Anaphylaxis is rare due to CoronaVac in a population of healthcare workers

BACKGROUND: CoronaVac, the first coronavirus disease 2019 vaccine administered in our country, was found safe in clinical trials. OBJECTIVE: We aimed to reveal the rate and features of CoronaVac vaccine-associated allergic reactions among vaccinated healthcare workers (HCWs) in real-life. METHODS: This study was planned as a questionnaire-based study. Participants who reported a postvaccination allergic reaction were interviewed on phone and their medical records were also checked for confirmation. RESULTS: A total of 2,488 HCWs took part in the study and 4,054 postvaccination complete questionnaire-responses were obtained. Twenty-one HCWs (female: male, 17:4) with a mean age of 40.95 ± 10.09 stated that they had an allergic reaction after a total of 23 vaccine injections. Accordingly, the reaction rate was 0.56% among all vaccine doses. The most common reactions were systemic skin reactions (2.7%) consisting of generalized pruritus, diffuse pruritic erythema, urticaria, and maculopapular rash. That was followed by local injection site reaction (0.12%). Anaphylaxis was reported in 4 cases (0.09%) with a mean onset time of 12 ± 6 minutes. One of them had a history of anaphylaxis with 2 drugs, another had venom and food allergy. Three of the subjects had level 2 diagnostic certainty according to the Brighton Collaboration criteria and one had level 3. All anaphylaxis cases were discharged within 24 hours and none of them required intensive care. CONCLUSION: Our study demonstrated that allergic reactions to CoronaVac were rare and mostly mild. Although anaphylaxis was also rare, the importance of early intervention with close follow-up was once again emphasized.