Therefore, we investigated which specific anti-SARS-CoV-2 antibodies (IgG, IgA, and IgM) were present in saliva and the corresponding serum samples after vaccination with the BNT162b2 COVID-19 mRNA vaccine (Pfizer-BioNTech) in a prospective cohort of health care personnel at 2 and 6 months after first vaccination dose. Here, CD40LG is linked to COVID-19.