Does a lack of vaccine side effects correlate with reduced BNT162b2 mRNA vaccine response among healthcare workers and nursing home residents?

Oyebanji, Oladayo A.; Wilson, Brigid; Keresztesy, Debbie; Carias, Lenore; Wilk, Dennis; Payne, Michael; Aung, Htin; Denis, Kerri St.; Lam, Evan C.; Rowley, Christopher F.; Berry, Sarah D.; Cameron, Cheryl M.; Cameron, Mark J.; Schmader, Kenneth E.; Balazs, Alejandro B.; King, Christopher L.; Canaday, David H.; Gravenstein, Stefan

BACKGROUND: The BNT162b2 SARS-CoV-2 mRNA vaccination has mitigated the burden of COVID-19 among residents of long-term care facilities considerably, despite being excluded from the vaccine trials. Data on reactogenicity (vaccine side effects) in this population are limited. AIMS: To assess reactogenicity among nursing home (NH) residents. To provide a plausible proxy for predicting vaccine response among this population. METHODS: We enrolled and sampled NH residents and community-dwelling healthcare workers who received the BNT162b2 mRNA vaccine, to assess local or systemic reactogenicity and antibody levels (immunogenicity). RESULTS: NH residents reported reactions at a much lower frequency and lesser severity than the community-dwelling healthcare workers. These reactions were mild and transient with all subjects experiencing more local than systemic reactions. Based on our reactogenicity and immunogenicity data, we developed a linear regression model predicting log-transformed anti-spike, anti-receptor-binding domain (RBD), and neutralizing titers, with a dichotomous variable indicating the presence or absence of reported reactions which revealed a statistically significant effect, with estimated shifts in log-transformed titers ranging from 0.32 to 0.37 (all p < 0.01) indicating greater immunogenicity in subjects with one or more reported reactions of varying severity. DISCUSSION: With a significantly lower incidence of post-vaccination reactions among NH residents as reported in this study, the BNT162b2 mRNA vaccine appears to be well-tolerated among this vulnerable population. If validated in larger populations, absence of reactogenicity could help guide clinicians in prioritizing vaccine boosters. CONCLUSIONS: Reactogenicity is significantly mild among nursing home residents and overall, subjects who reported post-vaccination reactions developed higher antibody titers. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40520-021-01987-9.