Seasonal human coronavirus antibodies are boosted upon SARS-CoV-2 infection but not associated with protection

Anti-SARS-CoV-2 antibodies against Spike- and Nucleo-proteins were determined in human sera from patients in Philadelphia collected before COVID-19 pandemic (2017). These antibodies showed the cross reactivity between for previously circulating coronavirus (OC43, 229E and NL63) and for SARS-CoV-2. However, these antibodies did not contribute to the protection against SARS-CoV-2 infection. The SARS-CoV-2 infection enhanced the induction of not only anti-SARS-CoV2 antibody but also anti-OC43 antibody.