CD79A and COVID-19: Therefore, we conducted a retrospective observational clinical study to examine the levels of anti-omicron-type SARS-CoV-2 IgG and IgA in Japanese pregnant women who received the mRNA-based COVID-19 vaccine (BNT162b2 XBB.1.5), known for its efficacy against omicron-type SARS-CoV-2 variants.