RESUMO
OBJECTIVE: It is accepted that the only way to end severe acute respiratory syndrome coronavirus 2 epidemic is through community vaccination. The frequency and clinical features of infection after vaccination are not known clearly. The aim of this study is to determine the frequency and clinical features of coronavirus disease 2019 seen after either the first or second dose of CoronaVac vaccination in healthcare workers and their relatives. MATERIAL AND METHODS: This is a cross-sectional retrospective survey study. The study was carried out in 2013 volunteers, including 1903 (94.5%) healthcare workers and 110 (5.5%) relatives of healthcare workers. The frequency and clinical features of coronavirus disease 2019 before and after the first or second dose of CoronaVac vaccination were retrospectively evaluated using an online questionnaire conducted in July 2021. RESULTS: A total of 2013 people, 1312 women and 701 men, participated in the study. Of these individuals, 245 (12.1%) were polymerase chain reaction positive for coronavirus disease 2019 before vaccination. Of this group, 185 (75.5% of polymerase chain reaction positives and 9.1% of the whole population) received home-based therapy, while 38 (15.5%) received hospital admission. Asymptomatic polymerase chain reaction positivity before vaccination was seen in 22 (9%) individuals. There were 177 (8.8%) participants who developed polymerase chain reaction positivity at any time after vaccination. In 129 (72.8%) of these participants, polymerase chain reaction positivity occurred 21 days after the second dose of vaccine. While the number of patients hospitalized before vaccination was 38 (15.5% of the polymerase chain reaction positivity group and 1.89% of the general population), the number of patients hospitalized after the vaccination was 17 (10.1% of the polymerase chain reaction positivity group and 0.80% of the general population). The decrease in hospitalization proportion was statistically significant (P = .002). CONCLUSION: The frequency of coronavirus disease 2019, severe illness, and hospitalization rates were found to be lower in postvaccination period. The vaccine is effective in preventing coronavirus disease 2019 and severe disease.
RESUMO
Background: As vaccination against coronavirus disase-19 (COVID-19) evolves, hesitancy has become a problematic issue that has gradually spread worldwide. The main reason for vaccine hesitancy is uncertainties about vaccine side effects. Aims: To evaluate the safety of an inactivated COVID-19 vaccine, CoronaVac, and determine the risk factors of emergence of side effects. Study Design: Cross-sectional study. Methods: An online questionnaire was administered via the internet to healthcare workers who received one or two doses of CoronaVac. The online survey consisted of three sections detailing sociodemographic data, COVID-19 history, and post-vaccine side effects. Side effects that occurred in the period starting from immediately after the first vaccination to the end of the 14th day after the second vaccination were recorded. Results: A total of 1628 healthcare workers responded to the online survey. Of these, 24.3% had a side effect either after the first or second dose of CoronaVac. Redness and/or pain at the inoculation site, headache, muscle and joint pains, palpitations, and dizziness were the most common side effects. Female sex, age <50 years, and thyroid disorder in the pre-vaccine period were found to be risk factors for the emergence of side effects. Blood pressure control could not be achieved in 2.2% of participants despite medication use, and permanent medication was needed in 2.5% of participants for blood pressure control. Conclusion: Almost a quarter of healthcare workers have at least one side effect after the first or second dose of CoronaVac. Female gender, age <50 years, and thyroid disorder appear to be risk factors for the occurrence of side effects.