Historical annual reformulations of the influenza vaccine

Influenza (flu)
H1N1 virus
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Vaccines
Treatment
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Since 1999, the World Health Organization (WHO) has issued annual recommendations for influenza vaccine formulations. One reformulation of the influenza vaccine is for the Northern Hemisphere, and the other is for the Southern Hemisphere.[1] Both recommendations are trivalent, i.e. featuring three strains.[2]

Since the 2012–2013 season, the WHO recommendations have also included the formulation of an annual quadrivalent vaccine, featuring an additional strain of Influenza B virus, B/Yamagata.[2]

Due to the widespread use of non-pharmaceutical interventions at the beginning of the COVID-19 pandemic, the B/Yamagata influenza lineage has not been isolated since March 2020, and may have been eradicated. Starting with the 2024 Southern Hemisphere influenza season, the WHO and other regulatory bodies have removed this strain from influenza vaccine recommendations.[3][4][5]

  1. ^ Anker M, Schaaf D, World Health Organization (2000). WHO report on global surveillance of epidemic-prone infectious diseases (PDF) (Report). World Health Organization (WHO). hdl:10665/66485. WHO/CDS/CSR/ISR/2000.1. Archived (PDF) from the original on 31 October 2022.
  2. ^ a b Rudenko L, Kiseleva I, Krutikova E, Stepanova E, Rekstin A, Donina S, et al. (3 December 2018). "Rationale for vaccination with trivalent or quadrivalent live attenuated influenza vaccines: Protective vaccine efficacy in the ferret model". PLOS ONE. 13 (12) e0208028: e0208028. Bibcode:2018PLoSO..1308028R. doi:10.1371/journal.pone.0208028. PMC 6277076. PMID 30507951.
  3. ^ Schnirring L (29 September 2023). "WHO advisers recommend switch back to trivalent flu vaccines". Center for Infectious Disease Research and Policy. Archived from the original on 18 December 2023. Retrieved 23 January 2024.
  4. ^ "Use of Trivalent Influenza Vaccines for the 2024-2025 U.S. flu season". U.S. Food and Drug Administration (FDA). 5 March 2024. Archived from the original on 7 March 2024. Retrieved 7 March 2024. Public Domain This article incorporates text from this source, which is in the public domain.
  5. ^ "EU recommendations for 2024/2025 seasonal flu vaccine composition". European Medicines Agency (EMA). 26 March 2024. Archived from the original on 28 March 2024. Retrieved 28 March 2024.