Assessment of Longevity of COVID-19 Vaccination Among Hematology Healthcare Workers

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Khoshnaw, Karzan R. Sdiq, Dlzar D. Ghafoor, Rafal M. Kamil, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3834361/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background The SARS-CoV-2 outbreak caused pneumonia and respiratory distress worldwide in December 2019. It was later recognized as the COVID-19 pandemic, so COVID-19 specific vaccines were soon developed and used for immunization of global communities. The primary objective of this study is to measure the concentration and persistence of IgG antibodies against SARS-CoV-2in healthcare employees of Hiwa Hospital for Cancer in Sulaimani City, Iraq. Patients and Methods : Blood samples were collected from 49 healthcare employees in Hiwa Hospital who received the Pfizer-BioNTech COVID-19 vaccine. The participants were recruited through a questionnaire containing information about age, gender, number of vaccination doses, and frequency of previous COVID-19 infections. The anti- COVID-19 antibodies in the blood samples were analyzed using the ELISA technique. Results The age of the participants ranged from 30 to 39 years old (mean 38.9 ± 10.29), with 31 (63.5%) being males and 18 (36.7%) being females. The anti COVID-19 specific IgG titers were 12.5, 13.45, and 13.8 mg/dL after 6, 12 and 18 months of vaccination, respectively. Besides, 10.2% of the participants have received three doses of the vaccines, 85.7% have received two doses, and only (4.1%) received a single dose. Moreover, a faction (22.4%) of the participants had a very low positive titer of anti COVID-19 specific IgM without obvious signs and symptoms of the disease. Conclusion The Immunoglobulin G antibody titer against COVID-19 remains at a protective level for at least eighteen months. SARS-CoV-2 COVID-19 Vaccination Pfizer Figures Figure 1 Introduction The COVID-19 pandemic, which caused over 200 million cases and 4 million fatalities globally, has had a significant impact on health and the global economy ( 1 ). SARS-COV-2 is a member of the Coronaviridae family with a genetic material of RNA (+ ssRNA). The 3'-end of the viral genome encodes four structural proteins: spike (S), nucleocapsid (N), envelope (E), and membrane (M). The spike proteins are immunogenic and enhance the pathogenic effects of the virus ( 2 ). The virus enters pneumocytes through angiotensin-converting enzyme receptor 2 (ACE-2), causing acute respiratory syndrome (viral pneumonia). The virus uses spikes to connect to respiratory cells, binding to ACE-2 in kidneys, lungs, endothelial cells, liver, and blood vessels ( 3 , 4 ). ACE-2 facilitates protein cleavage, causing the virus to reproduce and burst cells, causing symptoms like sore throat, fever, and muscle pain ( 5 ). It has been estimated that SARS-CoV-2 targets human ACE-2 receptors, indicating a significant surface interaction with a high-affinity binding capacity ( 6 ). Immunization is considered a reliable prevention method to tackle infectious illnesses through the induction of active adaptive immunity ( 7 ). The body initiates an immune defense against foreign antigens introduced by the vaccine, with B-cells turning into memory cells after infection ( 8 ). Immunoglobulin M (IgM) levels increase within the first two weeks of the viral infection, peaking on the 13th day. After three weeks, Immunoglobulin (IgG) production begins, lasting nearly six months ( 9 ). The COVID-19 disease was first reported in China in December 2019, and the US Food and Drug Administration (FDA) and the World Health Organization (WHO) introduced COVID-19 vaccinations in September 2020 ( 10 ). Although the COVID-19 vaccine production process is complex due to the unstable dynamic change in the antigenicity of the virus ( 11 ), the COVID-19 vaccination process has significantly increased lately. During the past two years, several highly effective COVID-19 vaccines have been developed, including Pfizer BioNTech, Sinopharm, and Oxford-AstraZeneca. Pfizer BioNTech is an mRNA-based vaccine produced in Germany and the USA ( 12 ). Sinopharm is an inactivated virus vaccine with three doses ( 13 ), and Oxford-AstraZeneca is a three-dose vaccine derived from a mammal chimpanzee, produced in the UK and Sweden ( 14 ). The COVID-19 Vaccines played a crucial role in preventing the spread of SARS-CoV-2 by triggering the production of antibodies that recognize the spiked proteins of the virus and prevent future infections ( 15 ). All the developed COVID-19 vaccines induced immunoglobulin production against SARS-CoV-2. BioNTech vaccine, tested on numerous individuals, demonstrated high efficiency (> 90%) compared to other vaccines, while AstraZeneca vaccine was shown to be effective against the variants of the virus, including alpha, gamma, beta, and delta versions ( 16 ). However, there is a lack of evidence about the duration of preventive immunity after COVID-19 vaccination. Consequently, the purpose of this research is to find out how long the protective effects of the COVID-19 vaccine last based on the IgG titer test. Patients and Methods Study Design The prospective study was conducted in Sulaimani City, Kurdistan region-Iraq; involving 49 healthcare staff of Hiwa Hospital for Cancer. The collected personal information included gender, age, number of COVID-19 vaccination doses, and previous exposures to COVID-19 infection. In the meantime, blood samples were taken from the participants who received the Pfizer-BioNTech COVID-19 vaccine (received 2–3 doses of 30 micrograms each, administered intramuscularly, 21 days apart) and then the blood was sent to Komar University of Science and Technology for analysis. Oral personal consents were obtained from the participants and they were ensured that the collected data were only used for research purposes. IgG and IgM Measurements The IgG and IgM antibodies were detected by using a qualitative/quantitative immuno-assay (AESKULISA® SARS-cov-2 S1 ELISA kit) to determine the levels of IgG and IgM antibodies in the participant's serum. A qualitative assessment was conducted, followed by using 100µl of the participant's serum in the framework. The plates were incubated for 30 minutes at room temperature. Afterwards, the BIOTEK ELX50 microplate washer was used to take out 300µl of washing buffer and rinse the solution. Following that, a 100µl of the conjugate solution was applied to each well of the plate. The incubation period was extended by half an hour at room temperature for the frame housing the conjugate-filled wells. Roughly 300 microliters of washing buffer were added again after the solution had been removed. Then, the substrate solution was added to the wells and they were allowed to incubate at room temperature, away from light and humidity, for another thirty minutes before being removed. After that, the wells were filled with the substrate solution and left to incubate at room temperature, away from light and humidity, for an additional half an hour. The solution was also allowed to settle for five minutes after adding 100µl of stop solution. The BIOTEK ELX800 microplate reader and Biotek Gen5 Data Analysis Software were used to measure the optical density within thirty minutes at 450/620 nm. The quantitative calculation was done according to the AESKULISA® SARS-cov-2 S1 kit protocol. The samples below 1.00 gm/L of antibody were recognized as negative and positive ones were above 1.00 gm/L. Statistical Analysis The results were expressed as mean and percentages. A P-value of < 0.05 was considered statistically significant. For analyzing data, the software IBM SPSS Statistics 25.0 was used. Results This study included forty-eight healthcare participants, of whom 31 (63.5%) were males and 18 (36.7%) were females. Their mean age was 38.9 ± 10.29 and ranged from 20 to 62 years. The categorized age groups are shown in Table 1 . Table 1 The age group of the participants Age Group Number of Patients % 20–29 9 18.4 30–39 18 36.7 40–49 12 24.5 50–59 10 20.4 > 60 0 0 Total 49 100 The correlation between the frequency of SARS-CoV-2 infections among the participants and the mean titer of their IgM was also investigated (Table 2 ). Most individuals experienced COVID-19 once or twice, comprising 65.3% of the participants. Those with no infection history showed a slightly higher mean of IgM titer (1.15 gm/L) compared to those who had previously infected, whose titer ranged between 0.55 and 0.57 gm/L. Table 2 The correlation between the frequencies of SARS-COV-2 infection and the mean titer of IgM. Frequency of COVID-19 infection Number of individuals with previous infection Valid % Mean IgM antibodies (gm/L) 0 11 22.4 1.15 1 17 34.7 0.56 2 15 30.6 0.56 3 1 2.0 0.55 4 4 8.2 0.55 5 1 2.0 0.57 Total 49 100 Table 3 indicates the number of doses of the vaccination that each participant received; 85.7% received two doses, while 10.2% received three. A mere two people, or 4.1% of the total, were vaccinated with only one shot. Table 3 The number of vaccine doses received by the participants. Vaccine Doses Frequency Valid % 1 2 4.1 2 42 85.7 3 5 10.2 Total 49 100 In addition, a satisfactory response after six, twelve, and eighteen months, a sustained IgG antibody titer of 12.5, 13.45, and 13.8 gm/L were observed., respectively. However, it is statistically non-significant despite a slight increase in titer and sustainability of IgG with time after the vaccination, as shown in Table 4 . Table 4 The mean titer of IgG antibodies following the last received vaccine dose. Time after the last received dose Mean IgG level (gm/L) 6 Months 12.5 6–12 Months 13.45 13–18 Months 13.8 There was a slight difference in the COVID-19 immunity response between males and females, whereas it is statistically insignificant with a P-value of 0.7 (Fig. 1 ). On average, 10 months after the last dose of vaccination, the IgG titer in men was 12.21 gm/L and in females it was 11.41 gm/L. However, both males and females showed very low (negative) IgM titers. Discussion One of the optimum approaches to COVID-19 infection is vaccination. However, the available data regarding COVID-19 is limited as it is considered to be a new vaccine. Thus, we investigated the effect of the COVID-19 vaccine and the sustainability of antibodies (IgM) against SARS-CoV-2 antibodies among healthcare staff at Hiwa Hospital for Cancer in Sulaimani City, Kurdistan region- Iraq. The participants involved in this study had an ideal age range (20–60) for representing COVID-19 immunity in the general population and both genders were taken part. The participants were also healthy and had no serious medical disease. A study already revealed that age didn't affect immunological response to the COVID-19 vaccine ( 17 ). The mean titer of IgM was positive (1.15 gm/L) in 22.4% of participants, who were not infected (22.4%). This may suggest that these participants have recently been exposed to the virus without showing clinical signs and symptoms of the disease. In contrast, the participants who had previously confirmed COVID-19 showed negative IgM titers. These findings corroborate those of Ali et al ( 18 ), who found that those who had been vaccinated against COVID-19 had a long-lasting antibodies against SARS-CoV-2. Regarding the post-vaccination sustainability of IgG, it was seen that the IgG titer increased with increasing the time after vaccination (12.5 gm/L after 6 months; 13.45 g/L after 12 months; 13.8 gm/L after 18 months). However, it was not statistically significant. This indicates that the COVID-19 vaccine supports sustainable production of SARS-CoV-2 immunoglobulins at the optimal rate for at least 18 months. These findings are consistent with a study, conducted by Alzaabi et al ( 9 ), who claimed that a steady increase in antibodies and positive IgG titers within the first five months is sufficient to reduce the risk of reinfection. Furthermore, the data showed a slight difference, but insignificant, in IgG production according to gender, higher in males than females. This might be because some female individuals have a shorter period between vaccination and IgG analysis, so they showed a lower titer of IgG or another explanation could be that males initially take a longer time to produce antibodies, which will last for a longer period after vaccination compared to females, who have quick response to produce antibodies and shorter period of antibody sustainability( 19 ). Consistently, Ishaq et al ( 20 ) observed a non-significant difference between males and females in terms of IgG and IgM production following COVID-19 vaccination. This study also investigated the common side effects of the vaccine and showed that 59.18% of the individuals experienced headaches, fever, malaise, and other symptoms. However, 40.82% had not experienced any of the mentioned symptoms. The limitation of the present study is the small size of the participants, so further studies in a larger group of vaccinated individuals for longer post-vaccination periods are recommended. Conclusion To conclude, this study demonstrated that the COVID-19 vaccine is effective in enhancing immune response against SARS-CoV-2. It further proves that there is no correlation between age or gender and that IgG titer rises linearly with time. It was also found the COVID-19 vaccine provides a preventive level of IgG for at least 18 months; this may efficiently reduce morbidity, hospitalization, and mortality in populations. Abbreviations Angiotensin-converting enzyme receptor 2 (ACE-2), Immunoglobulin M (IgM), Immunoglobulin (IgG), Food and Drug Administration (FDA), World Health Organization (WHO). Declarations Acknowledgments We want to express our sincere acknowledgments to the staff of the laboratory center of Hiwa Hospital for Cancer located in Sulaymani City who assisted us in the process of data collection and sample storage. Author Contribution N-SK designed the study, L-AM, and S-JA, contributed equally to the sample collection. N-SK, K-RS, and D-DG analyzed the data. R-MK revised and composed the manuscript. All authors read and approved the final manuscript. Funding No financial support was obtained during this study. Availability of data and materials The datasets generated and/or analysed during the current study are not publicly available but are available from the corresponding author on reasonable request. Ethics approval and consent to participate This study was approved by the Ethical Committee of Hiwa Hospital. The typical requirement for oral consent was achieved, participants were apprised of their right to discontinue participation in the study at any time. Consent for publication All authors read and approved the final manuscript. Competing interests The authors declare that they have no known competing financial or personal interests that could influence the work reported in this manuscript. References Dong E, Du H, Gardner L. An interactive web-based dashboard to track COVID-19 in real-time. Vol. 20, The Lancet Infectious Diseases. Lancet Publishing Group; 2020. p. 533–4. Wrapp D, Wang N, Corbett KS, Goldsmith JA, Hsieh CL, Abiona O, et al. Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation [Internet]. 2019. Available from: https://www.science.org Mohamadian M, Chiti H, Shoghli A, Biglari S, Parsamanesh N, Esmaeilzadeh A. COVID-19: Virology, biology and novel laboratory diagnosis. Vol. 23, Journal of Gene Medicine. Blackwell Publishing Inc.; 2021. Albini A, Di Guardo G, Noonan DMC, Lombardo M. The SARS-CoV-2 receptor, ACE-2, is expressed on many different cell types: implications for ACE-inhibitor- and angiotensin II receptor blocker-based cardiovascular therapies. Intern Emerg Med. 2020 Aug 1;15(5):759–66. Balachandar V, Mahalaxmi I, Subramaniam M, Kaavya J, Senthil Kumar N, Laldinmawii G, et al. Follow-up studies in COVID-19 recovered patients - is it mandatory? Vol. 729, Science of the Total Environment. Elsevier B.V.; 2020. Shirbhate E, Pandey J, Patel VK, Kamal M, Jawaid T, Gorain B, et al. Understanding the role of ACE-2 receptor in the pathogenesis of COVID-19 disease: a potential approach for therapeutic intervention. Vol. 73, Pharmacological Reports. Springer Science and Business Media Deutschland GmbH; 2021. p. 1539–50. Pollard AJ, Bijker EM. A guide to vaccinology: from basic principles to new developments. Vol. 21, Nature Reviews Immunology. Nature Research; 2021. p. 83–100. Bugya Z, Prechl J, Szénási T, Nemes É, Bácsi A, Koncz G. Multiple levels of immunological memory and their association with vaccination. Vaccines (Basel). 2021 Feb 1;9(2):1–25. Alzaabi AH, Ahmed LA, Rabooy AE, Zaabi A Al, Alkaabi M, AlMahmoud F, et al. Longitudinal changes in IgG levels among COVID-19 recovered patients: A prospective cohort study. PLoS One. 2021 Jun 1;16(6 June 2021). Kaur SP, Gupta V. COVID-19 Vaccine: A comprehensive status report. Vol. 288, Virus Research. Elsevier B.V.; 2020. Heinz FX, Stiasny K. Distinguishing features of current COVID-19 vaccines: knowns and unknowns of antigen presentation and modes of action. Vol. 6, npj Vaccines. Nature Research; 2021. Lewis LM, Badkar A V., Cirelli D, Combs R, Lerch TF. The Race to Develop the Pfizer-BioNTech COVID-19 Vaccine: From the Pharmaceutical Scientists’ Perspective. Vol. 112, Journal of Pharmaceutical Sciences. Elsevier B.V.; 2023. p. 640–7. Fan Y, Chan KH, Hung IFN. Safety and efficacy of COVID-19 vaccines: A systematic review and meta-analysis of different vaccines at phase 3. Vol. 9, Vaccines. MDPI; 2021. Mascellino MT, Di Timoteo F, De Angelis M, Oliva A. Overview of the main anti-sars-cov-2 vaccines: Mechanism of action, efficacy, and safety. Vol. 14, Infection and Drug Resistance. Dove Medical Press Ltd; 2021. p. 3459–76. Peng XL, Cheng JSY, Gong HL, Yuan M Di, Zhao XH, Li Z, et al. Advances in the design and development of SARS-CoV-2 vaccines. Vol. 8, Military Medical Research. BioMed Central Ltd; 2021. Fiolet T, Kherabi Y, MacDonald CJ, Ghosn J, Peiffer-Smadja N. Comparing COVID-19 vaccines for their characteristics, efficacy, and effectiveness against SARS-CoV-2 and variants of concern: a narrative review. Vol. 28, Clinical Microbiology and Infection. Elsevier B.V.; 2022. p. 202–21. Kadali RAK, Janagama R, Peruru S, Malayala S V. Side effects of BNT162b2 mRNA COVID-19 vaccine: A randomized, cross-sectional study with detailed self-reported symptoms from healthcare workers. International Journal of Infectious Diseases. 2021 May 1;106:376–81. Ali H, Alahmad B, Al-Shammari AA, Alterki A, Hammad M, Cherian P, et al. Previous COVID-19 Infection and Antibody Levels After Vaccination. Front Public Health. 2021 Dec 1;9. Salvagno GL, Henry BM, Di Piazza G, Pighi L, De Nitto S, Bragantini D, et al. Anti-sars-cov-2 receptor-binding domain total antibodies response in seropositive and seronegative healthcare workers undergoing covid-19 mrna bnt162b2 vaccination. Diagnostics. 2021 May 4;11(5). Ishaq SE, Abdulqadir SZ, khudhur ZO, Omar SA, Qadir MK, Awla H khdir, et al. Comparative study of SARS-CoV-2 antibody titers between male and female COVID-19 patients living in Kurdistan region of Iraq. Gene Rep. 2021 Dec 1;25. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3834361","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":265357237,"identity":"299faa58-fc36-4f96-b70c-1dd7f14016d0","order_by":0,"name":"Najmaddin S.H. 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SARS-COV-2 is a member of the Coronaviridae family with a genetic material of RNA (+\u0026thinsp;ssRNA). The 3'-end of the viral genome encodes four structural proteins: spike (S), nucleocapsid (N), envelope (E), and membrane (M). The spike proteins are immunogenic and enhance the pathogenic effects of the virus (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). The virus enters pneumocytes through angiotensin-converting enzyme receptor 2 (ACE-2), causing acute respiratory syndrome (viral pneumonia). The virus uses spikes to connect to respiratory cells, binding to ACE-2 in kidneys, lungs, endothelial cells, liver, and blood vessels (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). ACE-2 facilitates protein cleavage, causing the virus to reproduce and burst cells, causing symptoms like sore throat, fever, and muscle pain (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). It has been estimated that SARS-CoV-2 targets human ACE-2 receptors, indicating a significant surface interaction with a high-affinity binding capacity (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eImmunization is considered a reliable prevention method to tackle infectious illnesses through the induction of active adaptive immunity (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). The body initiates an immune defense against foreign antigens introduced by the vaccine, with B-cells turning into memory cells after infection (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). Immunoglobulin M (IgM) levels increase within the first two weeks of the viral infection, peaking on the 13th day. After three weeks, Immunoglobulin (IgG) production begins, lasting nearly six months (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe COVID-19 disease was first reported in China in December 2019, and the US Food and Drug Administration (FDA) and the World Health Organization (WHO) introduced COVID-19 vaccinations in September 2020 (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Although the COVID-19 vaccine production process is complex due to the unstable dynamic change in the antigenicity of the virus (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e), the COVID-19 vaccination process has significantly increased lately. During the past two years, several highly effective COVID-19 vaccines have been developed, including Pfizer BioNTech, Sinopharm, and Oxford-AstraZeneca. Pfizer BioNTech is an mRNA-based vaccine produced in Germany and the USA (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). Sinopharm is an inactivated virus vaccine with three doses (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e), and Oxford-AstraZeneca is a three-dose vaccine derived from a mammal chimpanzee, produced in the UK and Sweden (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe COVID-19 Vaccines played a crucial role in preventing the spread of SARS-CoV-2 by triggering the production of antibodies that recognize the spiked proteins of the virus and prevent future infections (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e). All the developed COVID-19 vaccines induced immunoglobulin production against SARS-CoV-2. BioNTech vaccine, tested on numerous individuals, demonstrated high efficiency (\u0026gt;\u0026thinsp;90%) compared to other vaccines, while AstraZeneca vaccine was shown to be effective against the variants of the virus, including alpha, gamma, beta, and delta versions (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). However, there is a lack of evidence about the duration of preventive immunity after COVID-19 vaccination. Consequently, the purpose of this research is to find out how long the protective effects of the COVID-19 vaccine last based on the IgG titer test.\u003c/p\u003e"},{"header":"Patients and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Design\u003c/h2\u003e \u003cp\u003eThe prospective study was conducted in Sulaimani City, Kurdistan region-Iraq; involving 49 healthcare staff of Hiwa Hospital for Cancer. The collected personal information included gender, age, number of COVID-19 vaccination doses, and previous exposures to COVID-19 infection. In the meantime, blood samples were taken from the participants who received the Pfizer-BioNTech COVID-19 vaccine (received 2\u0026ndash;3 doses of 30 micrograms each, administered intramuscularly, 21 days apart) and then the blood was sent to Komar University of Science and Technology for analysis. Oral personal consents were obtained from the participants and they were ensured that the collected data were only used for research purposes.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eIgG and IgM Measurements\u003c/h2\u003e \u003cp\u003eThe IgG and IgM antibodies were detected by using a qualitative/quantitative immuno-assay (AESKULISA\u0026reg; SARS-cov-2 S1 ELISA kit) to determine the levels of IgG and IgM antibodies in the participant's serum. A qualitative assessment was conducted, followed by using 100\u0026micro;l of the participant's serum in the framework. The plates were incubated for 30 minutes at room temperature. Afterwards, the BIOTEK ELX50 microplate washer was used to take out 300\u0026micro;l of washing buffer and rinse the solution. Following that, a 100\u0026micro;l of the conjugate solution was applied to each well of the plate. The incubation period was extended by half an hour at room temperature for the frame housing the conjugate-filled wells. Roughly 300 microliters of washing buffer were added again after the solution had been removed. Then, the substrate solution was added to the wells and they were allowed to incubate at room temperature, away from light and humidity, for another thirty minutes before being removed. After that, the wells were filled with the substrate solution and left to incubate at room temperature, away from light and humidity, for an additional half an hour. The solution was also allowed to settle for five minutes after adding 100\u0026micro;l of stop solution. The BIOTEK ELX800 microplate reader and Biotek Gen5 Data Analysis Software were used to measure the optical density within thirty minutes at 450/620 nm. The quantitative calculation was done according to the AESKULISA\u0026reg; SARS-cov-2 S1 kit protocol. The samples below 1.00 gm/L of antibody were recognized as negative and positive ones were above 1.00 gm/L.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eThe results were expressed as mean and percentages. A P-value of \u0026lt;\u0026thinsp;0.05 was considered statistically significant. For analyzing data, the software IBM SPSS Statistics 25.0 was used.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThis study included forty-eight healthcare participants, of whom 31 (63.5%) were males and 18 (36.7%) were females. Their mean age was 38.9\u0026thinsp;\u0026plusmn;\u0026thinsp;10.29 and ranged from 20 to 62 years. The categorized age groups are shown in Table\u0026nbsp;\u003cspan\u003e1\u003c/span\u003e.\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 1\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe age group of the participants\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"3\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAge Group\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNumber of Patients\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20\u0026ndash;29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u0026ndash;39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40\u0026ndash;49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50\u0026ndash;59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026gt;\u0026thinsp;60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTotal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe correlation between the frequency of SARS-CoV-2 infections among the participants and the mean titer of their IgM was also investigated (Table\u0026nbsp;\u003cspan\u003e2\u003c/span\u003e). Most individuals experienced COVID-19 once or twice, comprising 65.3% of the participants. Those with no infection history showed a slightly higher mean of IgM titer (1.15 gm/L) compared to those who had previously infected, whose titer ranged between 0.55 and 0.57 gm/L.\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 2\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe correlation between the frequencies of SARS-COV-2 infection and the mean titer of IgM.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"4\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFrequency of\u003c/p\u003e\n \u003cp\u003eCOVID-19 infection\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNumber of individuals with previous infection\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eValid %\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMean IgM antibodies\u003c/p\u003e\n \u003cp\u003e(gm/L)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e22.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.15\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e34.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.56\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.56\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.55\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.55\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.57\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTotal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\n\u003c/div\u003e\n\u003cp\u003eTable\u0026nbsp;\u003cspan\u003e3\u003c/span\u003e indicates the number of doses of the vaccination that each participant received; 85.7% received two doses, while 10.2% received three. A mere two people, or 4.1% of the total, were vaccinated with only one shot.\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 3\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe number of vaccine doses received by the participants.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"3\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eVaccine Doses\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFrequency\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eValid %\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e85.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTotal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eIn addition, a satisfactory response after six, twelve, and eighteen months, a sustained IgG antibody titer of 12.5, 13.45, and 13.8 gm/L were observed., respectively. However, it is statistically non-significant despite a slight increase in titer and sustainability of IgG with time after the vaccination, as shown in Table\u0026nbsp;\u003cspan\u003e4\u003c/span\u003e.\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable id=\"Tab5\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 4\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe mean titer of IgG antibodies following the last received vaccine dose.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"2\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTime after the last received dose\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMean IgG level (gm/L)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6 Months\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u0026ndash;12 Months\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13.45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13\u0026ndash;18 Months\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13.8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\n\u003c/div\u003e\n\u003cp\u003eThere was a slight difference in the COVID-19 immunity response between males and females, whereas it is statistically insignificant with a P-value of 0.7 (Fig.\u0026nbsp;\u003cspan\u003e1\u003c/span\u003e). On average, 10 months after the last dose of vaccination, the IgG titer in men was 12.21 gm/L and in females it was 11.41 gm/L. However, both males and females showed very low (negative) IgM titers.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eOne of the optimum approaches to COVID-19 infection is vaccination. However, the available data regarding COVID-19 is limited as it is considered to be a new vaccine. Thus, we investigated the effect of the COVID-19 vaccine and the sustainability of antibodies (IgM) against SARS-CoV-2 antibodies among healthcare staff at Hiwa Hospital for Cancer in Sulaimani City, Kurdistan region- Iraq.\u003c/p\u003e \u003cp\u003eThe participants involved in this study had an ideal age range (20\u0026ndash;60) for representing COVID-19 immunity in the general population and both genders were taken part. The participants were also healthy and had no serious medical disease. A study already revealed that age didn't affect immunological response to the COVID-19 vaccine (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e). The mean titer of IgM was positive (1.15 gm/L) in 22.4% of participants, who were not infected (22.4%). This may suggest that these participants have recently been exposed to the virus without showing clinical signs and symptoms of the disease. In contrast, the participants who had previously confirmed COVID-19 showed negative IgM titers. These findings corroborate those of Ali et al (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e), who found that those who had been vaccinated against COVID-19 had a long-lasting antibodies against SARS-CoV-2.\u003c/p\u003e \u003cp\u003eRegarding the post-vaccination sustainability of IgG, it was seen that the IgG titer increased with increasing the time after vaccination (12.5 gm/L after 6 months; 13.45 g/L after 12 months; 13.8 gm/L after 18 months). However, it was not statistically significant. This indicates that the COVID-19 vaccine supports sustainable production of SARS-CoV-2 immunoglobulins at the optimal rate for at least 18 months. These findings are consistent with a study, conducted by Alzaabi \u003cem\u003eet al\u003c/em\u003e (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e), who claimed that a steady increase in antibodies and positive IgG titers within the first five months is sufficient to reduce the risk of reinfection.\u003c/p\u003e \u003cp\u003eFurthermore, the data showed a slight difference, but insignificant, in IgG production according to gender, higher in males than females. This might be because some female individuals have a shorter period between vaccination and IgG analysis, so they showed a lower titer of IgG or another explanation could be that males initially take a longer time to produce antibodies, which will last for a longer period after vaccination compared to females, who have quick response to produce antibodies and shorter period of antibody sustainability(\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e). Consistently, Ishaq et al (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e) observed a non-significant difference between males and females in terms of IgG and IgM production following COVID-19 vaccination.\u003c/p\u003e \u003cp\u003eThis study also investigated the common side effects of the vaccine and showed that 59.18% of the individuals experienced headaches, fever, malaise, and other symptoms. However, 40.82% had not experienced any of the mentioned symptoms. The limitation of the present study is the small size of the participants, so further studies in a larger group of vaccinated individuals for longer post-vaccination periods are recommended.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eTo conclude, this study demonstrated that the COVID-19 vaccine is effective in enhancing immune response against SARS-CoV-2. It further proves that there is no correlation between age or gender and that IgG titer rises linearly with time. It was also found the COVID-19 vaccine provides a preventive level of IgG for at least 18 months; this may efficiently reduce morbidity, hospitalization, and mortality in populations.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eAngiotensin-converting enzyme receptor 2 (ACE-2), Immunoglobulin M (IgM), Immunoglobulin (IgG), Food and Drug Administration (FDA), World Health Organization (WHO).\u003c/p\u003e\n"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe want to express our sincere acknowledgments to the staff of the laboratory center of Hiwa Hospital for Cancer located in Sulaymani City who assisted us in the process of data collection and sample storage.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eN-SK designed the study, L-AM, and S-JA, contributed equally to the sample collection. N-SK, K-RS, and D-DG analyzed the data. R-MK revised and composed the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo financial support was obtained during this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analysed during the current study are not publicly available but are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Ethical Committee of Hiwa Hospital. The typical requirement for oral consent was achieved, participants were apprised of their right to discontinue participation in the study at any time.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial or personal interests that could influence the work reported in this manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eDong E, Du H, Gardner L. An interactive web-based dashboard to track COVID-19 in real-time. Vol. 20, The Lancet Infectious Diseases. Lancet Publishing Group; 2020. p. 533\u0026ndash;4. \u003c/li\u003e\n\u003cli\u003eWrapp D, Wang N, Corbett KS, Goldsmith JA, Hsieh CL, Abiona O, et al. Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation [Internet]. 2019. Available from: https://www.science.org\u003c/li\u003e\n\u003cli\u003eMohamadian M, Chiti H, Shoghli A, Biglari S, Parsamanesh N, Esmaeilzadeh A. COVID-19: Virology, biology and novel laboratory diagnosis. Vol. 23, Journal of Gene Medicine. Blackwell Publishing Inc.; 2021. \u003c/li\u003e\n\u003cli\u003eAlbini A, Di Guardo G, Noonan DMC, Lombardo M. The SARS-CoV-2 receptor, ACE-2, is expressed on many different cell types: implications for ACE-inhibitor- and angiotensin II receptor blocker-based cardiovascular therapies. Intern Emerg Med. 2020 Aug 1;15(5):759\u0026ndash;66. \u003c/li\u003e\n\u003cli\u003eBalachandar V, Mahalaxmi I, Subramaniam M, Kaavya J, Senthil Kumar N, Laldinmawii G, et al. Follow-up studies in COVID-19 recovered patients - is it mandatory? Vol. 729, Science of the Total Environment. Elsevier B.V.; 2020. \u003c/li\u003e\n\u003cli\u003eShirbhate E, Pandey J, Patel VK, Kamal M, Jawaid T, Gorain B, et al. Understanding the role of ACE-2 receptor in the pathogenesis of COVID-19 disease: a potential approach for therapeutic intervention. Vol. 73, Pharmacological Reports. Springer Science and Business Media Deutschland GmbH; 2021. p. 1539\u0026ndash;50. \u003c/li\u003e\n\u003cli\u003ePollard AJ, Bijker EM. A guide to vaccinology: from basic principles to new developments. Vol. 21, Nature Reviews Immunology. Nature Research; 2021. p. 83\u0026ndash;100. \u003c/li\u003e\n\u003cli\u003eBugya Z, Prechl J, Sz\u0026eacute;n\u0026aacute;si T, Nemes \u0026Eacute;, B\u0026aacute;csi A, Koncz G. Multiple levels of immunological memory and their association with vaccination. Vaccines (Basel). 2021 Feb 1;9(2):1\u0026ndash;25. \u003c/li\u003e\n\u003cli\u003eAlzaabi AH, Ahmed LA, Rabooy AE, Zaabi A Al, Alkaabi M, AlMahmoud F, et al. Longitudinal changes in IgG levels among COVID-19 recovered patients: A prospective cohort study. PLoS One. 2021 Jun 1;16(6 June 2021). \u003c/li\u003e\n\u003cli\u003eKaur SP, Gupta V. COVID-19 Vaccine: A comprehensive status report. Vol. 288, Virus Research. Elsevier B.V.; 2020. \u003c/li\u003e\n\u003cli\u003eHeinz FX, Stiasny K. Distinguishing features of current COVID-19 vaccines: knowns and unknowns of antigen presentation and modes of action. Vol. 6, npj Vaccines. Nature Research; 2021. \u003c/li\u003e\n\u003cli\u003eLewis LM, Badkar A V., Cirelli D, Combs R, Lerch TF. The Race to Develop the Pfizer-BioNTech COVID-19 Vaccine: From the Pharmaceutical Scientists\u0026rsquo; Perspective. Vol. 112, Journal of Pharmaceutical Sciences. Elsevier B.V.; 2023. p. 640\u0026ndash;7. \u003c/li\u003e\n\u003cli\u003eFan Y, Chan KH, Hung IFN. Safety and efficacy of COVID-19 vaccines: A systematic review and meta-analysis of different vaccines at phase 3. Vol. 9, Vaccines. MDPI; 2021. \u003c/li\u003e\n\u003cli\u003eMascellino MT, Di Timoteo F, De Angelis M, Oliva A. Overview of the main anti-sars-cov-2 vaccines: Mechanism of action, efficacy, and safety. Vol. 14, Infection and Drug Resistance. Dove Medical Press Ltd; 2021. p. 3459\u0026ndash;76. \u003c/li\u003e\n\u003cli\u003ePeng XL, Cheng JSY, Gong HL, Yuan M Di, Zhao XH, Li Z, et al. Advances in the design and development of SARS-CoV-2 vaccines. Vol. 8, Military Medical Research. BioMed Central Ltd; 2021. \u003c/li\u003e\n\u003cli\u003eFiolet T, Kherabi Y, MacDonald CJ, Ghosn J, Peiffer-Smadja N. Comparing COVID-19 vaccines for their characteristics, efficacy, and effectiveness against SARS-CoV-2 and variants of concern: a narrative review. Vol. 28, Clinical Microbiology and Infection. Elsevier B.V.; 2022. p. 202\u0026ndash;21. \u003c/li\u003e\n\u003cli\u003eKadali RAK, Janagama R, Peruru S, Malayala S V. Side effects of BNT162b2 mRNA COVID-19 vaccine: A randomized, cross-sectional study with detailed self-reported symptoms from healthcare workers. International Journal of Infectious Diseases. 2021 May 1;106:376\u0026ndash;81. \u003c/li\u003e\n\u003cli\u003eAli H, Alahmad B, Al-Shammari AA, Alterki A, Hammad M, Cherian P, et al. Previous COVID-19 Infection and Antibody Levels After Vaccination. Front Public Health. 2021 Dec 1;9. \u003c/li\u003e\n\u003cli\u003eSalvagno GL, Henry BM, Di Piazza G, Pighi L, De Nitto S, Bragantini D, et al. Anti-sars-cov-2 receptor-binding domain total antibodies response in seropositive and seronegative healthcare workers undergoing covid-19 mrna bnt162b2 vaccination. Diagnostics. 2021 May 4;11(5). \u003c/li\u003e\n\u003cli\u003eIshaq SE, Abdulqadir SZ, khudhur ZO, Omar SA, Qadir MK, Awla H khdir, et al. Comparative study of SARS-CoV-2 antibody titers between male and female COVID-19 patients living in Kurdistan region of Iraq. Gene Rep. 2021 Dec 1;25. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"SARS-CoV-2, COVID-19, Vaccination, Pfizer","lastPublishedDoi":"10.21203/rs.3.rs-3834361/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3834361/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThe SARS-CoV-2 outbreak caused pneumonia and respiratory distress worldwide in December 2019. It was later recognized as the COVID-19 pandemic, so COVID-19 specific vaccines were soon developed and used for immunization of global communities. The primary objective of this study is to measure the concentration and persistence of IgG antibodies against SARS-CoV-2in healthcare employees of Hiwa Hospital for Cancer in Sulaimani City, Iraq.\u003c/p\u003e\u003ch2\u003ePatients and Methods\u003c/h2\u003e \u003cp\u003e: Blood samples were collected from 49 healthcare employees in Hiwa Hospital who received the Pfizer-BioNTech COVID-19 vaccine. The participants were recruited through a questionnaire containing information about age, gender, number of vaccination doses, and frequency of previous COVID-19 infections. The anti- COVID-19 antibodies in the blood samples were analyzed using the ELISA technique.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe age of the participants ranged from 30 to 39 years old (mean 38.9\u0026thinsp;\u0026plusmn;\u0026thinsp;10.29), with 31 (63.5%) being males and 18 (36.7%) being females. The anti COVID-19 specific IgG titers were 12.5, 13.45, and 13.8 mg/dL after 6, 12 and 18 months of vaccination, respectively. Besides, 10.2% of the participants have received three doses of the vaccines, 85.7% have received two doses, and only (4.1%) received a single dose. Moreover, a faction (22.4%) of the participants had a very low positive titer of anti COVID-19 specific IgM without obvious signs and symptoms of the disease.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThe Immunoglobulin G antibody titer against COVID-19 remains at a protective level for at least eighteen months.\u003c/p\u003e","manuscriptTitle":"Assessment of Longevity of COVID-19 Vaccination Among Hematology Healthcare Workers","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-01-08 19:30:26","doi":"10.21203/rs.3.rs-3834361/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"24b50809-52c3-4782-a564-175185633183","owner":[],"postedDate":"January 8th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-01-10T14:16:27+00:00","versionOfRecord":[],"versionCreatedAt":"2024-01-08 19:30:26","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3834361","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3834361","identity":"rs-3834361","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}