To evaluate the symptoms and laboratory parameters of patients admitted to the emergency department after CoronaVac (Sinovac) vaccination. Complaints, demographic characteristics, laboratory tests, interventions, and outcomes of patients admitted to the emergency department within seven days of receiving the CoronaVac (Sinovac) were all evaluated. Pain at the injection site, swelling, redness, and pain in the injected arm were expected side effects of the vaccination. In this study, a total of six people had syncope following the vaccination, one of whom developed an allergic reaction. The most common adverse events in non-geriatrics were fatigue, headache, fever, and abdominal pain, while in geriatric patients’ fatigue, headache, chest pain, and dyspnea were most common, with fever falling in the last place. Rare symptoms following vaccination included syncope and urticaria. It is necessary to be prepared for the side effects that may occur during mass vaccination against COVID-19. In this study, the body’s response to the vaccine in geriatric patients was atypical in vital signs and laboratory values.