Abrysvo + PF-07252220

**Abrysvo + PF-07252220** is a combination of Abrysvo, a bivalent recombinant protein vaccine approved for preventing RSV lower respiratory tract disease (LRTD) in adults ≥60 years and infants via maternal immunization at 32-36 weeks gestation, and PF-07252220, an investigational quadrivalent mRNA vaccine targeting influenza A/H1N1, A/H3N2, B/Victoria, and B/Yamagata strains in adults. Abrysvo, developed by Pfizer, contains stabilized prefusion F proteins from RSV subgroups A and B, expressed in Chinese hamster ovary cells, inducing neutralizing antibodies against RSV prefusion F glycoprotein to block viral entry. PF-07252220, also from Pfizer, uses modified mRNA to encode influenza hemagglutinin (HA) antigens, stimulating immune responses including hemagglutination inhibition (HAI) antibodies; it is in Phase 3 for influenza prophylaxis. No specific clinical data on this exact combination exists, but both are intramuscular vaccines from Pfizer, potentially for co-administration in high-risk adults to address RSV and influenza.