Adverse Events in Following Immunization with Inactivated SARS-CoV-2 Vaccines (TURKOVAC and CoronaVac) in PCR-Positive Asymptomatic or Mildly Symptomatic Individuals Compared to PCR-Negative Recipients

Background/Objectives: COVID-19 vaccines may be given without requiring a negative test or absence of symptoms; however, this recommendation needs further safety evaluation. This study aimed to compare the adverse events following immunization (AEFI) between PCR-positive (asymptomatic/mildly symptomatic) and PCR-negative individuals at the time of vaccination, with a secondary objective of comparing the two vaccines (TURKOVAC and CoronaVac). Methods: This descriptive study was a secondary analysis of phase III clinical trials. Individuals who were positive for SARS-CoV-2 PCR at the time of vaccination constituted the PCR(+) group and those who tested negative or became positive after the 4th day following vaccination constituted the PCR(-) group. Whether participants had a history of COVID-19 was not considered. Results: Data from 5207 individuals were analyzed. AEFIs were more frequent in the PCR(+) group than PCR(-) group: site pain (24.5% vs. 16.7%, p < 0.001), arm pain (9.5% vs. 7.8%, p = 0.008), headache (14.8% vs. 10.0%, p < 0.001), fatigue (14.5% vs. 8.9%, p < 0.001), myalgia (12.3% vs. 7.5%, p < 0.001), sore throat (11.9% vs. 8.1%, p < 0.001), cough (7.9%; 11.1% vs. 6.9%, p < 0.001). These AEFIs were more frequent in the PCR(+) group with both vaccine groups separately. The distribution of AEFIs over time followed similar patterns in PCR(+) and PCR(-) individuals. Local AEFIs were slightly more common with the TURKOVAC, systemic AEFIs with the CoronaVac. Conclusions: While AEFIs were more common among PCR(+) group, they were mild, tolerable, and easily manageable. Our results support the suggestion that routine PCR testing prior to vaccination may not be warranted solely to mitigate concerns about anticipated adverse events.