evidence: - On Monday, Sept. 11, 2023, the FDA took action authorizing and approving the updated 2023–2024 monovalent XBB.1.5 variant mRNA COVID-19 vaccines by Moderna and Pfizer-BioNTech. On September 12, 2023, CDC recommended use of these updated 2023–2024 COVID-19 vaccines in all individuals ages 6 months and older. [...] With these FDA and CDC actions, the CDC COVID-19 Vaccination Program ended as of September 12, 2023, as it applied to the administration of the bivalent Moderna and Pfizer-BioNTech mRNA COVID-19 vaccines previously provided by the US Government (USG). Now, with FDA’s authorization on October 3, 2023, of the 2023–2024 Novavax COVID-19 Vaccine, Adjuvanted, the CDC COVID-19 Vaccination Program has fully ended as of October 3, 2023. All authorized/approved doses of COVID-19 vaccine in the United States are now the 2023–2024 formulas. [...] Bivalent (Original and Omicron BA.4/BA.5 variant) Moderna and Pfizer-BioNTech mRNA COVID-19 vaccines and ancestral (Original) Novavax COVID-19 vaccines should no longer be administered; 2023-2024 versions should be administered instead.