COVID-19 VACCINES MAY ALSO BOOST IMMUNITY TO SEASONAL CORONAVIRUSES AND INFLUENZA.

Abstract

Intro: The incidence of seasonal influenza reduced significantly during the COVID-19 pandemic, only to rebound in 2022. Although the global rollout of COVID-19 vaccines has significantly reduced the number of patients with severe COVID-19 disease and mortality, it is unclear whether COVID-19 vaccines could also confer protection against seasonal coronaviruses (HCoV) and influenza. Methods: We designed a pre-post study involving 142 adults (mean age 47.5 years, 61% women) who had blood samples collected before, and 6 months after their first dose of COVID-19 mRNA vaccine. IgG levels to the spike and nucleocapsid components of different variants of HCoV (HCoV-NL63, HCoV-HKU-1, HCoV-229E (S1 subunit) and HCoV-OC43 (S1+S2 ECD)) and also antihemagglutinin (HA) titres were determined for Influenza A H1N1 (A/California/06/2009), H1N1 (A/Michigan/45/2015), H3N2 (A/Switzerland/9715293/2013) and H3N2 (A/Hong Kong/45/2019) using an ELISA method, based on previously published protocols. Data were compiled in Microsoft EXCEL and antibody levels were compared using Vassar Stats (Vassar, USA). Findings: There was significant increase in the antibody levels 6 months after COVID-19 vaccination against S protein of HCoV-OC43 and HCoV-229E (both p<0.001) and N-protein of HCoV-NL63 (p<0.001). For Influenza A, H3N2/Hong Kong (p<0.01) showed significant rise in the antibody level post COVID-19 vaccination. There were some gender and inter-ethnic differences as well amongst these individuals with higher rises in females (S-prot: HCoV-OC43 (p<0.01), HCoV-229E (p<0.001); N-prot: HCoV-NL63 (p=0.005); Influenza A H3N2 (p<0.001)) and for those who identified as ethnic Chinese (S-prot: HCoVOC43 & HCoV-229E (p<0.001); N-prot: HCoV-NL63 (p=0.002); Influenza A H3N2 (p<0.001)). Conclusion: Cross protection from COVID-19 vaccination may partly explain the lower incidence of influenza infection during this pandemic although its mechanism is not clear. An increase in immunity to HCoV infection following COVID-19 vaccination could support feasibility of future development of a pancoronavirus vaccine.