Hemoglobin changes in Covid-19 patients with and without a history of influenza vaccination

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This study aimed to compare the clinical and laboratory findings in COVID-19 patients with and without a history of influenza vaccination. Methods: This study was a comparative analytical study. A total of 60 hospitalized patients from Ferdows Hospital and Behlool Gonabad Hospital were selected based on inclusion criteria and a convenience sampling method. Data collection involved demographic information, clinical symptom forms, and laboratory test results. Data analysis was performed using SPSS version 18. Results: Findings showed that COVID-19 patients with a history of influenza vaccination had less severe clinical symptoms, with fewer individuals experiencing severe symptoms. However, this difference was not statistically significant. A statistically significant difference (P = .020) was found between the two groups regarding hemoglobin changes, with a greater decrease in hemoglobin levels observed in the unvaccinated group. Comparison of CRP, WBC, and platelet counts between the two groups revealed no statistically significant differences (P > .05). Conclusions: The results of this study suggest that a history of influenza vaccination influences changes in hemoglobin levels in COVID-19 patients. Given that COVID-19 vaccination is not universally accepted and there is no mandatory vaccination policy, and considering the established impact of reduced hemoglobin levels on the severity and outcomes of COVID-19, influenza vaccination is recommended to prevent complications. Health sciences/Health care Health sciences/Medical research COVID-19 SARS-CoV-2 Influenza Vaccination Hemoglobin Clinical Symptoms Laboratory Symptoms Introduction Although the COVID-19 public health emergency has ended, thousands of COVID-19-related hospitalizations and hundreds of COVID-19-related deaths still occur weekly [ 1 ]. COVID-19 infection is a viral infection that primarily targets the respiratory system [ 2 ]. The unprecedented global impact of COVID-19 led to the rapid development and deployment of vaccines against the virus, including those using new mRNA technology [ 3 ]. Walter states that the ultimate goal is to provide high levels of vaccination coverage during the anticipated periods of influenza and COVID-19 virus transmission, protecting those at higher risk. The influenza vaccine is administered annually to high-risk individuals. Additionally, vaccines were developed in response to the COVID-19 pandemic, which became available for the first time in December 2020 [ 4 ]. However, the widespread availability of COVID-19 vaccines occurred in the fall of 2022, when they were recommended alongside the seasonal influenza vaccine. The introduction of the bivalent mRNA COVID-19 vaccines coincided with the seasonal influenza vaccines in the fall of 2022 [ 5 ]. Despite the promising safety profiles and efficacy of mRNA vaccines in preventing severe COVID-19 outcomes, there has been significant public reluctance to get vaccinated globally. For example, in the United States, nearly 20% of the population has not received any dose of the COVID-19 vaccine. By May 4, 2024, 27.7% of the population in Israel had not received any COVID-19 vaccine. Among seniors aged 65 and older, vaccination coverage for the first and second COVID-19 booster shots was 82.6% and 47.8%, respectively. National influenza vaccine coverage was 15.3%, while 52.3–58.6% of the elderly population was vaccinated against influenza. One of the main reasons for COVID-19 vaccine hesitancy is safety concerns regarding the vaccine [ 3 ]. Furthermore, from a managerial perspective, there is still no standardized protocol for COVID-19 vaccination [ 2 ]. One of the pandemic management strategies focuses on the protective, therapeutic, and immune-boosting potentials [ 6 – 8 ]. Another reality that must be addressed is that COVID-19 vaccines need modification and updates to adapt to viral mutations for protection against COVID-19 infection [ 4 ]. Studies have shown that the number of COVID-19 vaccinations in each season continues to decline [ 1 ]. Respiratory viruses, including the coronavirus, pose a serious threat to global health security and can lead to high mortality and significant financial burdens for treatment [9]. The global spread of this disease has been a stark reminder that infectious diseases remain a persistent threat to human health, especially emerging and re-emerging diseases, which always pose a potential challenge to healthcare systems worldwide (10–13). COVID-19 infection can lead to severe outcomes, including death or admission to intensive care units (ICUs) [ 14 – 16 ]. However, the full clinical characteristics and outcomes of this disease are still not entirely known. Nevertheless, early studies conducted in China described a wide spectrum of the disease, from mild to severe, based on the patients’ age, underlying conditions, and mortality [17–20]. Since the global impact of this virus continues and the mutations in the virus cause additional problems, it is crucial to focus on alleviating and reducing symptoms of the disease and minimizing the associated burden and mortality. In other words, post-pandemic studies are necessary to identify effective strategies for symptom reduction, speeding up treatment and recovery, and reducing disease-related complications. It seems that existing vaccines for other respiratory viruses might be helpful in reducing the severity of COVID-19 [ 2 ]. As influenza, COVID-19, and other respiratory viruses typically peak in the winter months, individuals usually receive influenza and COVID-19 vaccines in late summer or early fall if they wish [ 4 ]. In Iran, influenza vaccination is provided to high-risk individuals or optionally to anyone who desires it, while COVID-19 vaccination is neither mandatory nor routine. Several studies have investigated the effects of influenza vaccination on various aspects of COVID-19, including outcomes, mortality, and hospitalization rates [21–30, 1–5], yielding varying results. Therefore, further evaluation seemed necessary. This study aimed to compare the clinical and laboratory findings in COVID-19 patients with and without a history of influenza vaccination. Methods Study design The present study is a comparative analytical study involving two groups. Sixty COVID-19 patients (30 per group) were compared in terms of hemoglobin changes, clinical symptoms, and laboratory findings between two groups with and without a history of influenza vaccination. Patients selected from Ferdows and Gonabad bohlool hospitals. Setting The study population included hospitalized patients from Ferdows and Gonabad bohlool hospitals in 2023–2024 who were diagnosed with COVID-19 based on a positive PCR test. Participants Sampling was performed using a convenience sampling method based on inclusion criteria. Inclusion Criteria: Patients who visited Ferdows and Gonabad hospitals with a positive PCR test for COVID-19 and who were willing to participate in the study. Data sources/ measurement Data were collected using a questionnaire with five sections: A)Demographic Information Form: including age, gender, marital status, occupation, education level. B) Risk Factors Form: including a history of cardiovascular, kidney, liver diseases, diabetes, hypertension, and lung diseases such as asthma. This form was filled out based on self-reporting by the patient. C) Clinical Symptoms Form: including fever, cough, shortness of breath, sore throat, muscle pain, fatigue, gastrointestinal disorders (diarrhea and vomiting), loss of smell, loss of taste, and vision disturbances (eye redness and tearing). D) Laboratory Symptoms Form: including CRP and CBC test results. E) Influenza Vaccination History: based on self-reporting, yes or no, and if yes, the date of vaccination. Study size The sample size was determined using G*Power version 3.1.9.2 with an effect size of 1.03, resulting in 22 participants per group and a total of 44 participants. To account for potential sample attrition, this number was increased to 30 participants per group. It should be noted that the effect size was derived from a pilot study, specifically for the hemoglobin variable, based on the mean and standard deviation of hemoglobin in the vaccinated group (14.8 ± 1.2) and the unvaccinated group (13.6 ± 1.12). Quantitative variables After obtaining ethical approval from the Medical University of Gonabad and presenting it to the relevant authorities at Ferdows and Gonabad hospitals, patients diagnosed with COVID-19 (positive PCR test) who met the inclusion criteria were included in the study using a convenience sampling method. For all hospitalized patients, demographic information, risk factors, and clinical symptoms forms were completed based on self-reporting by the patients, observations, and, in some cases, based on medical records. For discharged patients, the medical records were reviewed, and the relevant questionnaire was completed based on the information available and, if necessary, through a personal interview with the patient. The influenza vaccination history was recorded based on self-reporting, with the date of vaccination, if applicable. Ethical considerations in this study included obtaining informed consent from all participants, ensuring no physical or psychological harm from the intervention, commitment to reporting the results to the university, following the ethical guidelines of Gonabad University of Medical Sciences, and maintaining the confidentiality of all information. Statistical methods Data were analyzed using SPSS version 18. Descriptive statistics (frequency distribution tables, mean, and standard deviation) and inferential statistics (independent t-test and Chi-square test) were used. The Shapiro-Wilk test was used to determine the normality of quantitative variables. The significance level for all statistical tests was set at 0.05. Results The average age of the study participants was 48.81 ± 21.58 years. Of the 60 participants, 31 were male (51.6%), 27 (45%) had education below high school, 36 (60%) were married, 41 (68.3%) lived in urban areas, 18 (30%) had a freelance job, and 31 (51.6%) had no underlying diseases. The most common underlying disease among the participants was cardiovascular disease (37.4%). Seventy-one percent reported not smoking, and 93.3% reported not drinking alcohol. Thirty-eight percent had blood type B. According to the Chi-square test, no significant differences were found between the two groups regarding these variables (P > 0.05).The study results showed that the most common clinical symptoms in these patients were fever, cough, myalgia, weakness, and fatigue. The comparison of frequency of clinical symptoms including fever, cough, shortness of breath, sore throat, myalgia, weakness, fatigue, gastrointestinal symptoms, and sensory impairments (smell, taste, and vision) using the chi square test showed that in the influenza-vaccinated group, the symptoms were less severe, and fewer individuals experienced severe symptoms, although this difference was not statistically significant (P > 0.05) (Table 1). The comparison of laboratory symptoms indicated no significant differences between the two groups in CRP, WBC, and Platelet levels. However, the comparison of hemoglobin levels between the two groups revealed a significant difference, with a more pronounced decrease in hemoglobin in the group without a history of influenza vaccination (P = 0.042) (Table 2). Table no.1: comparison of clinical signs in two groups Signs Severity No flu vaccine Flu vaccine group Test result Fever No/ mild 9(30) 11(36.7) ꭓ2 =1.516 p = 0.469 Moderate 16(53.4) 17(56.7) Sever 5(16.6) 2(6.6) Cough No/ mild 9(30) 10(33.3) ꭓ2 =0.420 p = 0.810 Moderate 14(46.7) 15(50) Sever 7(23.3) 5(16.7) Dyspnea No/ mild 11(36.7) 13(43.3) ꭓ2 =0.667 p = 0.717 Moderate 14(46.7) 14(46.7) Sever 5(16.6) 3(10) Throat pain No/ mild 16(53.3) 15(50) ꭓ2 =0.175 p = 0.916 Moderate 11(36.7) 11(36.7) Sever 3(10) 4(13.3) Myalgia No/ mild 9(30) 11(36.7) ꭓ2 =0.373 p = 0.830 Moderate 17(56.7) 16(53.3) Sever 4(13.3) 3(10) Fatigue No/ mild 10(33.3) 12(40) ꭓ2 =0.307 p = 0.858 Moderate 17(56.7) 15(50) Sever 3(10) 3(10) GI disorders No/ mild 14(46.7) 19(63.3) ꭓ2 =1.758 p = 0.415 Moderate 14(46.7) 10(33.3) Sever 2(6.6) 1(3.4) Smell disorders No/ mild 13(43.4) 15(50) ꭓ2 =0.810 p = 0.667 Moderate 13(43.4) 13(43.4) Sever 4(13.2) 2(6.6) Tasting disorders No/ mild 15(50) 16(53.4) ꭓ2 =0.366 p = 0.833 Moderate 13(43.3) 13(43.3) Sever 2(6.7) 1(3.3) Visual disorders No/mild 23(67.7) 24(80) ꭓ2 =0.098 p = 0.754 Moderate 7(23.3) 6(20) Table no.2: comparison of laboratory findings in two groups Signs Severity No flu vaccine Flu vaccine group Test result HB normal 21(70.1) 28(93.4) Fisher exact p = 0.042 decrease 8(26.6) 2(6.6) increase 1(3.3) 0 WBC normal 13(43.3) 10(33.3) ꭓ2 =0.648 p = 0.792 decrease 16(53.4) 19(63.4) increase 1(3.3) 1(3.3) PLT normal 7(23.3) 11(36.6) ꭓ2 =1.86 p = 0.438 decrease 22(73.4) 17(56.8) increase 1(3.3) 2(6.6) CRP negative 11(36.7) 12(40) ꭓ2 =0.120 p = 1.0 1+ 12(40) 12(40) 2+ 7(23.3) 6(20) Discussion The results of the present study indicated that the most common initial symptoms for hospitalization in both groups of patients included fever, cough, myalgia, and fatigue. In the study by Jalali Farahani, the most common symptoms were cough, shortness of breath, fever, weakness, myalgia, and chills [ 31 ]. In the study by Jaafarabadi et al., the symptoms of fever, chills, cough, and myalgia were reported in the majority of patients [ 32 ]. Similarly, Huang and Guan in their studies confirmed this finding [ 18 , 33 ]. The comparison of the occurrence and severity of clinical symptoms in the two groups showed that there was no significant difference in the occurrence and severity of clinical symptoms between individuals with and without a history of influenza vaccination. This finding is consistent with the results of the Evidence-Based Medical Consortium of the United States. The Evidence-Based Medical Public Health and Environmental Toxicology Consortium (EBMPHET) (2020) conducted a study titled "Does Seasonal Influenza Vaccination Play a Role in the Severity of COVID-19 in Europe and the United States?" In this study, the vaccination coverage in elderly individuals (65 years and older) and the risk of contracting COVID-19 or the severity of the disease were studied. Data from European and American countries were collected separately. The results showed a positive and significant relationship between influenza vaccination coverage and the occurrence of COVID-19 and its mortality rate in European countries, but no significant relationship was found in American countries [ 34 ]. Additionally, this finding aligns with the study by Kalantari et al., where they showed that there was no significant difference between patients with and without a history of influenza vaccination in terms of average hospital stay, ICU admission rate, and ICU stay duration [ 2 ]. In a meta-analysis and systematic review by Almadhoon et al., it was also shown that there was no significant difference between the two groups with and without influenza vaccination in terms of mortality, clinical symptoms, and hospitalization due to COVID-19 [ 35 ]. Furthermore, these findings are consistent with the study by Malekzadeh et al. They found that influenza vaccination had a lower incidence in individuals infected with COVID-19 compared to non-infected individuals, but this difference was not significant in those vaccinated one year ago. Also, there was no significant correlation between influenza vaccination and the severity of COVID-19 [36]. However, the results of the present study do not align with the study by Arokiaraj et al. (2020). They conducted a study titled "The Relationship between Influenza Vaccination and Its Impact on the Severity of COVID-19 and Other Aspects of the Disease." Their results indicated that influenza vaccination (single-dose) was a determining factor against the severity of COVID-19. Additionally, pneumococcal vaccination (single-dose) reduced the severity of COVID-19 [ 37 ]. Likewise, Lisewski et al. (2020) conducted a study titled "The Relationship between Influenza Vaccination Rates and the Incidence of CoV-SARS-2 Infections in OECD Countries." Their results showed a significant relationship between the influenza vaccination rate in 21 countries and the incidence of CoV-SARS-2 infections. The researchers suggested that influenza vaccination history may be associated with SARS-CoV-2 infection, but further studies were recommended [ 38 ]. Lyu et al. (2020) in China conducted a study titled "The Low Incidence of COVID-19 in Children: Does Vaccination Play a Role in Protection against COVID-19?" In their review, it was found that only 2% of children in China were infected with COVID-19, and most had mild cases. Additionally, their findings indicated that vaccination against tuberculosis, influenza, and pneumonia might impact the incidence and severity of COVID-19 [ 39 ]. The findings of the current study do not match with the findings of Lyu's study. The results of the present study, comparing laboratory findings in COVID-19 patients with and without a history of influenza vaccination, showed no significant differences in CRP, WBC, and PLT levels. However, there was a significant difference in hemoglobin changes between the two groups, with a greater reduction in hemoglobin in the group without a history of influenza vaccination. In Kalantari’s study, CRP and WBC levels showed no significant differences between the two groups. The study did not report platelet and hemoglobin levels [ 2 ]. In a review study by Wanying et al., 16 studies examining the relationship between influenza vaccination and the risk of COVID-19 infection were analyzed. Seven studies examined the relationship between influenza vaccination and the risk of hospitalization in COVID-19 patients, five studies analyzed the relationship between influenza vaccination and the risk of ICU admission in COVID-19 patients, and six studies investigated the relationship between influenza vaccination and the risk of death in COVID-19 patients. This meta-analysis showed that influenza vaccination was associated with a reduced risk of contracting COVID-19 and hospitalization, although it did not show a significant effect on ICU admission and death [ 29 ]. Marín Hernández et al. in their study examined the relationship between influenza vaccination and COVID-19 outcomes in Italy. The results indicated a moderate to strong negative correlation, meaning that in areas with higher influenza vaccination rates, lower COVID-19 mortality was observed. However, they suggested that this result could also be explained by other factors, such as vaccination occurring more often in higher socioeconomic groups, which generally had better health. They also acknowledged that the observed correlation might have been incidental or related to other seasonal respiratory viral infections. Nonetheless, since influenza vaccination is encouraged to reduce hospitalizations and assist in the differential diagnosis of viral respiratory distress in adults, the benefits of influenza vaccination in areas experiencing SARS-CoV-2 infections are well-recognized. Epidemiological and observational studies, as well as further vaccinations, are needed to determine whether the observed relationship between influenza vaccination and reduced COVID-19 mortality is causal [30]. Kristensen et al. in their cohort study showed that influenza vaccination had no effect on the risk of contracting COVID-19 [ 40 ]. Gutierrez-Camacho et al. in a study aimed at evaluating the potential protective effect of the influenza vaccine on the occurrence of symptoms and prognosis in COVID-19 hospitalized patients showed that influenza vaccination was a protective factor against specific COVID-19 symptoms like polyphagia, anosmia, and fever. Additionally, vaccinated patients had shorter hospital stays, but the vaccine did not affect the outcome of COVID-19 disease. Laboratory findings were not examined in their study [ 41 ]. El-Qutob et al. in their study concluded that influenza vaccination had neither a beneficial nor harmful effect on the clinical course or outcomes of hospitalized COVID-19 patients in a European hospital. They found no significant difference in influenza vaccination status among deceased COVID-19 patients. Their results showed no significant difference in CRP, PLT, or lymphocytes between the two groups, but there was a significant difference in hemoglobin levels [42]. Conclusion One of the factors influencing the outcome of COVID-19 is hemoglobin. Hemoglobin levels decrease during COVID-19. This leads to reduced oxygen delivery to tissues, weakening the immune system, and exacerbating the disease. Other studies also showed that decreased hemoglobin levels were significantly more prevalent among COVID-19 patients compared to healthy individuals and were associated with mortality. Therefore, hemoglobin serves as an important indicator for determining the disease course and its complications. The results of the present study demonstrate a relationship between influenza vaccination and changes in hemoglobin levels in COVID-19 patients. Hemoglobin levels are associated with the severity and progression of COVID-19, and a decrease in hemoglobin can exacerbate the disease's outcomes. Previous studies have addressed anemia as an underlying factor contributing to the severity of COVID-19. Therefore, attention to hemoglobin levels and preventing their decrease should be considered. Given the current situation in Iran, where there is no mandatory protocol for COVID-19 vaccination and the general public’s reluctance toward vaccination, and since the acceptance of COVID-19 vaccination remains uncertain, influenza vaccination is recommended. Declarations Acknowledgments: This article is derived from a master's thesis. We would like to thank the Research Vice-Chancellor of Gonabad University of Medical Sciences for their support. The researchers also express their gratitude to all the patients who participated in the study. Funding: There is no funding. Conflicts of interest: There are no conflicts of interest in this article. Ethics approval: IR.GMU.REC.1400.054 Consent to participate: Written informed consent was obtained from all patients. Consent for publication: All authors signed a consent form for publication. Availability of data and material: Not applicable' for that section Code availabilit y: Not applicable' for that section Authors' contributions: Akram sadat hoseini: Ideation, proposal writing, data gathering, article writing Mahdi Basiri Moghaddam: Proposal writing, data analysis, Interpretation of findings, article writing Moosa sajjadi: Data analysis, Interpretation of findings, article writing Mehrsa Basiri Moghaddam: Ideation, proposal writing, data analysis, Interpretation of findings, article writing and editing References Bell J, Meng L, Barbre K, et al. Influenza and COVID-19 Vaccination Coverage Among Health Care Personnel — National Healthcare Safety Network, United States, 2023–24 Respiratory Virus Season. MMWR Morb Mortal Wkly Rep 2024;73:966–972. DOI: http://dx.doi.org/10.15585/mmwr.mm7343a2 Kalantari S, Sadeghzadeh-Bazargan A, Ebrahimi S, Yassin Z, Faiz SHR, Kabir A, Baghestani A, Mashayekhi F, Bokharaei-Salim F, Goodarzi A. The effect of influenza vaccine on severity of COVID-19 infection: An original study from Iran. Med J Islam Repub Iran. 2021 Sep 7;35:114. doi: 10.47176/mjiri.35.114. PMID: 34956960; PMCID: PMC8683836. Yechezkel, M., Qian, G., Levi, Y. et al. Comparison of physiological and clinical reactions to COVID-19 and influenza vaccination. Commun Med 4, 169 (2024). https://doi.org/10.1038/s43856-024-00588-7 Walter EB, Schlaudecker EP, Talaat KR, et al. Safety of Simultaneous vs Sequential mRNA COVID-19 and Inactivated Influenza Vaccines: A Randomized Clinical Trial. JAMA Netw Open. 2024;7(11):e2443166. doi:10.1001/jamanetworkopen.2024.43166 Barouch SE, Chicz TM, Blanc R, Barbati DR, Parker LJ, Tong X, McNamara RP. Concurrent administration of COVID-19 and influenza vaccines enhances Spike-specific antibody responses. bioRxiv [Preprint]. 2023 Sep 12:2023.09.12.557347. doi: 10.1101/2023.09.12.557347. Update in: Open Forum Infect Dis. 2024 Mar 13;11(4):ofae144. doi: 10.1093/ofid/ofae144. PMID: 37745590; PMCID: PMC10515870. Pang J, Wang MX, Ang IYH, Tan SHX, Lewis RF, ChenJIP ChenJIP. et al. Potential Rapid Diagnostics, Vaccine and Therapeutics for 2019 Novel Coronavirus (2019-nCoV): A Systematic Review. J Clin Med. 2020;9(3):623. doi: 10.3390/jcm9030623. Osterholm MT, Kelley NS, Sommer A, Belongia EA. Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis [published correction appears in Lancet Infect Dis 2012 Sep;12(9):655] Lancet Infect Dis. 2012;12(1):36–44. doi: 10.1016/S1473-3099(11)70295-X. Lansburya PE, SmithaSh SmithaSh, Beyer W, Karamehic E, Pasic-Juhas E Pasic-Juhas E, Hana Sikira H. et al. Effectiveness of 2009 pandemic influenza A(H1N1) vaccines: A systematic review and meta-analysis. Vaccine. 2017;35:1996–2006. doi: 10.1016/j.vaccine.2017.02.059. Piri Gharaghie T, Beiranvand S, Doosti A, Ghadiri A H, Haji Mohammadi S. A review of the epidemiology and clinical signs of SARS-COV-2. NCMBJ 2020; 11 (41) :103-120 URL: http://ncmbjpiau.ir/article-1-1343-fa.html ghazanchaei E, Jebelli B, varahram M, Kazempour M, Roozbahani R, ahmadi A. Epidemiology of Hospitalized Patients With COVID-19 in Masih Daneshvari Hospital in Tehran, Iran. JMIS 2023; 9 (3) :210-221.URL: http://jmis.hums.ac.ir/article-1-454-fa.html Wang D, Hu B, Hu C, Zhu F, Liu X, Zhang J, et al. Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in Wuhan, China. JAMA. 2020; 323(11):1061-9. [DOI:10.1001/jama.2020.1585] [PMID] Khotbehsara EM, Askarizad R, Mehrinejad M, Nasab SN, Somasundaraswaran K. The impact of COVID-19 on visitors’ wayfinding within healthcare centers. Ain Shams Eng J. 2023; 14(5):101957. [DOI:10.1016/j.asej.2022.101957] Li T, Lu H, Zhang W. Clinical observation and management of COVID-19 patients. Emerg Microbes Infect. 2020; 9(1):687-90. [DOI:10.1080/22221751.2020.1741327] CDC COVID-19 Response Team. Severe outcomes among patients with coronavirus disease 2019 (COVID-19)-United States, February 12-March 16, 2020. MMWR Morb Mortal Wkly Rep. 2020; 69(12):343-6. [DOI:10.15585/mmwr.mm6912e2] Batubara BM. The problems of the world of education in the middle of the covid-19 pandemic. Budapest Int Res Critics Inst. 2021; 4(1):450-7. [DOI:10.33258/birci.v4i1.1626] Jordan RE, Adab P, Cheng KK. Covid-19: risk factors for severe disease and death. BMJ. 2020 Mar 26;368:m1198. doi: 10.1136/bmj.m1198. PMID: 32217618. Wu Z, McGoogan JM. Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in China: Summary of a report of 72 314 cases from the Chinese Center for Disease Control and Prevention. JAMA. 2020; 323(13):1239-42. [DOI:10.1001/jama.2020.2648] Huang C, Wang Y, Li X, Ren L, Zhao J, Hu Y, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020; 395(10223):497-506. [DOI:10.1016/S0140-6736(20)30183-5] Tsai PH, Lai WY, Lin YY, Luo YH, Lin YT, Chen HK, et al. Clinical manifestation and disease progression in COVID-19 infection. J Chin Med Assoc. 2021; 84(1):3-8. [DOI:10.1097/JCMA.0000000000000463] Mehta OP, Bhandari P, Raut A, Kacimi SEO, Huy NT. Coronavirus disease (COVID-19): Comprehensive review of clinical presentation. Front Public Health. 2021; 8:582932. [DOI:10.3389/fpubh.2020.582932] Mokariani M , Mokariani Z, Amiri F , Ghadamgahi F. Correlation of red blood cell indices with CRP and IL-6 in Covid-19 patients admitted to Hamadan hospitals in 2020, 2021. Sci J Iran Blood Transfus Organ 2024; 21 (2): 160-168 Amiri F, Solgi E , Mohammadi Parsa N, Rafiee Mehr H. Evaluation of blood index changes in Covid-19 inpatients of Hamadan Besat hospital in 2020-2021 . Sci J Iran Blood Transfus Organ 2023;20 (3): 204-213 Ghazanfari T, Salehi MR, Namaki S, Arabkheradmand J, Rostamian A, Rajabnia Chenary M, et al. Interpretation of Hematological, Biochemical, and Immunological Findings of COVID-19 Disease: Biomarkers Associated with Severity and Mortality. Iran J Allergy Asthma Immunol 2021; 20(1): 46-6. Lan Yao, J Carolyn Graff, Weikuan Gu, Dianjun Sun - Influenza vaccination may have only minimum or no effect on COVID-19 in the aged population: BMJ Global Health 2022;7:e010332. Conlon A, Ashur C, Washer L, Eagle KA, Hofmann Bowman MA.Impact of the influenza vaccine on COVID-19 infection rates and severity.American Journal of Infection Control. 2021; 49(6):694-700 Candelli, M., Pignataro, G., Torelli, E. et al. Effect of influenza vaccine on COVID-19 mortality: a retrospective study. Intern Emerg Med 16, 1849–1855 (2021). https://doi.org/10.1007/s11739-021-02702-2 Eldanasory OA, Rabaan AA, Al-Tawfiq JA. Can influenza vaccine modify COVID-19 clinical course? Travel Med Infect Dis. 2020 Sep-Oct;37:101872. doi: 10.1016/j.tmaid.2020.101872. Epub 2020 Sep 5. PMID: 32896672; PMCID: PMC7836515. Salem ML, El-Hennawy D. The possible beneficial adjuvant effect of influenza vaccine to minimize the severity of COVID-19. Med Hypotheses. 2020 Apr 22;140:109752. doi: 10.1016/j.mehy.2020.109752. Epub ahead of print. PMID: 32361099; PMCID: PMC7194943. Wanying Su, Hao Wang, Chenyu Sun, Ning Li, Xianwei Guo, Qiuxia Song, Qiwei Liang, Mingming Liang, Xiuxiu Ding, Yehuan Sun.The Association Between Previous Influenza Vaccination and COVID-19 Infection Risk and Severity: A Systematic Review and Meta-analysis.American Journal of Preventive Medicine.2022;63(1):121-130. Marín-Hernández D, Schwartz RE, Nixon DF. Epidemiological evidence for association between higher influenza vaccine uptake in the elderly and lower COVID-19 deaths in Italy. J Med Virol. 2021 Jan;93(1):64-65. doi: 10.1002/jmv.26120. Epub 2020 Jun 9. PMID: 32497290; PMCID: PMC7300995. Jalali Farahani A, Swann J, Razi S, Mohammadi M, Amani J, Javadzadeh H etal. Comparison of Clinical, Laboratory and Radiological Findings in Iranian Elderly and Non-Elderly Patients with COVID-19. Journal of Marine Medicine;2021;2(4):216-224 Jaafarabadi M, Bagheri M, Shariat M, Raeisie K, Ranjbar A, Ghafoori F, et al. The evaluation of clinical symptoms and underlying factors in infected patients with Covid-19. Tehran University Medical Journal TUMS Publications. 2021;78(10):668-77. Guan WJ, Ni ZY, Hu Y, Liang WH, Ou CQ, He JX, et al. Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med. 2020;382(18):1708-20. Consortium E. COVID-19 Severity in Europe and the USA: Could the seasonal influenza vaccination play a role? Social Science Research Network. 2020 Almadhoon, H.W., Hamdallah, A., Elsayed, S.M. et al. The effect of influenza vaccine in reducing the severity of clinical outcomes in patients with COVID-19: a systematic review and meta-analysis. Sci Rep 12, 14266 (2022). https://doi.org/10.1038/s41598-022-18618-6. Malekzadeh R, Heydari K, Musazadeh M, Asadi T. Incidence and severity of covid-19 among hospital employees of Mazandaran University of Medical Sciences and its relationship with seasonal influenza vaccination in 2019. Magazine of Mazandaran University of Medical Sciences (University Letter).2021; 31(199): 19-12. Arokiaraj MC. Correlation of influenza vaccination and influenza incidence on COVID-19 severity and other perspectives. Available at SSRN 3572814. 2020. Lisewski AM. Association between influenza vaccination rates and SARS-CoV-2 outbreak infection rates in OECD countries. Available at SSRN 3558270. 2020. Lyu J, Miao T, Dong J, Cao R, Li Y, Chen Q. Reflection on lower rates of COVID-19 in children: Does childhood immunizations offer unexpected protection? Medical Hypotheses. 2020; 143:109842. Kristensen JH, Hasselbalch RB, Pries-Heje M, Nielsen PB, Knudsen AD, Fogh K etal. Effect of Influenza Vaccination on Risk of Coronavirus Disease 2019: A Prospective Cohort Study of 46 000 Healthcare Workers. The Journal of Infectious Diseases.2022; 226(1):6-10. https://doi.org/10.1093/infdis/jiac001 Gutierrez-Camacho, J.R.; Avila-Carrasco, L.; Gamón-Madrid, A.; Muñoz-Torres, J.R.; Murillo-Ruiz-Esparza, A.; Garza-Veloz, I.; Trejo-Ortiz, P.M.; Mollinedo-Montaño, F.E.; Araujo-Espino, R.; Rodriguez-Sanchez, I.P.; et al. Evaluation of the Effect of Influenza Vaccine on the Development of Symptoms in SARS-CoV-2 Infection and Outcome in Patients Hospitalized due to COVID-19. Vaccines 2024, 12, 765. https://doi.org/10.3390/ vaccines12070765 El-Qutob D, Nieto M, Alvarez-Arroyo L Carrera-Hueso FJ. Is there any effect of flu vaccine on the SARS-CoV-2 infected patients?. Vacunas.2022;23(2):71-76. Additional Declarations No competing interests reported. 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Sciences","correspondingAuthor":false,"prefix":"","firstName":"Mahdi","middleName":"","lastName":"BasiriMoghaddam","suffix":""},{"id":515986821,"identity":"2547d560-2a10-4845-9a01-66a67899d71e","order_by":2,"name":"Moosa Sajjadi","email":"","orcid":"","institution":"Gonabad University of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Moosa","middleName":"","lastName":"Sajjadi","suffix":""},{"id":515986825,"identity":"bd4a6aa9-ded9-45c4-93b0-631959e03afe","order_by":3,"name":"Mehrsa BasiriMoghaddam","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAz0lEQVRIiWNgGAWjYBACCQYeIGnAwMMPE2EjWotkA2laQLoOEOswyQbegx9/FNyTMT6/Ok2CocaOgU+agGZpBr5kaR6DYh6zG2+3STAcS2Zg40vAr0WOgcdAmsEgAajlLFAL2wEGNh4CDgNqMf75A6jFeAZIyz8itEgz8JhJ8AC1GPD3bpNgbCNCi2QzX5o1SIvEDd7NFol9yTwEtUgc7z1888efBHv+/rMbb3z4Zicn30NACwMzXHMCAwMQEbIDGfAfIEHxKBgFo2AUjCgAALggMxjNnJfdAAAAAElFTkSuQmCC","orcid":"","institution":"Gonabad 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06:26:54","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":622359,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6840424/v1/98d7e9c4-bf0e-4bf0-9594-7dede27f1565.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Hemoglobin changes in Covid-19 patients with and without a history of influenza vaccination","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAlthough the COVID-19 public health emergency has ended, thousands of COVID-19-related hospitalizations and hundreds of COVID-19-related deaths still occur weekly [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. COVID-19 infection is a viral infection that primarily targets the respiratory system [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe unprecedented global impact of COVID-19 led to the rapid development and deployment of vaccines against the virus, including those using new mRNA technology [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Walter states that the ultimate goal is to provide high levels of vaccination coverage during the anticipated periods of influenza and COVID-19 virus transmission, protecting those at higher risk. The influenza vaccine is administered annually to high-risk individuals. Additionally, vaccines were developed in response to the COVID-19 pandemic, which became available for the first time in December 2020 [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. However, the widespread availability of COVID-19 vaccines occurred in the fall of 2022, when they were recommended alongside the seasonal influenza vaccine. The introduction of the bivalent mRNA COVID-19 vaccines coincided with the seasonal influenza vaccines in the fall of 2022 [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eDespite the promising safety profiles and efficacy of mRNA vaccines in preventing severe COVID-19 outcomes, there has been significant public reluctance to get vaccinated globally. For example, in the United States, nearly 20% of the population has not received any dose of the COVID-19 vaccine. By May 4, 2024, 27.7% of the population in Israel had not received any COVID-19 vaccine. Among seniors aged 65 and older, vaccination coverage for the first and second COVID-19 booster shots was 82.6% and 47.8%, respectively. National influenza vaccine coverage was 15.3%, while 52.3\u0026ndash;58.6% of the elderly population was vaccinated against influenza. One of the main reasons for COVID-19 vaccine hesitancy is safety concerns regarding the vaccine [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Furthermore, from a managerial perspective, there is still no standardized protocol for COVID-19 vaccination [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. One of the pandemic management strategies focuses on the protective, therapeutic, and immune-boosting potentials [\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAnother reality that must be addressed is that COVID-19 vaccines need modification and updates to adapt to viral mutations for protection against COVID-19 infection [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Studies have shown that the number of COVID-19 vaccinations in each season continues to decline [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eRespiratory viruses, including the coronavirus, pose a serious threat to global health security and can lead to high mortality and significant financial burdens for treatment [9]. The global spread of this disease has been a stark reminder that infectious diseases remain a persistent threat to human health, especially emerging and re-emerging diseases, which always pose a potential challenge to healthcare systems worldwide (10\u0026ndash;13). COVID-19 infection can lead to severe outcomes, including death or admission to intensive care units (ICUs) [\u003cspan additionalcitationids=\"CR15\" citationid=\"CR13\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. However, the full clinical characteristics and outcomes of this disease are still not entirely known. Nevertheless, early studies conducted in China described a wide spectrum of the disease, from mild to severe, based on the patients\u0026rsquo; age, underlying conditions, and mortality [17\u0026ndash;20].\u003c/p\u003e\u003cp\u003eSince the global impact of this virus continues and the mutations in the virus cause additional problems, it is crucial to focus on alleviating and reducing symptoms of the disease and minimizing the associated burden and mortality. In other words, post-pandemic studies are necessary to identify effective strategies for symptom reduction, speeding up treatment and recovery, and reducing disease-related complications. It seems that existing vaccines for other respiratory viruses might be helpful in reducing the severity of COVID-19 [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. As influenza, COVID-19, and other respiratory viruses typically peak in the winter months, individuals usually receive influenza and COVID-19 vaccines in late summer or early fall if they wish [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In Iran, influenza vaccination is provided to high-risk individuals or optionally to anyone who desires it, while COVID-19 vaccination is neither mandatory nor routine.\u003c/p\u003e\u003cp\u003eSeveral studies have investigated the effects of influenza vaccination on various aspects of COVID-19, including outcomes, mortality, and hospitalization rates [21\u0026ndash;30, 1\u0026ndash;5], yielding varying results. Therefore, further evaluation seemed necessary. This study aimed to compare the clinical and laboratory findings in COVID-19 patients with and without a history of influenza vaccination.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy design\u003c/h2\u003e\u003cp\u003eThe present study is a comparative analytical study involving two groups. Sixty COVID-19 patients (30 per group) were compared in terms of hemoglobin changes, clinical symptoms, and laboratory findings between two groups with and without a history of influenza vaccination. Patients selected from Ferdows and Gonabad bohlool hospitals.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eSetting\u003c/h3\u003e\n\u003cp\u003eThe study population included hospitalized patients from Ferdows and Gonabad bohlool hospitals in 2023\u0026ndash;2024 who were diagnosed with COVID-19 based on a positive PCR test.\u003c/p\u003e\n\u003ch3\u003eParticipants\u003c/h3\u003e\n\u003cp\u003eSampling was performed using a convenience sampling method based on inclusion criteria. Inclusion Criteria: Patients who visited Ferdows and Gonabad hospitals with a positive PCR test for COVID-19 and who were willing to participate in the study.\u003c/p\u003e\n\u003ch3\u003eData sources/ measurement\u003c/h3\u003e\n\u003cp\u003eData were collected using a questionnaire with five sections: A)Demographic Information Form: including age, gender, marital status, occupation, education level. B) Risk Factors Form: including a history of cardiovascular, kidney, liver diseases, diabetes, hypertension, and lung diseases such as asthma. This form was filled out based on self-reporting by the patient. C) Clinical Symptoms Form: including fever, cough, shortness of breath, sore throat, muscle pain, fatigue, gastrointestinal disorders (diarrhea and vomiting), loss of smell, loss of taste, and vision disturbances (eye redness and tearing). D) Laboratory Symptoms Form: including CRP and CBC test results. E) Influenza Vaccination History: based on self-reporting, yes or no, and if yes, the date of vaccination.\u003c/p\u003e\n\u003ch3\u003eStudy size\u003c/h3\u003e\n\u003cp\u003eThe sample size was determined using G*Power version 3.1.9.2 with an effect size of 1.03, resulting in 22 participants per group and a total of 44 participants. To account for potential sample attrition, this number was increased to 30 participants per group. It should be noted that the effect size was derived from a pilot study, specifically for the hemoglobin variable, based on the mean and standard deviation of hemoglobin in the vaccinated group (14.8\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2) and the unvaccinated group (13.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.12).\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eQuantitative variables\u003c/h2\u003e\u003cp\u003eAfter obtaining ethical approval from the Medical University of Gonabad and presenting it to the relevant authorities at Ferdows and Gonabad hospitals, patients diagnosed with COVID-19 (positive PCR test) who met the inclusion criteria were included in the study using a convenience sampling method. For all hospitalized patients, demographic information, risk factors, and clinical symptoms forms were completed based on self-reporting by the patients, observations, and, in some cases, based on medical records. For discharged patients, the medical records were reviewed, and the relevant questionnaire was completed based on the information available and, if necessary, through a personal interview with the patient. The influenza vaccination history was recorded based on self-reporting, with the date of vaccination, if applicable. Ethical considerations in this study included obtaining informed consent from all participants, ensuring no physical or psychological harm from the intervention, commitment to reporting the results to the university, following the ethical guidelines of Gonabad University of Medical Sciences, and maintaining the confidentiality of all information.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eStatistical methods\u003c/h3\u003e\n\u003cp\u003eData were analyzed using SPSS version 18. Descriptive statistics (frequency distribution tables, mean, and standard deviation) and inferential statistics (independent t-test and Chi-square test) were used. The Shapiro-Wilk test was used to determine the normality of quantitative variables. The significance level for all statistical tests was set at 0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe average age of the study participants was 48.81\u0026thinsp;\u0026plusmn;\u0026thinsp;21.58 years. Of the 60 participants, 31 were male (51.6%), 27 (45%) had education below high school, 36 (60%) were married, 41 (68.3%) lived in urban areas, 18 (30%) had a freelance job, and 31 (51.6%) had no underlying diseases. The most common underlying disease among the participants was cardiovascular disease (37.4%). Seventy-one percent reported not smoking, and 93.3% reported not drinking alcohol. Thirty-eight percent had blood type B. According to the Chi-square test, no significant differences were found between the two groups regarding these variables (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05).The study results showed that the most common clinical symptoms in these patients were fever, cough, myalgia, weakness, and fatigue. The comparison of frequency of clinical symptoms including fever, cough, shortness of breath, sore throat, myalgia, weakness, fatigue, gastrointestinal symptoms, and sensory impairments (smell, taste, and vision) using the chi square test showed that in the influenza-vaccinated group, the symptoms were less severe, and fewer individuals experienced severe symptoms, although this difference was not statistically significant (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Table\u0026nbsp;1).\u003c/p\u003e\u003cp\u003eThe comparison of laboratory symptoms indicated no significant differences between the two groups in CRP, WBC, and Platelet levels. However, the comparison of hemoglobin levels between the two groups revealed a significant difference, with a more pronounced decrease in hemoglobin in the group without a history of influenza vaccination (P\u0026thinsp;=\u0026thinsp;0.042) (Table\u0026nbsp;2).\u003c/p\u003e\u003cp\u003eTable no.1: comparison of clinical signs in two groups\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e\u003ccolgroup cols=\"5\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSigns\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSeverity\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNo flu vaccine\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFlu vaccine group\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eTest result\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eFever\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo/ mild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9(30)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e11(36.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=1.516\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.469\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16(53.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e17(56.7)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSever\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5(16.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2(6.6)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eCough\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo/ mild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9(30)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e10(33.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=0.420\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.810\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14(46.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e15(50)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSever\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7(23.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5(16.7)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eDyspnea\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo/ mild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11(36.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e13(43.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=0.667\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.717\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14(46.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e14(46.7)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSever\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5(16.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3(10)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eThroat pain\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo/ mild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16(53.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e15(50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=0.175\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.916\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11(36.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e11(36.7)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSever\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3(10)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4(13.3)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eMyalgia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo/ mild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9(30)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e11(36.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=0.373\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.830\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e17(56.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e16(53.3)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSever\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4(13.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3(10)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eFatigue\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo/ mild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10(33.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cspan type=\"ItalicUnderline\" class=\"ItalicUnderline\" name=\"Emphasis\"\u003e12(40)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=0.307\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.858\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e17(56.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e15(50)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSever\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3(10)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3(10)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eGI disorders\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo/ mild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14(46.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e19(63.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=1.758\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.415\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14(46.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e10(33.3)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSever\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2(6.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1(3.4)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eSmell disorders\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo/ mild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13(43.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e15(50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=0.810\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.667\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13(43.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e13(43.4)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSever\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4(13.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2(6.6)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eTasting disorders\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo/ mild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15(50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e16(53.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=0.366\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.833\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13(43.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e13(43.3)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSever\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2(6.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1(3.3)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eVisual disorders\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo/mild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e23(67.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e24(80)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=0.098\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.754\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7(23.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6(20)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eTable no.2: comparison of laboratory findings in two groups\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e\u003ccolgroup cols=\"5\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSigns\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSeverity\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNo flu vaccine\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFlu vaccine group\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eTest result\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eHB\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003enormal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e21(70.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e28(93.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eFisher exact p\u0026thinsp;=\u0026thinsp;0.042\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003edecrease\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8(26.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2(6.6)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eincrease\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1(3.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eWBC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003enormal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13(43.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e10(33.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=0.648\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.792\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003edecrease\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16(53.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e19(63.4)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eincrease\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1(3.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1(3.3)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003ePLT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003enormal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7(23.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e11(36.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=1.86\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.438\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003edecrease\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e22(73.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e17(56.8)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eincrease\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1(3.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2(6.6)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eCRP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003enegative\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11(36.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e12(40)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eꭓ2\u0026nbsp;=0.120\u003c/p\u003e\u003cp\u003ep\u0026thinsp;=\u0026thinsp;1.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12(40)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e12(40)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7(23.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6(20)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe results of the present study indicated that the most common initial symptoms for hospitalization in both groups of patients included fever, cough, myalgia, and fatigue. In the study by Jalali Farahani, the most common symptoms were cough, shortness of breath, fever, weakness, myalgia, and chills [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. In the study by Jaafarabadi et al., the symptoms of fever, chills, cough, and myalgia were reported in the majority of patients [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Similarly, Huang and Guan in their studies confirmed this finding [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe comparison of the occurrence and severity of clinical symptoms in the two groups showed that there was no significant difference in the occurrence and severity of clinical symptoms between individuals with and without a history of influenza vaccination. This finding is consistent with the results of the Evidence-Based Medical Consortium of the United States. The Evidence-Based Medical Public Health and Environmental Toxicology Consortium (EBMPHET) (2020) conducted a study titled \"Does Seasonal Influenza Vaccination Play a Role in the Severity of COVID-19 in Europe and the United States?\" In this study, the vaccination coverage in elderly individuals (65 years and older) and the risk of contracting COVID-19 or the severity of the disease were studied. Data from European and American countries were collected separately. The results showed a positive and significant relationship between influenza vaccination coverage and the occurrence of COVID-19 and its mortality rate in European countries, but no significant relationship was found in American countries [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. Additionally, this finding aligns with the study by Kalantari et al., where they showed that there was no significant difference between patients with and without a history of influenza vaccination in terms of average hospital stay, ICU admission rate, and ICU stay duration [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. In a meta-analysis and systematic review by Almadhoon et al., it was also shown that there was no significant difference between the two groups with and without influenza vaccination in terms of mortality, clinical symptoms, and hospitalization due to COVID-19 [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Furthermore, these findings are consistent with the study by Malekzadeh et al. They found that influenza vaccination had a lower incidence in individuals infected with COVID-19 compared to non-infected individuals, but this difference was not significant in those vaccinated one year ago. Also, there was no significant correlation between influenza vaccination and the severity of COVID-19 [36].\u003c/p\u003e\u003cp\u003eHowever, the results of the present study do not align with the study by Arokiaraj et al. (2020). They conducted a study titled \"The Relationship between Influenza Vaccination and Its Impact on the Severity of COVID-19 and Other Aspects of the Disease.\" Their results indicated that influenza vaccination (single-dose) was a determining factor against the severity of COVID-19. Additionally, pneumococcal vaccination (single-dose) reduced the severity of COVID-19 [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Likewise, Lisewski et al. (2020) conducted a study titled \"The Relationship between Influenza Vaccination Rates and the Incidence of CoV-SARS-2 Infections in OECD Countries.\" Their results showed a significant relationship between the influenza vaccination rate in 21 countries and the incidence of CoV-SARS-2 infections. The researchers suggested that influenza vaccination history may be associated with SARS-CoV-2 infection, but further studies were recommended [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. Lyu et al. (2020) in China conducted a study titled \"The Low Incidence of COVID-19 in Children: Does Vaccination Play a Role in Protection against COVID-19?\" In their review, it was found that only 2% of children in China were infected with COVID-19, and most had mild cases. Additionally, their findings indicated that vaccination against tuberculosis, influenza, and pneumonia might impact the incidence and severity of COVID-19 [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. The findings of the current study do not match with the findings of Lyu's study.\u003c/p\u003e\u003cp\u003eThe results of the present study, comparing laboratory findings in COVID-19 patients with and without a history of influenza vaccination, showed no significant differences in CRP, WBC, and PLT levels. However, there was a significant difference in hemoglobin changes between the two groups, with a greater reduction in hemoglobin in the group without a history of influenza vaccination. In Kalantari\u0026rsquo;s study, CRP and WBC levels showed no significant differences between the two groups. The study did not report platelet and hemoglobin levels [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn a review study by Wanying et al., 16 studies examining the relationship between influenza vaccination and the risk of COVID-19 infection were analyzed. Seven studies examined the relationship between influenza vaccination and the risk of hospitalization in COVID-19 patients, five studies analyzed the relationship between influenza vaccination and the risk of ICU admission in COVID-19 patients, and six studies investigated the relationship between influenza vaccination and the risk of death in COVID-19 patients. This meta-analysis showed that influenza vaccination was associated with a reduced risk of contracting COVID-19 and hospitalization, although it did not show a significant effect on ICU admission and death [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eMar\u0026iacute;n Hern\u0026aacute;ndez et al. in their study examined the relationship between influenza vaccination and COVID-19 outcomes in Italy. The results indicated a moderate to strong negative correlation, meaning that in areas with higher influenza vaccination rates, lower COVID-19 mortality was observed. However, they suggested that this result could also be explained by other factors, such as vaccination occurring more often in higher socioeconomic groups, which generally had better health. They also acknowledged that the observed correlation might have been incidental or related to other seasonal respiratory viral infections. Nonetheless, since influenza vaccination is encouraged to reduce hospitalizations and assist in the differential diagnosis of viral respiratory distress in adults, the benefits of influenza vaccination in areas experiencing SARS-CoV-2 infections are well-recognized. Epidemiological and observational studies, as well as further vaccinations, are needed to determine whether the observed relationship between influenza vaccination and reduced COVID-19 mortality is causal [30]. Kristensen et al. in their cohort study showed that influenza vaccination had no effect on the risk of contracting COVID-19 [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e40\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eGutierrez-Camacho et al. in a study aimed at evaluating the potential protective effect of the influenza vaccine on the occurrence of symptoms and prognosis in COVID-19 hospitalized patients showed that influenza vaccination was a protective factor against specific COVID-19 symptoms like polyphagia, anosmia, and fever. Additionally, vaccinated patients had shorter hospital stays, but the vaccine did not affect the outcome of COVID-19 disease. Laboratory findings were not examined in their study [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. El-Qutob et al. in their study concluded that influenza vaccination had neither a beneficial nor harmful effect on the clinical course or outcomes of hospitalized COVID-19 patients in a European hospital. They found no significant difference in influenza vaccination status among deceased COVID-19 patients. Their results showed no significant difference in CRP, PLT, or lymphocytes between the two groups, but there was a significant difference in hemoglobin levels [42].\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eOne of the factors influencing the outcome of COVID-19 is hemoglobin. Hemoglobin levels decrease during COVID-19. This leads to reduced oxygen delivery to tissues, weakening the immune system, and exacerbating the disease. Other studies also showed that decreased hemoglobin levels were significantly more prevalent among COVID-19 patients compared to healthy individuals and were associated with mortality. Therefore, hemoglobin serves as an important indicator for determining the disease course and its complications. The results of the present study demonstrate a relationship between influenza vaccination and changes in hemoglobin levels in COVID-19 patients. Hemoglobin levels are associated with the severity and progression of COVID-19, and a decrease in hemoglobin can exacerbate the disease's outcomes. Previous studies have addressed anemia as an underlying factor contributing to the severity of COVID-19. Therefore, attention to hemoglobin levels and preventing their decrease should be considered. Given the current situation in Iran, where there is no mandatory protocol for COVID-19 vaccination and the general public\u0026rsquo;s reluctance toward vaccination, and since the acceptance of COVID-19 vaccination remains uncertain, influenza vaccination is recommended.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis article is derived from a master\u0026apos;s thesis. We would like to thank the Research Vice-Chancellor of Gonabad University of Medical Sciences for their support. The researchers also express their gratitude to all the patients who participated in the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e There is no funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of interest:\u003c/strong\u003e There are no conflicts of interest in this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval:\u003c/strong\u003e\u0026nbsp; IR.GMU.REC.1400.054\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to participate:\u003c/strong\u003e Written informed consent was obtained from all patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication:\u0026nbsp;\u003c/strong\u003eAll authors signed a consent form for publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material:\u0026nbsp;\u003c/strong\u003eNot applicable\u0026apos; for that section\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCode availabilit\u003c/strong\u003ey: Not applicable\u0026apos; for that section\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAkram sadat hoseini: Ideation, proposal writing, data gathering, article writing\u003c/p\u003e\n\u003cp\u003eMahdi Basiri Moghaddam: Proposal writing, data analysis, Interpretation of findings, article writing\u003c/p\u003e\n\u003cp\u003eMoosa sajjadi: Data analysis, Interpretation of findings, article writing\u003c/p\u003e\n\u003cp\u003eMehrsa Basiri Moghaddam: Ideation, proposal writing, data analysis, Interpretation of findings, article writing and editing\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBell J, Meng L, Barbre K, et al. Influenza and COVID-19 Vaccination Coverage Among Health Care Personnel \u0026mdash; National Healthcare Safety Network, United States, 2023\u0026ndash;24 Respiratory Virus Season. MMWR Morb Mortal Wkly Rep 2024;73:966\u0026ndash;972. DOI: http://dx.doi.org/10.15585/mmwr.mm7343a2\u003c/li\u003e\n\u003cli\u003eKalantari S, Sadeghzadeh-Bazargan A, Ebrahimi S, Yassin Z, Faiz SHR, Kabir A, Baghestani A, Mashayekhi F, Bokharaei-Salim F, Goodarzi A. The effect of influenza vaccine on severity of COVID-19 infection: An original study from Iran. Med J Islam Repub Iran. 2021 Sep 7;35:114. doi: 10.47176/mjiri.35.114. PMID: 34956960; PMCID: PMC8683836.\u003c/li\u003e\n\u003cli\u003eYechezkel, M., Qian, G., Levi, Y. et al. Comparison of physiological and clinical reactions to COVID-19 and influenza vaccination. Commun Med 4, 169 (2024). https://doi.org/10.1038/s43856-024-00588-7\u003c/li\u003e\n\u003cli\u003eWalter EB, Schlaudecker EP, Talaat KR, et al. Safety of Simultaneous vs Sequential mRNA COVID-19 and Inactivated Influenza Vaccines: A Randomized Clinical Trial. \u003cem\u003eJAMA Netw Open.\u003c/em\u003e 2024;7(11):e2443166. doi:10.1001/jamanetworkopen.2024.43166\u003c/li\u003e\n\u003cli\u003eBarouch SE, Chicz TM, Blanc R, Barbati DR, Parker LJ, Tong X, McNamara RP. Concurrent administration of COVID-19 and influenza vaccines enhances Spike-specific antibody responses. bioRxiv [Preprint]. 2023 Sep 12:2023.09.12.557347. doi: 10.1101/2023.09.12.557347. Update in: Open Forum Infect Dis. 2024 Mar 13;11(4):ofae144. doi: 10.1093/ofid/ofae144. PMID: 37745590; PMCID: PMC10515870.\u003c/li\u003e\n\u003cli\u003ePang J, Wang MX, Ang IYH, Tan SHX, Lewis RF, ChenJIP ChenJIP. et al. Potential Rapid Diagnostics, Vaccine and Therapeutics for 2019 Novel Coronavirus (2019-nCoV): A Systematic Review. J Clin Med. 2020;9(3):623. doi: 10.3390/jcm9030623. \u003c/li\u003e\n\u003cli\u003eOsterholm MT, Kelley NS, Sommer A, Belongia EA. Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis [published correction appears in Lancet Infect Dis 2012 Sep;12(9):655] Lancet Infect Dis. 2012;12(1):36\u0026ndash;44. doi: 10.1016/S1473-3099(11)70295-X. \u003c/li\u003e\n\u003cli\u003eLansburya PE, SmithaSh SmithaSh, Beyer W, Karamehic E, Pasic-Juhas E Pasic-Juhas E, Hana Sikira H. et al. Effectiveness of 2009 pandemic influenza A(H1N1) vaccines: A systematic review and meta-analysis. Vaccine. 2017;35:1996\u0026ndash;2006. doi: 10.1016/j.vaccine.2017.02.059.\u003c/li\u003e\n\u003cli\u003ePiri Gharaghie T, Beiranvand S, Doosti A, Ghadiri A H, Haji Mohammadi S. A review of the epidemiology and clinical signs of SARS-COV-2. NCMBJ 2020; 11 (41) :103-120 URL: http://ncmbjpiau.ir/article-1-1343-fa.html\u003c/li\u003e\n\u003cli\u003eghazanchaei E, Jebelli B, varahram M, Kazempour M, Roozbahani R, ahmadi A. Epidemiology of Hospitalized Patients With COVID-19 in Masih Daneshvari Hospital in Tehran, Iran. JMIS 2023; 9 (3) :210-221.URL: http://jmis.hums.ac.ir/article-1-454-fa.html\u003c/li\u003e\n\u003cli\u003eWang D, Hu B, Hu C, Zhu F, Liu X, Zhang J, et al. Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in Wuhan, China. JAMA. 2020; 323(11):1061-9. [DOI:10.1001/jama.2020.1585] [PMID] \u003c/li\u003e\n\u003cli\u003eKhotbehsara EM, Askarizad R, Mehrinejad M, Nasab SN, Somasundaraswaran K. The impact of COVID-19 on visitors\u0026rsquo; wayfinding within healthcare centers. Ain Shams Eng J. 2023; 14(5):101957. [DOI:10.1016/j.asej.2022.101957] \u003c/li\u003e\n\u003cli\u003eLi T, Lu H, Zhang W. Clinical observation and management of COVID-19 patients. Emerg Microbes Infect. 2020; 9(1):687-90. [DOI:10.1080/22221751.2020.1741327] \u003c/li\u003e\n\u003cli\u003eCDC COVID-19 Response Team. Severe outcomes among patients with coronavirus disease 2019 (COVID-19)-United States, February 12-March 16, 2020. MMWR Morb Mortal Wkly Rep. 2020; 69(12):343-6. [DOI:10.15585/mmwr.mm6912e2] \u003c/li\u003e\n\u003cli\u003eBatubara BM. The problems of the world of education in the middle of the covid-19 pandemic. Budapest Int Res Critics Inst. 2021; 4(1):450-7. [DOI:10.33258/birci.v4i1.1626]\u003c/li\u003e\n\u003cli\u003eJordan RE, Adab P, Cheng KK. Covid-19: risk factors for severe disease and death. BMJ. 2020 Mar 26;368:m1198. doi: 10.1136/bmj.m1198. PMID: 32217618.\u003c/li\u003e\n\u003cli\u003eWu Z, McGoogan JM. Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in China: Summary of a report of 72 314 cases from the Chinese Center for Disease Control and Prevention. JAMA. 2020; 323(13):1239-42. [DOI:10.1001/jama.2020.2648] \u003c/li\u003e\n\u003cli\u003eHuang C, Wang Y, Li X, Ren L, Zhao J, Hu Y, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020; 395(10223):497-506. [DOI:10.1016/S0140-6736(20)30183-5] \u003c/li\u003e\n\u003cli\u003eTsai PH, Lai WY, Lin YY, Luo YH, Lin YT, Chen HK, et al. Clinical manifestation and disease progression in COVID-19 infection. J Chin Med Assoc. 2021; 84(1):3-8. [DOI:10.1097/JCMA.0000000000000463] \u003c/li\u003e\n\u003cli\u003eMehta OP, Bhandari P, Raut A, Kacimi SEO, Huy NT. Coronavirus disease (COVID-19): Comprehensive review of clinical presentation. Front Public Health. 2021; 8:582932. [DOI:10.3389/fpubh.2020.582932] \u003c/li\u003e\n\u003cli\u003eMokariani M , Mokariani Z, Amiri F , Ghadamgahi F. Correlation of red blood cell indices with CRP and IL-6 in Covid-19 patients admitted to Hamadan hospitals in 2020, 2021. Sci J Iran Blood Transfus Organ 2024; 21 (2): 160-168\u003c/li\u003e\n\u003cli\u003eAmiri F, Solgi E , Mohammadi Parsa N, Rafiee Mehr H. Evaluation of blood index changes in Covid-19 inpatients of Hamadan Besat hospital in 2020-2021 . Sci J Iran Blood Transfus Organ 2023;20 (3): 204-213\u003c/li\u003e\n\u003cli\u003eGhazanfari T, Salehi MR, Namaki S, Arabkheradmand J, Rostamian A, Rajabnia Chenary M, et al. Interpretation of Hematological, Biochemical, and Immunological Findings of COVID-19 Disease: Biomarkers Associated with Severity and Mortality. Iran J Allergy Asthma Immunol 2021; 20(1): 46-6.\u003c/li\u003e\n\u003cli\u003eLan Yao, J Carolyn Graff, Weikuan Gu, Dianjun Sun - Influenza vaccination may have only minimum or no effect on COVID-19 in the aged population: BMJ Global Health 2022;7:e010332.\u003c/li\u003e\n\u003cli\u003eConlon A, Ashur C, Washer L, Eagle KA, Hofmann Bowman MA.Impact of the influenza vaccine on COVID-19 infection rates and severity.American Journal of Infection Control. 2021; 49(6):694-700\u003c/li\u003e\n\u003cli\u003eCandelli, M., Pignataro, G., Torelli, E. et al. Effect of influenza vaccine on COVID-19 mortality: a retrospective study. Intern Emerg Med 16, 1849\u0026ndash;1855 (2021). https://doi.org/10.1007/s11739-021-02702-2\u003c/li\u003e\n\u003cli\u003eEldanasory OA, Rabaan AA, Al-Tawfiq JA. Can influenza vaccine modify COVID-19 clinical course? Travel Med Infect Dis. 2020 Sep-Oct;37:101872. doi: 10.1016/j.tmaid.2020.101872. Epub 2020 Sep 5. PMID: 32896672; PMCID: PMC7836515.\u003c/li\u003e\n\u003cli\u003eSalem ML, El-Hennawy D. The possible beneficial adjuvant effect of influenza vaccine to minimize the severity of COVID-19. Med Hypotheses. 2020 Apr 22;140:109752. doi: 10.1016/j.mehy.2020.109752. Epub ahead of print. PMID: 32361099; PMCID: PMC7194943.\u003c/li\u003e\n\u003cli\u003eWanying Su, Hao Wang, Chenyu Sun, Ning Li, Xianwei Guo, Qiuxia Song, Qiwei Liang, Mingming Liang, Xiuxiu Ding, Yehuan Sun.The Association Between Previous Influenza Vaccination and COVID-19 Infection Risk and Severity: A Systematic Review and Meta-analysis.American Journal of Preventive Medicine.2022;63(1):121-130.\u003c/li\u003e\n\u003cli\u003eMar\u0026iacute;n-Hern\u0026aacute;ndez D, Schwartz RE, Nixon DF. Epidemiological evidence for association between higher influenza vaccine uptake in the elderly and lower COVID-19 deaths in Italy. J Med Virol. 2021 Jan;93(1):64-65. doi: 10.1002/jmv.26120. Epub 2020 Jun 9. PMID: 32497290; PMCID: PMC7300995.\u003c/li\u003e\n\u003cli\u003eJalali Farahani A, Swann J, Razi S, Mohammadi M, Amani J, Javadzadeh H etal. Comparison of Clinical, Laboratory and Radiological Findings in Iranian Elderly and Non-Elderly Patients with COVID-19. Journal of Marine Medicine;2021;2(4):216-224\u003c/li\u003e\n\u003cli\u003eJaafarabadi M, Bagheri M, Shariat M, Raeisie K, Ranjbar A, Ghafoori F, et al. The evaluation of clinical symptoms and underlying factors in infected patients with Covid-19. Tehran University Medical Journal TUMS Publications. 2021;78(10):668-77.\u003c/li\u003e\n\u003cli\u003eGuan WJ, Ni ZY, Hu Y, Liang WH, Ou CQ, He JX, et al. Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med. 2020;382(18):1708-20.\u003c/li\u003e\n\u003cli\u003eConsortium E. COVID-19 Severity in Europe and the USA: Could the seasonal influenza vaccination play a role? Social Science Research Network. 2020\u003c/li\u003e\n\u003cli\u003eAlmadhoon, H.W., Hamdallah, A., Elsayed, S.M. et al. The effect of influenza vaccine in reducing the severity of clinical outcomes in patients with COVID-19: a systematic review and meta-analysis. Sci Rep 12, 14266 (2022). https://doi.org/10.1038/s41598-022-18618-6.\u003c/li\u003e\n\u003cli\u003eMalekzadeh R, Heydari K, Musazadeh M, Asadi T. Incidence and severity of covid-19 among hospital employees of Mazandaran University of Medical Sciences and its relationship with seasonal influenza vaccination in 2019. Magazine of Mazandaran University of Medical Sciences (University Letter).2021; 31(199): 19-12.\u003c/li\u003e\n\u003cli\u003eArokiaraj MC. Correlation of influenza vaccination and influenza incidence on COVID-19 severity and other perspectives. Available at SSRN 3572814. 2020.\u003c/li\u003e\n\u003cli\u003eLisewski AM. Association between influenza vaccination rates and SARS-CoV-2 outbreak infection rates in OECD countries. Available at SSRN 3558270. 2020.\u003c/li\u003e\n\u003cli\u003eLyu J, Miao T, Dong J, Cao R, Li Y, Chen Q. Reflection on lower rates of COVID-19 in children: Does childhood immunizations offer unexpected protection? Medical Hypotheses. 2020; 143:109842.\u003c/li\u003e\n\u003cli\u003eKristensen JH, Hasselbalch RB, Pries-Heje M, Nielsen PB, Knudsen AD, Fogh K etal. Effect of Influenza Vaccination on Risk of Coronavirus Disease 2019: A Prospective Cohort Study of 46 000 Healthcare Workers. The Journal of Infectious Diseases.2022; 226(1):6-10. https://doi.org/10.1093/infdis/jiac001\u003c/li\u003e\n\u003cli\u003eGutierrez-Camacho, J.R.; Avila-Carrasco, L.; Gam\u0026oacute;n-Madrid, A.; Mu\u0026ntilde;oz-Torres, J.R.; Murillo-Ruiz-Esparza, A.; Garza-Veloz, I.; Trejo-Ortiz, P.M.; Mollinedo-Monta\u0026ntilde;o, F.E.; Araujo-Espino, R.; Rodriguez-Sanchez, I.P.; et al. Evaluation of the Effect of Influenza Vaccine on the Development of Symptoms in SARS-CoV-2 Infection and Outcome in Patients Hospitalized due to COVID-19. Vaccines 2024, 12, 765. https://doi.org/10.3390/ vaccines12070765\u003c/li\u003e\n\u003cli\u003eEl-Qutob D, Nieto M, Alvarez-Arroyo L Carrera-Hueso FJ. Is there any effect of flu vaccine on the SARS-CoV-2 infected patients?. Vacunas.2022;23(2):71-76.\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":"COVID-19, SARS-CoV-2, Influenza Vaccination, Hemoglobin, Clinical Symptoms, Laboratory Symptoms","lastPublishedDoi":"10.21203/rs.3.rs-6840424/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6840424/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground:\u003c/h2\u003e\u003cp\u003eAlthough the COVID-19 pandemic has subsided, its significance remains due to its 2\u0026ndash;14 day incubation period, symptom similarity with the common cold, and high transmission ability, as well as its consequences and complications. This study aimed to compare the clinical and laboratory findings in COVID-19 patients with and without a history of influenza vaccination.\u003c/p\u003e\u003ch2\u003eMethods:\u003c/h2\u003e\u003cp\u003eThis study was a comparative analytical study. A total of 60 hospitalized patients from Ferdows Hospital and Behlool Gonabad Hospital were selected based on inclusion criteria and a convenience sampling method. Data collection involved demographic information, clinical symptom forms, and laboratory test results. Data analysis was performed using SPSS version 18.\u003c/p\u003e\u003ch2\u003eResults:\u003c/h2\u003e\u003cp\u003eFindings showed that COVID-19 patients with a history of influenza vaccination had less severe clinical symptoms, with fewer individuals experiencing severe symptoms. However, this difference was not statistically significant. A statistically significant difference (P\u0026thinsp;=\u0026thinsp;.020) was found between the two groups regarding hemoglobin changes, with a greater decrease in hemoglobin levels observed in the unvaccinated group. Comparison of CRP, WBC, and platelet counts between the two groups revealed no statistically significant differences (P\u0026thinsp;\u0026gt;\u0026thinsp;.05).\u003c/p\u003e\u003ch2\u003eConclusions:\u003c/h2\u003e\u003cp\u003eThe results of this study suggest that a history of influenza vaccination influences changes in hemoglobin levels in COVID-19 patients. Given that COVID-19 vaccination is not universally accepted and there is no mandatory vaccination policy, and considering the established impact of reduced hemoglobin levels on the severity and outcomes of COVID-19, influenza vaccination is recommended to prevent complications.\u003c/p\u003e","manuscriptTitle":"Hemoglobin changes in Covid-19 patients with and without a history of influenza vaccination","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-24 23:05:46","doi":"10.21203/rs.3.rs-6840424/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":"c2938176-ee5c-4b23-aba4-6937f3fb63ba","owner":[],"postedDate":"September 24th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":54816991,"name":"Health sciences/Health care"},{"id":54816992,"name":"Health sciences/Medical research"}],"tags":[],"updatedAt":"2026-03-16T06:26:27+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-24 23:05:46","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6840424","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6840424","identity":"rs-6840424","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}