Since our first and second-round serum sample collections were succeeded by the third and fourth COVID-19 pandemic waves in Ethiopia, respectively, we compared the levels of binding IgA antibodies to RBDs of the SARS-CoV-2 Delta and Omicron variants as well as to Wuhan-RBD in unvaccinated and BNT-vaccinated schoolchildren. This evidence concerns the gene CD79A and COVID-19.