Three vaccinations against SARS-CoV-2 are absolutely required in RA patients to elicit antiviral antibody response in the oral cavity

Preexisting autoimmune diseases, such as rheumatoid arthritis, and biological treatments, like B cell depletion, are known to exhibit higher risk of severe COVID-19 manifestation and increased frequency of breakthrough infections after vaccination.  Systemic serum antibodies after vaccination restrict virus dissemination after infection of the host, while virus-specific antibodies at the mucosal surfaces, i.e. oral cavity, are required to prevent initial infection of the host.  The recent study published by Drs. Ana-Luisa Stefanski and Dr. Andrey Kruglov in Journal of Autoimmunity addressed the kinetic of anti-SARS-CoV-2 antibody responses in oral cavity in RA patients. They found that anti-Spike SARS-CoV-2 IgG responses after second vaccination were severely diminished in the oral cavity of RA patients regardless of B cell depleting therapy. Importantly, both salivary and serologic anti-Spike IgG and IgA responses towards WT and omicron Spike variants were efficiently induced by third vaccination in RA patients to the levels that were similar to healthy individuals. Altogether, these data advocate for the necessity of three-dose vaccination for RA patients to mount anti-Spike antibody responses at the mucosal surfaces.