OBJECTIVE: This study aims to investigate the antibody response and the side effects of the two-dose inactive SARS-CoV-2 vaccine (CoronaVac, Sinovac, China) among a health care worker population in Turkey. METHODS:This study was a prospective, cross-sectional, single-center study conducted between December 16, 2020, and March 15, 2021. We evaluated the side effects from a questionnaire, and anti-spike immunoglobulin G response to the vaccine (0-and 28-day schedule) using an enzyme-linked immunosorbent assay.RESULTS: A total of 94 of 184 health care workers completed this study. The percentages of participants who were seronegative at baseline and achieved to the seropositivity were 21.3 and 97.9%, respectively, on day 21 after vaccinations. The seropositivity was predominantly detected in 31-45 years of the age group (55.4%, p=0.636), normal body mass index (47.8%, p=0.999), nonsmokers (64.1%, p=0.999), those without any comorbidities (73.9%, p=0.463), and those without any side effects (70.2%, p=0.256). The frequencies of overall side effects within seven days after the first and second doses of CoronaVac were 37.2 and 28.7%, respectively.The most common side effects was localized pain at the injection site (15.7 and 11.6%, respectively). CONCLUSIONS:We found that vaccination by two-dose CoronaVac could elicit a specific humoral response, and it was well tolerated in health care workers. The high seropositivity developed after the second dose attracted attention. Our study will be useful in terms of showing short-term immunity and side effects.