Correlates of protection against SARS-CoV-2 infection and COVID-19 disease

Antibodies against epitopes in S1 give the most accurate CoP against infection by the SARS-CoV-2 coronavirus. Measurement of those antibodies by neutralization or binding assays both have predictive value, with binding antibody titers giving the highest statistical correlation. However, the protective functions of antibodies are multiple. Antibodies with multiple functions other than neutralization influence efficacy. The role of cellular responses can be discerned with respect to CD4(+) T cells and their augmentation of antibodies, and with respect to CD8(+) cells with regard to control of viral replication, particularly in the presence of insufficient antibody. More information is needed on mucosal responses.