2016. BMC Res Notes. 2016;11:5. 10.1186/s13104-017-3122-7 . Da Silva Soares L, De Fatima Dos Santos GS, Socorro Lima D, Da Silva OA, De Fatima Costa DSF, Mascarenhas MEM, J. D., et al. Diversity of rotavirus strains circulating in Northern Brazil after introduction of a rotavirus vaccine: high prevalence of G3P[6] genotype. J Med Virol. 2014;86(6):1065–72. 10.10002/jmv.23797 . Page NA, Seheri LM, Groome MJ, Moyes J, Walaza S, Mphahlele J, Kahn K, Kapongo CN, Zar HJ, Tempia S, et al. Temporal association of rotavirus vaccination and genotype circulation in South Africa: Observations from 2002 to 2014. Vaccine. 2017;36:7231–7. [CrossRef]. Lartey BL, Damanka S, Dennis FE, Enweronu-Laryea CC, Addo-Yobo E, Ansong D, Kwarteng-Owusu S, Sagoe KW, Mwenda JM, Diamenu SK, et al. Rotavirus strain distribution in Ghana pre- and post- rotavirus vaccine introduction. Vaccine. 2018;36:7238–42. [CrossRef]. Hungerford D, Allen DJ, Nawaz S, Collins S, Ladhani S, Vivancos R, Iturriza-Gómara M. Impact of rotavirus vaccination on rotavirus genotype distribution and diversity in England, September 2006 to August 2016. Volume 24. Eurosurveillance; 2019. p. 1700774. Matthijnssens J, Zeller M, Heylen E, de Coster S, Vercauteren J, Braeckman T, van Herck K, Meyer N, Pircon J-Y, Soriano-Gabarro M, et al. Higher proportion of G2P[4] rotaviruses in vaccinated hospitalized cases compared with unvaccinated hospitalized cases, despite high vaccine effectiveness against heterotypic G2P[4] rotaviruses. Clin Microbiol Infect. 2014;20:O702–10. [CrossRef]. Luchs A, Cilli A, Morillo SG, de Cássia Compagnoli CR, Timenetsky MC. S.T. Rotavirus Genotypes Circulating in Brazil, 2007–2012: Implications for the Vaccine Program. Rev Inst Med Trop. 2015;57:305–13. [CrossRef] [PubMed]. Carvalho-Costa FA, Volotoa EM, De Assis RM, Fialho AM, De Andrade JS, Rocha LN, et al. Laboratory-based rotavirus surveillanve during the introduction of a vaccination program, Brasil, 2005–20009. Pediatr Infect Disease. 2011;30(1 Suppl):S35–41. Bar-Zeev N, Jere KC, Bennett A, Pollock L, Tate JE, Nakagomi O, Iturriza-Gomara M, Costello A, Mwansambo C, Parashar UD, et al. Population Impact and Effectiveness of Monovalent Rotavirus Vaccination in Urban Malawian Children 3 Years After Vaccine Introduction: Ecological and Case-Control Analyses. Clin Infect Dis. 2016;62:S213–9. [CrossRef]. Cunliffe NA, Witte D, Ngwira BM, Todd S, Bostock NJ, Turner AM, et al. Efficacy of human rotavirus vaccine against severe gastroenteritis in Malawian children in the first two years of life: a randomized, double-blind, placebo-controlled trial. Vaccine 30 Suppl. 2012;1 (01A36–43. 10.1016/j.vaccine.2011.09.120 . Additional Declarations No competing interests reported. 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Ghapoutsa","email":"","orcid":"","institution":"Department of Microbiology, Faculty of Science, The University of Yaoundé 1","correspondingAuthor":false,"prefix":"","firstName":"Rahinatou","middleName":"N.","lastName":"Ghapoutsa","suffix":""},{"id":590761740,"identity":"fe636495-df8c-4102-bea5-bc37cc34397c","order_by":2,"name":"Maurice Boda","email":"","orcid":"","institution":"Department of Microbiology, Faculty of Science, The University of Yaoundé 1","correspondingAuthor":false,"prefix":"","firstName":"Maurice","middleName":"","lastName":"Boda","suffix":""},{"id":590761741,"identity":"9f18fd87-5ac2-4d28-b678-f4e9752236a5","order_by":3,"name":"Mathew D. Esona","email":"","orcid":"","institution":"Diarrheal pathogens Research Unit, Department of Virology, Sefako Makgatho Health Sciences University, Medunsa 0204, Pretoria,","correspondingAuthor":false,"prefix":"","firstName":"Mathew","middleName":"D.","lastName":"Esona","suffix":""},{"id":590761742,"identity":"8a7fbf74-8792-4a0d-b638-60036ce06545","order_by":4,"name":"Julius M. Nwobegahay","email":"","orcid":"","institution":"Military Health Research Center (CRESAR)","correspondingAuthor":false,"prefix":"","firstName":"Julius","middleName":"M.","lastName":"Nwobegahay","suffix":""},{"id":590761743,"identity":"db400e0b-dd33-4481-b556-82aa15195f98","order_by":5,"name":"Valantine N. Ndze","email":"","orcid":"","institution":"University of Buea","correspondingAuthor":false,"prefix":"","firstName":"Valantine","middleName":"N.","lastName":"Ndze","suffix":""},{"id":590761744,"identity":"81a79368-d9da-4de5-bf6d-d89269aa80e1","order_by":6,"name":"Lesley N. Ngum","email":"","orcid":"","institution":"Institute for Medical Research and Medicinal Plant Studies (IMPM), Cameroon","correspondingAuthor":false,"prefix":"","firstName":"Lesley","middleName":"N.","lastName":"Ngum","suffix":""},{"id":590761745,"identity":"eea6c218-0680-4c46-94af-3c35164ce8a5","order_by":7,"name":"Palmer Masumbe Netongo","email":"data:image/png;base64,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","orcid":"","institution":"University of Yaoundé I (MDRG-BTC- UYI)","correspondingAuthor":true,"prefix":"","firstName":"Palmer","middleName":"Masumbe","lastName":"Netongo","suffix":""},{"id":590761746,"identity":"6f6b04bc-6322-47af-a904-44a01d16ece6","order_by":8,"name":"Maximilienne Ascension Nyegue","email":"","orcid":"","institution":"Department of Microbiology, Faculty of Science, The University of Yaoundé 1","correspondingAuthor":false,"prefix":"","firstName":"Maximilienne","middleName":"Ascension","lastName":"Nyegue","suffix":""}],"badges":[],"createdAt":"2025-11-25 04:53:22","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8198863/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8198863/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":102762271,"identity":"7a774f70-bdb8-4477-b0d9-0146dc1c9f9b","added_by":"auto","created_at":"2026-02-16 10:48:45","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":119499,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003ePost-vaccinal distribution of RVA Genotypes in Littoral and Kumba, South West Regions of Cameroon.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8198863/v1/cb56d406ca070acccbc9719f.png"},{"id":103049238,"identity":"a265785d-abe3-46a2-9afa-e0d935e8d580","added_by":"auto","created_at":"2026-02-20 07:38:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1099774,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8198863/v1/c1d4b06e-7962-4cda-a737-b77df2cca766.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Post-vaccine surveillance of Group A Rotavirus Strains circulating in the Littoral and South West Regions of Cameroon","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eRotavirus group A (RVA) is a leading etiological agent of severe diarrhea in infants and young children under five years of age, accounting for an estimated 128,500 deaths annually worldwide [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. The disease burden is disproportionately high in sub-Saharan Africa, where RVA remains one of a major cause of hospitalizations for acute gastroenteritis in children, resulting in substantial medical and socioeconomic impacts [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. In Cameroon, RV accounts for more than 5800 deaths yearly among children under 5 years of age in Cameroon and accounted for 33 to 38.1% of diarrhea-related hospitalizations in this age group [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTo reduce the global disease burden, four oral vaccines, RotaTeq, Rotarix\u0026reg;, ROTAVAC, and Rotasiil, have been approved and recommended by World Health Organization (WHO). These vaccines have been incorporated into routine immunization programs in over one hundred (100) countries. Post vaccine surveillance in some of these countries have revealed a significant reduction in RVA-associated morbidity and mortality globally [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePrior to the introduction of rotavirus vaccine Douala, Edea, Nkongsamba (littoral) and Kumba (Southwest) in Cameroon, RVA surveillance was primarily driven by independent research initiatives. In 2007, a collaborative effort between the U.S (Centers for Disease Control and Prevention, CDC-Atlanta) and the Cameroon Ministry of Health, under the Surveillance Strengthening Project in Central Africa (SURVAC), established a national framework for RVA surveillance. Data collected during the pre-vaccine era revealed considerable genotype diversity and temporal variation across regions. For instance, Esona et al. (2010) identified G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] as the predominant strain in Western Cameroon during the 1999\u0026ndash;2000 rotavirus season [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], while G9P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] predominated in Yaound\u0026eacute; (the Central region of Cameroon) during 2008\u0026ndash;2010 [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Ndze et al. (2011) later reported the emergence of G12 as the most prevalent genotype in the Far North and Northwest regions during 2010\u0026ndash;2011 [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. This epidemiological background informed the adoption of Rotarix\u0026reg; into Cameroon\u0026rsquo;s Expanded Vaccination Program (EPI) on March 28, 2014 [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Despite, WHO recommended surveillance programmes at sentinel sites across Africa to monitor the burden of rotavirus disease and circulating strains before and after vaccine introduction as one of the crucial tools in measuring the impact of rotavirus vaccines [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], Cameroon unlike some African countries has paucity in post-vaccine circulating RV strains. This study therefore aims to characterize the genotypic diversity of RVA strains circulating in the Littoral and Southwest regions of Cameroon during the post-vaccine introduction period.\u003c/p\u003e \u003cp\u003eRotavirus gastroenteritis in humans is associated with mainly six genotype combinations ; G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], G4P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], G9P [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and G12P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], causing majority of infections [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Although the distribution of these six globally important rotavirus genotypes can change dramatically in regions from year to year, the G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] rotavirus strain has remained the most prevalent strain worldwide [\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. However, significant diversity of rotavirus genotypes continues to be observed worldwide with several novel combinations due to accumulation of point mutations, genome re-assortments, and/or zoonotic transmission to human host resulting in the introduction of new antigenic variants across regions [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Confronted with the genetic diversity of RVA and the potential for regional genotype shifts, continuous molecular surveillance is critical to monitor the circulating post-vaccine strain. Such data are essential for evaluating vaccine effectiveness, guiding public health policy, and informing future vaccine development.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eEthical and administrative considerations\u003c/h2\u003e \u003cp\u003e Prior to initiating this study, ethical approval was obtained from the Cameroon National Ethics Committee (Approval Nos. 2016/01/696/CNERSH/SP and 2017/06/923/CE/CNERSH/SP). Research authorization was also granted by the Littoral and Southwest Regional Delegations of Public Health (Authorization No. 1684/AR/MINSANTE/DRSPL/BCASS). Written informed consent was obtained from a parent or legal guardian of each participating child. The study protocol adhered to the principles outlined in the Declaration of Helsinki (1975) and was endorsed by the Ministry of Public Health of Cameroon.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eStudy population, period and sample collection\u003c/h3\u003e\n\u003cp\u003eThis cross-sectional study was conducted in two phases: from May 2015 to April 2016 in the Littoral region, and from July 2017 to June 2018 in Kumba, Southwest region of Cameroon. Diarrheal stool samples were collected from children under five years of age presenting at the pediatric departments of the following health facilities:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eLittoral Region: Laquintinie Hospital, Bonassama District Hospital, Deido District Hospital, Ed\u0026eacute;a Regional Hospital, and Nkongsamba Regional Hospital.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eSouth-west Region: Kumba District Hospital, Baptist Health Centre, Ekona District Hospital, and Bambini Pediatric Foundation.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eChildren with bloody diarrhea or aged over five years were excluded. For each enrolled child, demographic and clinical data - including vaccination status and breastfeeding history - were obtained from medical records and/or guardians. All stool samples were transported in cool boxes (maintained at 4\u0026ndash;8\u0026deg;C) to the Virology Laboratory of the Mother and Child Center of the Chantal Biya Foundation and the Military Health Research Center (CRESAR), Yaound\u0026eacute;, following standard biosafety protocols.\u003c/p\u003e\n\u003ch3\u003eStool processing and nucleic acid extraction\u003c/h3\u003e\n\u003cp\u003eA 10% (v/v) stool suspension was prepared in nuclease-free distilled water (Invitrogen\u0026trade;) for RNA extraction. Samples were stored at \u0026minus;\u0026thinsp;20\u0026deg;C until processing. Total RNA was extracted manually using the QIAamp\u0026reg; Viral RNA Mini Kit (Qiagen, Hilden, Germany) according to the manufacturer\u0026rsquo;s protocol. The RNA extracts were subsequently stored at \u0026minus;\u0026thinsp;80\u0026deg;C until use.\u003c/p\u003e \u003cp\u003eAs an internal process control, 2 \u0026micro;L of MS2 bacteriophage RNA (10⁹ units/\u0026micro;L; ZeptoMetrix, Buffalo, NY, USA) was spiked into 48 \u0026micro;L or 98 \u0026micro;L of each stool suspension prior to extraction. All samples and reagents were equilibrated to room temperature before use.\u003c/p\u003e\n\u003ch3\u003eRVA NSP3 gene detection by qRT-PCR\u003c/h3\u003e\n\u003cp\u003eDetection of the RVA NSP3 gene was performed by qRT-PCR (Qiagen, Inc. Valencia, CA) following the manufacturer's instructions.\u003c/p\u003e\n\u003ch3\u003eGenetic Typing of RVA\u003c/h3\u003e\n\u003cp\u003eSamples positive for the rotavirus NSP3 gene underwent further genotyping using both multiplex real-time RT-PCR and nested RT-PCR approaches.\u003c/p\u003e \u003cp\u003eThe multiplex real-time RT-PCR assay targeted specific markers in the VP7 and VP4 genes to simultaneously detect wild-type and vaccine strains (Rotarix\u0026reg; and RotaTeq\u0026reg;), while including MS2 RNA as an internal control [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The assay covered the following genotypes: G1, G2, G3, G4, G9, G12, P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], as well as vaccine strains.\u003c/p\u003e \u003cp\u003eNested RT-PCR was also performed for VP7 and VP4 genotyping. This involved two rounds of conventional RT-PCR using genotype-specific primer sets, with the second round using the amplicon from the first reaction as the template. Amplicons were analyzed by agarose gel electrophoresis to determine the genotype [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e- Demographic characteristics\u003c/h2\u003e \u003cp\u003eDiarrheic stool samples were collected from 197 children of both gender with age ranging from 0\u0026ndash;59 months, consulting or hospitalized for severe diarrhea in the Littoral region and South west region (Kumba) of Cameroon.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003e- Vaccination status\u003c/h3\u003e\n\u003cp\u003eOut of the total sample collected, 63% (124/197) of these children had received both doses of Rotarix vaccine, while only 22% (43/197) were unvaccinated and 15% (30/197) had unknown vaccination status.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e- Regional distribution of Genotypes\u003c/h2\u003e \u003cp\u003eOut of the 197 samples collected, 87 were genotyped with 28 from the Littoral region and 59 from Kumba South West Region of Cameroon. The individual P and G genotypes per area of study is represented on Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e below;\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cem\u003eCirculating P and G genotypes in Littoral region and Kumba, South West region of Cameroon\u003c/em\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGenotypes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLittoral Region\u003c/p\u003e \u003cp\u003eNumber and (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eKumba SWR\u003c/p\u003e \u003cp\u003eNumber and (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e \u003cp\u003e\u003cspan type=\"BoldUnderline\" class=\"BoldUnderline\" name=\"Emphasis\"\u003eG genotypes\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (14.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e36 (61%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 (46.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (35.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22 (37.3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGNT\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (1.7%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e \u003cp\u003e\u003cspan type=\"BoldUnderline\" class=\"BoldUnderline\" name=\"Emphasis\"\u003eP genotypes\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (17.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (21.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22 (37.3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (50.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e37 (62.7%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP[NT]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (7.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003eWhere NT\u0026thinsp;=\u0026thinsp;non-typed\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eCirculating VP7 genotypes\u003c/h2\u003e \u003cp\u003eThe 87 samples characterized for G-specificity reveals 5 different RV VP7 genotypes including G1, G2, G3, G9, G12. G1 was characterized in both study area and most predominant in Kumba (61%) and third predominant (14.3%) in the Littoral region of Cameroon. G2 was the most predominant VP7 genotypes in the Littoral region (46.4%) although not fouind circulating in Kumba. The second predominant G-genotype in the Littoral region was G3 (35.7%) followed by G9 (3.6%) although both G3 and G9 were not found circulating in Kumba. The G12 (37.3%) genotype was second predominant in kumba. 1% of the G-type was not typeable.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eCirculating VP4 genotypes\u003c/h2\u003e \u003cp\u003eA total of 87 samples were characterized for P specificity from both area of study. 3 different VP4 genotypes were characterized including P [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], P [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] and P [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. P [[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] was the most predominant in Kumba and Littoral regions with respective percentages of 62.7% and 50% respectively. P [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] was the second predominant in both regions with percentages of 37.3% in Kumba and 21.4% in the Littoral region. P [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] was found circulating only in the Littoral region at 17.9% Mixed infections were observed at 3.6%, whereas 7.1% of the strains were non-typeable as seen on Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e above.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eGenotype distribution in Littoral region and Kumba\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDistribution of Genotypes in Littoral and Kumba\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGenotype Combinations\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLittoral Region\u003c/p\u003e \u003cp\u003eFrequency/ Percentages\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eKumba (SWR)\u003c/p\u003e \u003cp\u003eFrequency/ Percentages\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG1P [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (14.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e34 (57.6%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG1P [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (3.4%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG2P [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (17.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG2P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (7.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG2P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (10.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG2P[NT]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (7.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG3P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (14.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (21.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG9P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG12P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (32.8%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG12P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (5.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGNTP[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (1.7%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTOTAL\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e28\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e59\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003e\u003cb\u003eWhere nt\u0026thinsp;=\u0026thinsp;non-typed\u003c/b\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eDistribution of genotypes in Littoral region\u003c/h2\u003e \u003cp\u003eFrom the 130 samples collected in the Littoral region, 28 were successfully genotyped as seen on Table \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e above. G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] were the most predominant (with respective percentages of 21.4% and 17.9%), followed by G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (14.3%), G3P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] (14.3%), G2P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (10.7%), G2P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] (7.1%) and G9P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (3.6%). The presence of a rare combination, G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (3.6%) as well as partially determined genotypic combinations G2P[nt] (7.1%) were identified.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eDistribution of genotypes in Kumba, South West Region\u003c/h2\u003e \u003cp\u003eOf the 59/67 genotyped samples from this region, the most common genotype combination was G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (57.6%), followed by G12[P6] (32.8%). While the least common genotype combinations were G12P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (5.1%) and G1P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] (3.4%). A partially determined genotypic combinations GntP[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] (1.7%) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cb\u003ePost-vaccinal distribution of RVA Genotypes in Littoral Region and in Kumba, South West Regions of Cameroon (2015\u0026ndash;2018).\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/p\u003e \u003cp\u003eA total of 87 samples were genotyped in both area of study revealing the most common genotype combination to be G1P [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (44%), followed by G12 P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] (22%). The least common genotype combinations were G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (7%), G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] (6%), G3P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] (5%), G2P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (4%), G12P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (3%), G1P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] (2%), G2P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] (2%) and 1% of G9P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], with the presence of a rare combination, G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (1%)as well as partially determined genotypic combinations G2P[NT] (2%) and GNT P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] (Fig.\u0026nbsp;1).\u003c/p\u003e \u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eAlthough Cameroon has actively participated in the WHO surveillance programme and introduced the monovalent Rotavirus vaccine (Rotarix, GSK) in March 2014 into the EPI program of Cameroon, there is no available molecular data and information on circulating strains of RVA in the country. This present study aims at characterizing circulating post vaccinal RVA genotypes in Littoral and South West Region (Kumba) of Cameroon.\u003c/p\u003e \u003cp\u003eThis post vaccinal study reveals strains carrying G1 (61%) and G12 (37.3%) genotypes as the most common VP7 genotpes in Kumba usually found in combinations of P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] VP6 genotypes. Most of the common genotypes identified in the Littoral region were (G2, G3, G1) usually found in combinations with P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] and P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] VP4 genotypes (Tables\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eIn contrast to the G1 genotype which remained the most predominant in the pre and post vaccinal era in Kumba, the G2 strain although not found circulating in Kumba was the most predominant VP7 genotype isolated in the littoral region. The predominance of the G2 genotype was also noted after the introduction of the vaccine in Malawi [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The presence of G1 genotype in Kumba was observed at a lower prevalence compared to pre-vaccinal era. This lower prevalence might be due to the emergence of other genotypes such as G12 identified as the second predominant in this post vaccinal era in Kumba accounting for 37.3% circulating G genotypes in Kumba. Although the G12 was not found circulating in the pre-vaccinal era in Kumba, it has been long time found circulating in the pre-vaccinal era in Northern Cameroon [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe P [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] genotype was the most predominant in both area of study in the pre and post vaccinal era in Cameroon followed by P [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] genotype in the pre-vaccinal era, remained the most predominant even after the introduction of Rotarix in Littoral and Kumba with respective percentages of 50% and 62.7%. The P [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] genotype being the second predominant is thought to infect animal species [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] and accounts for one third of P genotypes reported in other studies in Africa [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. After the introduction of RVA vaccines in African countries, P [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] is increasingly detected across the continent [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], a fact that our results appear to support. The high prevalence of genotypes with high zoonotic potential, G3 and P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], may be linked to the domestic breeding of cattle, dogs and pigs in Africa [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eGlobally, the predominant genotypic combinations are G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], G4P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and G9P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. This study reveals G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], G3P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] and G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] genotypes to be the majority in the Littoral region representing 67.9% of RVA infections. However, G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (21.4%) was the most isolated genotypic combination in the littoral region unlike globally and other studies carried out in Cameroon before the introduction of the vaccine. Several countries reported G3 in combination with P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] during the 12th African Rotavirus Symposium 2019 [\u003cspan additionalcitationids=\"CR26\" citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]: Botswana reported an outbreak of G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] in 2018 [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e], Malawi (introduced vaccine in 2012, reported G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] in 2018), Kingdom of Eswatini (introduced vaccine in 2015, reported G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] in 2018). Around the world, the emergence of genotype G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and equine-like G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] in 2013 in Australia and re-emergence of G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] were observed in Brazil in the post-vaccine introduction [\u003cspan additionalcitationids=\"CR30\" citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. This could be linked to its antigenic composition different from that of the vaccine which would allow it to escape immune pressure in particular from vaccines since this strain was taken into account in the design and testing of the Rotarix vaccine [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. The G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] genotype combination was the most predominant in Kumba during this study period, accounting for 57.6% RVA infection in this region. The predominant and sustained circulation of G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] strains was observed several years in a row, before the introduction of the vaccine, particularly in the studies of Esona and collaborators, where 37.1% of G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] strains was recorded; then in the study by Boula and his team where 44% of G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] was noted. This strain is also predominant in the Central African Republic where 37% of G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] strains have been reported [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. Although the G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] strain showed its predominance in Kumba after vaccine introduction, it had a low appearance rate (14.3%) in the Littoral region.\u003c/p\u003e \u003cp\u003eThis study also confirms the emergence of the G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] (17.9%) and G3P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] (14.3%) strains in the littoral region and G12 P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] (32.8%) and G12 P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (5.1%) in Kumba which have become globally important. The prevalence of G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] obtained in this study was higher than any observed in Cameroon in the past [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. A similar result was registered in Belgium and Brazil after the exclusive use of the monovalent Rotarix vaccine which led to an increase in G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] strain [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. The sudden appearance of G12P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] rotavirus strains soon after the introduction of rotavirus vaccines in Kumba is quite interesting. During the pre-vaccinal study in Cameroon, the G12P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] strain was mainly isolated in Bamenda and Maroua [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] and WHO African Rotavirus surveillance programme showed the emergence of G12 strains as the dominant strain in Nigeria and Senegal, countries that had not yet introduced rotavirus vaccines in their immunization programme. Therefore, the observed emergence of G12 strains post-vaccine introduction may not be associated with vaccine introduction and may represent natural secular variation in rotavirus strains.\u003c/p\u003e \u003cp\u003eThe identification of the mixed genotype P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] in the Littoral region highlights reassortment events originating from co-circulating local strains. Complete genome sequencing of the strains would be necessary for in-depth characterization and determination of the degree of natural reassortment. The presence of indeterminate P (P[nt]) and G (Gnt) genotype in Littoral and Kumba respectively, is not a common issue but has been often observed in low-income countries [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Thus, Esona and his team in 2010 demonstrated that the majority of non-typable tensions encountered in Africa can be genotyped, with the use of specific primers or improve genotyping techniques [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. In this study, it is possible that some of the rare RVA genotypes were present among the non-typeable strains. To confirm this, further research needs to be done using more specific primers that will allow genotype of rare strains or new strains.\u003c/p\u003e \u003cp\u003eThe presence of the G1 or P [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] strains among vaccinated children who have received both doses of the Rotarix vaccine in this study reveals vaccination status does not prevent the occurrence of RVA infection in vaccinated or unvaccinated children. The G1 P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] strain was seen at its peak in kumba although with lower appearance rate (14.3%) in the littoral region but with a rise in other genotype combinations (G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], G3P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], G2P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], G2P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]). Countries that introduced the monovalent Rotarix\u0026reg; vaccine similar to Cameroon, reported similar results with a decline of the genotype combination G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] with a concurrent rise in other combinations in the post-vaccine period. For example, South Africa reported an increase in non-G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] strains [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e], in contrast to Malawi where the reduction of G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] was not significant [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. In Ghana, G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] returned as one of the dominant strains in the fourth year post-vaccine introduction [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Other studies reported from England, Brazil, Belgium, Scotland, a decline in the proportion of G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] with a rise in the proportion of heterotypic strains, such as G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], was observed [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe presence of the G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], G3P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], G2P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] and G12 P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] strains isolated from children who received a full dose of Rotarix in both area of study reports lower vaccine effectiveness against strains that do not share any G and/or P specific genotype with Rotarix voltages (G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]). This hypothesis is in agreement with studies that were carried out during mass vaccination with the Rotarix vaccine, notably in Latin America, Australia and Europe where G2P [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] dominated other strains over several RVA seasons [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Additionally, Belgium reported a slightly lower vaccine effectiveness against G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], and in Malawi, a lower vaccine effectiveness against G2 strains than G1 strains was reported [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHowever, experts believe that the possibility of high reappearance of G2P [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] in the Littoral region could be the result of the natural variation of Rotavirus strains [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. In other words, these children who had received a full dose of Rotarix were instead protected against strains having a combination with one of the genotypes found in the vaccine but might be vulnerable to other genotypes, although recent theories suggest that vaccine failure cannot be a direct consequence of the circulation of rare strains of RVA in African countries [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]. This could be explained by the fact that these strains share sequences different from those of the vaccine strain.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConclusion\u003c/strong\u003e \u003cp\u003eThis is the first Rotavirus post-vaccinal report describing the circulation of Rotavirus genotypes in two study areas in Cameroon. The results obtained highlights the predominance of G1P [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and showed a shift in circulating genotypes following vaccine introduction. In addition, the emergence of unusual strains, such as G2P [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], G3P [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] and G12P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] not under the vaccine coverage was also observed, which underscore the need for continued country-wide surveillance to monitor changes, due to possible vaccine pressure, and consequently, the effect on vaccine effectiveness.\u003c/p\u003e \u003c/p\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eThe limitations of this study are due to the fact that the period of sample collection from the area of study was different. In the Littoral region, the samples were collected from May 2015 - April 2016 and in Kumba, sample collection was from July 2017-June 2018.\u003c/p\u003e \u003cp\u003e \u003cb\u003eAbreviations\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eCDC\u003c/b\u003e: Center for Diseases control and prevention;\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eELISA\u003c/b\u003e: Enzyme linked immunosorbent assay;\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eEPI\u003c/b\u003e: Expanded program on immunization;\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eNSP\u003c/b\u003e: Non-structural protein;\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eqRT-PCR\u003c/b\u003e: Quantitative reverse transcription-polymerase chain reaction;\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eRNA\u003c/b\u003e: Ribonucleic acid;\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eRT-PCR\u003c/b\u003e: Reverse transcriptase-polymerase chain reaction;\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eRVA\u003c/b\u003e: Group a rotavirus;\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eSURVAC\u003c/b\u003e: Surveillance Strengthening Project in Central Africa\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eVP\u003c/b\u003e: Viral protein;\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eWHO\u003c/b\u003e: World Health Organization\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Abbreviations","content":"\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eCDC\u003c/strong\u003e: Center for Diseases control and prevention;\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eELISA\u003c/strong\u003e: Enzyme linked immunosorbent assay;\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eEPI\u003c/strong\u003e: Expanded program on immunization;\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eNSP:\u003c/strong\u003e Non-structural protein;\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eqRT-PCR\u003c/strong\u003e: Quantitative reverse transcription-polymerase chain reaction;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eRNA\u003c/strong\u003e: Ribonucleic acid;\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eRT-PCR\u003c/strong\u003e: Reverse transcriptase-polymerase chain reaction;\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eRVA\u003c/strong\u003e: Group a rotavirus;\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eSURVAC\u003c/strong\u003e: Surveillance Strengthening Project in Central Africa\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eVP:\u003c/strong\u003e Viral protein;\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eWHO\u003c/strong\u003e: World Health Organization\u0026nbsp;\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe express our gratitude to Dr. Mathew Dr. ESONAof the Department of Virology (Sefako Makgatho Health Sciences University Pretoria, South Africa) and Dr. BODA Maurice for ensuring the supplies of all what was needed to ensure the success of this research. The Chief of Centre and Staff of the Military Health Research Centre (CRESAR), Yaound\u0026eacute; for supervision and technical support, the children and their parents who participated in this study and the pediatric services of the Laquintinie hospital, the district hospitals of Bonassama and Deido, the regional hospitals of Ed\u0026eacute;a and Nkongsamba all of the littoral region and the pediatric services of Kumba District Hospital, the Baptist Health Centre, the Ekona District Hospital and Bambini Pediatric Foundation of the South West Region.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBench and data analysis: CNE, RNG, MB, MDE . Reagents/materials and analysis tools: MDE, JMN, MB. Manuscript preparation: CNE, RNG, PMN, MB, MDE. Study designed: MB, MDE, PMN, MAN, JMN. Field work activities: CNE, RNG, MB, PMN, LNN. Laboratory work: CNE, RNG, MB, MDE, JMN, VNN. Supervision: MAN, MB, PMN, JMN, MDE, MDB. All the authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was supported by the personal funds of the authors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe datasets used and analyzed during the current study are available from the Dr. Maurice BODA and can be requested via [email protected]\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval and Consent\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was authorized by the Cameroon National ethical committee under the authorization numbers (N\u0026deg;2016/01/696/CNERSH/SP and N\u003csup\u003eo\u003c/sup\u003e 2017/06/923/CE/CNERSH/SP) and research authorization were obtained from both the Littoral regional delegation and south West Regional delegation of Public Health under the number (N\u0026deg;: 1684/AR/MINSANTE/DRSPL/BCASS). A signed informed consent was obtained from the parent or the legal guardian of all the participant sampled. The study protocol conformed to the ethical guidelines of the 1975 declaration of Helsinki was approved by the National Ethics Committee and the Ministry of Public Health of Cameroon.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest:\u0026nbsp;\u003c/strong\u003eThe authors state that there is no conflict of interest.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication:\u0026nbsp;\u003c/strong\u003eNot applicable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u0026nbsp;\u003c/strong\u003eNo competing interests.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eTroeger C, Ibrahim AK, Puja CR, Shujin C, Blacker BF, Tahmeed A, et al. Rotavirus Vaccination and the Global Burden of Rotavirus Diarrhea Among Children Younger Than 5 Years. 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BMC Res Notes. 2016;11:5. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s13104-017-3122-7\u003c/span\u003e\u003cspan address=\"10.1186/s13104-017-3122-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDa Silva Soares L, De Fatima Dos Santos GS, Socorro Lima D, Da Silva OA, De Fatima Costa DSF, Mascarenhas MEM, J. D., et al. Diversity of rotavirus strains circulating in Northern Brazil after introduction of a rotavirus vaccine: high prevalence of G3P[6] genotype. J Med Virol. 2014;86(6):1065\u0026ndash;72. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.10002/jmv.23797\u003c/span\u003e\u003cspan address=\"10.10002/jmv.23797\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePage NA, Seheri LM, Groome MJ, Moyes J, Walaza S, Mphahlele J, Kahn K, Kapongo CN, Zar HJ, Tempia S, et al. Temporal association of rotavirus vaccination and genotype circulation in South Africa: Observations from 2002 to 2014. Vaccine. 2017;36:7231\u0026ndash;7. [CrossRef].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLartey BL, Damanka S, Dennis FE, Enweronu-Laryea CC, Addo-Yobo E, Ansong D, Kwarteng-Owusu S, Sagoe KW, Mwenda JM, Diamenu SK, et al. Rotavirus strain distribution in Ghana pre- and post- rotavirus vaccine introduction. Vaccine. 2018;36:7238\u0026ndash;42. [CrossRef].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHungerford D, Allen DJ, Nawaz S, Collins S, Ladhani S, Vivancos R, Iturriza-G\u0026oacute;mara M. Impact of rotavirus vaccination on rotavirus genotype distribution and diversity in England, September 2006 to August 2016. Volume 24. Eurosurveillance; 2019. p. 1700774.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMatthijnssens J, Zeller M, Heylen E, de Coster S, Vercauteren J, Braeckman T, van Herck K, Meyer N, Pircon J-Y, Soriano-Gabarro M, et al. Higher proportion of G2P[4] rotaviruses in vaccinated hospitalized cases compared with unvaccinated hospitalized cases, despite high vaccine effectiveness against heterotypic G2P[4] rotaviruses. Clin Microbiol Infect. 2014;20:O702\u0026ndash;10. [CrossRef].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLuchs A, Cilli A, Morillo SG, de C\u0026aacute;ssia Compagnoli CR, Timenetsky MC. S.T. Rotavirus Genotypes Circulating in Brazil, 2007\u0026ndash;2012: Implications for the Vaccine Program. Rev Inst Med Trop. 2015;57:305\u0026ndash;13. [CrossRef] [PubMed].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCarvalho-Costa FA, Volotoa EM, De Assis RM, Fialho AM, De Andrade JS, Rocha LN, et al. Laboratory-based rotavirus surveillanve during the introduction of a vaccination program, Brasil, 2005\u0026ndash;20009. Pediatr Infect Disease. 2011;30(1 Suppl):S35\u0026ndash;41.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBar-Zeev N, Jere KC, Bennett A, Pollock L, Tate JE, Nakagomi O, Iturriza-Gomara M, Costello A, Mwansambo C, Parashar UD, et al. Population Impact and Effectiveness of Monovalent Rotavirus Vaccination in Urban Malawian Children 3 Years After Vaccine Introduction: Ecological and Case-Control Analyses. Clin Infect Dis. 2016;62:S213\u0026ndash;9. [CrossRef].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCunliffe NA, Witte D, Ngwira BM, Todd S, Bostock NJ, Turner AM, et al. Efficacy of human rotavirus vaccine against severe gastroenteritis in Malawian children in the first two years of life: a randomized, double-blind, placebo-controlled trial. Vaccine 30 Suppl. 2012;1 (01A36\u0026ndash;43. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.vaccine.2011.09.120\u003c/span\u003e\u003cspan address=\"10.1016/j.vaccine.2011.09.120\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-infectious-diseases","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"infd","sideBox":"Learn more about [BMC Infectious Diseases](http://bmcinfectdis.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/infd","title":"BMC Infectious Diseases","twitterHandle":"#bmcinfectdis","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"/Concepts: Rotavirus, RT-PCR, Genotype, Circulating Strains, Rotarix, Littoral, Kumba, Cameroon","lastPublishedDoi":"10.21203/rs.3.rs-8198863/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8198863/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground:\u003c/h2\u003e \u003cp\u003eThe effectiveness of Group A Rotavirus (RVA) vaccine in low-income countries has been limited, partly due to the circulation of strains not covered by existing vaccines. Despite the introduction of Rotarix (2014) in Cameroon, no nationwide studies have characterized circulating RVA strains. This study provides post-vaccination of RVA genotyping data from the Douala, Edea, Nkongsamba (Littoral) and Kumba (Southwest) regions of Cameroon.\u003c/p\u003e\u003ch2\u003eMethods:\u003c/h2\u003e \u003cp\u003eA cross-sectional study was carried out on 197 diarrheal samples and vaccination data collected from children under five from the Littoral region (n\u0026thinsp;=\u0026thinsp;130; May 2015 - April 2016) and Kumba Southwest (n\u0026thinsp;=\u0026thinsp;67; July 2017 - June 2018). RVA NSP3 gene was detected using qRT-PCR and the NSP3-positive samples underwent one-step multiplex RT-PCR for genotyping wild-type and vaccine strains, with VP4 and VP7 typing performed via nested PCR.\u003c/p\u003e\u003ch2\u003eResults:\u003c/h2\u003e \u003cp\u003eOf the 197 children, 63% were fully vaccinated with Rotarix, 22% were unvaccinated, and 15% had unknown status. A total of 87 samples were successfully genotyped (28 from Littoral, 59 from Kumba). Five VP7 (G) genotypes were identified: G1, G2, G3, G9, and G12. In Littoral, G2 (46.4%) and G3 (35.7%) predominated, while G1 (61%) and G12 (37.3%) were most common in Kumba. VP4 (P) genotypes included P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], and P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], with P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] being most frequent in both regions. Mixed infections (3.6%) and non-typeable strains (7.1%) were also observed. Dominant G-P combinations included G3P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and G2P[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] in Littoral, and G1P[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and G12P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] in Kumba. Rare and partially typed strains were also detected.\u003c/p\u003e\u003ch2\u003eConclusion:\u003c/h2\u003e \u003cp\u003eThis study highlights the predominance of G1P [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] in vaccinated children and the emergence of non-vaccine-covered strains such as G2P [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], G3P [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], and G12P[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. These findings underscore the need for ongoing surveillance and potential vaccine adjustments.\u003c/p\u003e","manuscriptTitle":"Post-vaccine surveillance of Group A Rotavirus Strains circulating in the Littoral and South West Regions of Cameroon","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-16 10:48:41","doi":"10.21203/rs.3.rs-8198863/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-03-13T06:35:05+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-11T14:00:29+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-05T13:07:18+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-05T12:46:22+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"259445107491097781213268654548487910003","date":"2026-02-18T18:59:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"76556796352986866670446911711577154586","date":"2026-02-13T09:06:32+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"329554864905535136194917242072337997661","date":"2026-02-11T06:36:11+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-11T06:29:07+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-01-01T06:24:22+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-12-05T05:42:17+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-12-05T05:40:51+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Infectious Diseases","date":"2025-11-25T04:50:19+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-infectious-diseases","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"infd","sideBox":"Learn more about [BMC Infectious Diseases](http://bmcinfectdis.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/infd","title":"BMC Infectious Diseases","twitterHandle":"#bmcinfectdis","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b0f47e48-7a63-48e1-9063-153e0d824734","owner":[],"postedDate":"February 16th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-05-15T05:25:06+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-16 10:48:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8198863","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8198863","identity":"rs-8198863","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}