Cross-Reactive IgG Antibody Responses to SARS-CoV-2 in Older Adults Following Seasonal Coronavirus Infection in Jiangsu, China (2015-2017).

The extent of cross-reactive antibodies to SARS-CoV-2 elicited by seasonal human coronaviruses (HCoVs) remains unclear. We analyzed longitudinal preinfection and postinfection IgG responses in 62 older adults with PCR-confirmed HCoV infections from sera collected prior to the emergence of SARS-CoV-2. At baseline, 12.9% and 16.1% had low-titer antibodies against SARS-CoV-2 spike (S) or nucleocapsid (N) proteins, respectively, but postinfection increases were marginal. Our findings suggest seasonal HCoV infections induce limited SARS-CoV-2 cross-reactive antibodies in community-dwelling older adults.