Tozinameran/Famtozinameran

**Semantic type:** Pharmacologic Substance

**Definition:** A bivalent booster vaccine consisting of tozinameran, a lipid nanoparticle (LNP) encapsulating a nucleoside modified messenger RNA (modRNA) encoding an optimized form of the full-length viral spike (S) glycoprotein of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Wuhan-Hu-1 strain (Original), and famtozinameran, a LNP encapsulating a modRNA encoding an optimized form of the full-length viral S protein of the SARS-CoV-2 Omicron variant lineages BA.4 and BA.5 (Omicron BA.4/BA.5), with potential immunizing and anti-COVID-19 activities. Upon injection of famtozinameran/tozinameran, the LNPs bind to the plasma membrane of nearby cells and release SARS-CoV-2 S protein mRNA into the cells. The mRNA is then translated by the cellular protein translation machinery to produce SARS-CoV-2 S protein. This may activate both humoral and cellular immune responses which may result in protection against SARS-CoV-2 infection.

**Synonyms:** - Famtozinameran/Tozinameran - Pfizer/BioNTech COVID-19 Vaccine, Bivalent, US - Tozinameran/Lipid Nanoparticle-encapsulated mRNA-based Omicron BA.4/BA.5 Bivalent SARS-CoV-2 Vaccine