We know that mRNA vaccines, in particular Pfizer-BioNTech (BNT162b2,Comirnaty) and Moderna (mRNA-1273, Spikevax), provide up to 95% protection against COVID-19 (1, 2), but the level of specific neutralizing antibodies against the S protein diminish over time. The gene discussed is PROS1; the disease is COVID-19.