Since vaccine efficacy appears largely dependent on anti-SARS-CoV-2 neutralizing antibodies titer [7], the sharpest decline and larger seronegativization of IgA anti-SARS-CoV-2 S1 observed in our population of healthcare workers precisely mirrors the considerable decrease of protection against the risk of developing any type of SARS-CoV-2 infection (either asymptomatic or symptomatic) seen in recent epidemiological studies, whereby this class of antibodies constitutes the primary mucosal defense against many infectious (especially respiratory) diseases [16, 17]. This evidence concerns the gene CD79A and respiratory system disorder.