ABSTRACT
Definition of SARS-CoV-2 antibody responses is essential to verify protective immunity following infection and vaccination. Here, we devised a versatile serological test, named ABCORA, that is based on a multifactorial analysis of SARS-CoV-2 and circulating human coronavirus (HCoV) antibody responses. Utilizing empirical tailored cut-offs and computational approaches based on training and validation cohorts comprising pre-pandemic (N=825) and SARS-CoV-2 infected plasma donors (N=389), we defined several analysis strategies that allow a highly accurate definition of SARS-CoV-2 seroconversion and prediction of neutralization activity. Intriguingly, HCoV reactivity was significantly higher in SARS-CoV-2 negative donors. Amongst SARS-CoV-2 infected individuals, elevated SARS-CoV-2 responses were linked to higher HCoV activity suggesting that pre-existing HCoV immunity may confer protection against SARS-CoV-2 acquisition and promote development of SARS-CoV-2 specific antibody responses. Deciphering interdependencies between SARS-CoV-2 and HCoV immunity should be enforced as understanding their impact on infection may allow soliciting cross-protective activities for broader coronavirus prevention.