key: cord-1052410-zoo0symq authors: Özüdoğru, Osman; Acer, Ömer; Genç Bahçe, Yasemin title: Risks of catching COVID‐19 according to vaccination status of healthcare workers during the SARS‐CoV‐2 Delta variant dominant period and their clinical characteristics date: 2022-04-23 journal: J Med Virol DOI: 10.1002/jmv.27778 sha: d4cbb85e5e16bb1c8c158c80586d7a6188473dc9 doc_id: 1052410 cord_uid: zoo0symq The exposure of healthcare workers (HCWs) to severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) has been a major concern since the beginning of the coronavirus disease 2019 (COVID‐19) pandemic. The study aimed to investigate the relationship between vaccination status and the status of catching COVID‐19 in HCWs working in a Training and Research Hospital in Turkey, and the clinical course of the disease in those who were caught. The vaccination status of 1279 HCWs working at Siirt Training and Research Hospital during the period when the SARS‐CoV‐2 Delta variant was dominant, their cases of catching COVID‐19 during this period, and the clinical course of the disease in patients with COVID‐19 were investigated retrospectively. We found that the rate of COVID‐19 transmission was lowest in fully vaccinated HCWs (p < 0.05). The rate of COVID‐19 transmission in HCWs who received two doses of BioNTech vaccine (4.4%) and two doses of CoronaVac+ one dose of BioNTech vaccines (2.7%) was considerably lower than those without vaccination (26.2%) (p < 0.05). The transmission rate was lowest among those vaccinated with two doses of CoronaVac+ one dose of BioNTech. Hospitalization was not required in fully vaccinated HCWs. The lymphocyte count was found to be significantly higher in fully vaccinated patients than incompletely vaccinated and unvaccinated patients. Although C‐reactive protein (CRP), d‐dimer, and ferritin values were higher in unvaccinated and partially vaccinated patients than in fully vaccinated patients, the differences were not statistically significant. As a result, the transmission rate of COVID‐19 was lowest in fully vaccinated HCWs and in those vaccinated with two doses of CoronaVac+ one dose of BioNTech. In fully vaccinated HCWs, hospitalization was not needed. | 1 COVID-19 pandemic. 4 COVID-19 vaccinations, combined with personal protective measures, have been deemed the most effective way to stop the virus from spreading. 5 While to date, nonpharmaceutical interventions for instance social distancing, face masks, and contact tracing have been the mainstay of health policy strategies to decrease the viral spread and limit requests for healthcare, new COVID-19 vaccines are starting to change that. 6 For existing vaccine-effectiveness estimates, the focus is on the BNT162b2 messenger RNA (mRNA) vaccine (Pfizer-BioNTech), the ChAdOx1 nCoV-19 vaccine (Oxford-AstraZeneca), and the mRNA-1273 vaccine (Moderna). [7] [8] [9] [10] In addition, the inactivated SARS-CoV-2 vaccine (CoronaVac) has been approved for emergency use in 22 countries, mostly low-and middle-income countries. Despite its global importance, evidence of the vaccine's efficacy or effectiveness is limited. 6 vaccine) vaccines are used in Turkey. 13 HCWs who have never been vaccinated are classified as unvaccinated. It was accepted that the protection of the vaccine started if at least 14 days had passed from the last dose of those who were fully vaccinated. At the time of the study, the protocol of the Ministry of Health did not include those who had COVID-19 in the vaccination program, as it accepted that they were immune for 6 months. Therefore, those who had COVID-19 in the 6 months before 15 July, 2021 were not included in the study. A total of 1279 healthcare professionals, 863 (67.4%) men, and 416 (32.5%) women, were included in our study. The mean age of men is 37.0 ± 9.0 and the mean age of women is 31.8 ± 6.5. Considering the COVID-19 vaccination status of HCW in our study, it was found that 590 (46.1%) were fully vaccinated, 403 (31.5%) were incompletely vaccinated, and 286 (22.4%) were unvaccinated. The mean age of the vaccine groups was 36 for those who were fully vaccinated, 32 for those who were incompletely vaccinated, and 31 for those who were unvaccinated, respectively. In the vaccine groups, the population and their mean age were higher in males than females. As can be seen in Table 1 , a significant difference was found between the vaccine groups in the number of people, mean age, gender ratios, and mean age of the sexes (p < 0.05). It was observed that 20 (Table 5 ). The results of CRP, lymphocyte, ferritin, and D-dimer, which are considered prognostic factors in patients with COVID-19, were compared and are shown in Table 6 . When these blood values were compared, a significant difference was found between the groups only for lymphocytes (p = 0.041). Fully vaccinated patients had a higher lymphocyte count than incompletely vaccinated and unvaccinated patients. Although CRP, D-dimer, and ferritin, which are used as prognostic factors, were found to be higher in unvaccinated and incompletely vaccinated patients compared to fully vaccinated patients, they were not found to be statistically significant (p > 0.05). In our study, oxygen support status and CT uptake rates were examined to compare the severity of lung involvement of those who T A B L E 1 Number of people, mean age, gender ratios, and mean age of genders among vaccine groups. 15 It was the first COVID-19 vaccine to receive an emergency use authorization by the US Food and Drug Administration. 16 The mRNA vaccine effectiveness of full immunization against COVID-19 was 90% regardless of symptoms in a prospective cohort of 3950 HCWs weekly tested for SARS-CoV-2 for 13 weeks under real-world conditions. Furthermore, after the first dose, vaccine effectiveness was at 80%. 9 In recent studies, Daniel et al., 17 23 In our study, a significant difference was observed between the fully vaccinated, incompletely vaccinated, and unvaccinated The authors declare no conflicts of interest. The data sets used and/or analyzed during the current study are available from the corresponding author on reasonable request. T A B L E 7 Oxygen support status and computed tomography (CT) uptake rates of those who had COVID-19 in the Delta variant dominant period. WHO. WHO Coronavirus (COVID-19). 2022. Accessed COVID-19 vaccine coverage in health-care workers in England and effectiveness of BNT162b2 mRNA vaccine against infection (SIREN): a prospective, multicentre, cohort study. 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