The Moderna vaccine is an mRNA vaccine originally approved for EUA by the FDA on December 18, 2020. In 2022, the vaccine was replaced with a bivalent formula aimed to prevent infection by the original strain of the virus and Omicron variants BA.4 and BA.5. The EUA was again amended on September 11, 2023, to include the 2023–2024 formula, which includes a monovalent (single) component that corresponds to the Omicron variant XBB.1.5. The original and bivalent vaccines are no longer in use. The 2023–2024 formula is authorized for individuals 6 months through 11 years of age to prevent COVID-19. SPIKEVAX (2023–2024 formula) is the licensed Moderna product for people 12 years and older.
This vaccine has similar effectiveness and similar side effects as the Pfizer vaccine. Based on clinical trials, the original Moderna vaccine was 94.1% effective at preventing COVID-19 infections in people receiving two doses.
