SARS-CoV-2 antibodies: comparison of three high-throughput immunoassays versus the neutralization test.

On March 11, 2020 the World Health Organization (WHO) declared the novel coronavirus (SARS-CoV-2) outbreak a global pandemic.1 Currently, no specific therapy has proved to be effective against the infection. With the approval by WHO2 of the first vaccine for emergency use against SARS-CoV-2 on December 31, 2020, it is important to understand the strength and duration of immunity after administration, which is induced by neutralizing anti-SARS-CoV-2 S antibodies (nAbs).3 The same antibodies are also present in individuals once the SARS-CoV-2 infection is resolved, at levels that depend on the duration and severity of clinical symptoms.4 The efficacy of passive antibody therapy has been associated with the concentration of nAbs in the convalescent plasma (CP) of recovered patients.5,6 Thus, it would be useful to immediately identify donors with high nAbs titers. The gold-standard test used to detect nAbs is the plaque reduction neutralization test (PRNT).