Evaluation of Reactogenicity and Neutralizing Antibody Responses 6 Months Post-Vaccination with Monovalent COVID-19...

The association between reactogenicity and long-term immunogenicity after coronavirus disease 2019 (COVID-19) vaccination remains unclear. This study investigated whether adverse reactions to ChAdOx1 nCoV-19 or BNT162b2 vaccines correlate with neutralizing antibody responses in severe acute respiratory syndrome coronavirus 2 infection-naïve healthcare workers. Blood samples were collected at three time points to measure neutralizing antibodies. Among 123 participants (ChAdOx1 nCoV-19, n=88; BNT162b2, n=35), local and systemic reactions were not significantly associated with antibody responses at six months post-vaccination for either vaccine type. No significant interactions between symptoms, time points, or age were observed. These findings suggest that adverse reactions might not predict long-term neutralizing antibody levels following COVID-19 vaccination.