Flu vaccine makers plan switch to trivalent shots, removing vanished B virus
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Influenza vaccine manufacturers in the United States said this week that they have plans to remove a potentially extinct influenza B lineage from their vaccines and offer only trivalent shots next season.
Seqirus, which previously made three versions of a quadrivalent influenza vaccine, announced that it would remove B/Yamagata from all its influenza vaccines for the 2024-2025 season.
GSK told Healio in an email that it also plans to remove B/Yamagata from its vaccines and offer trivalent formulations next season after producing two quadrivalent shots last year.
Sanofi said it would be able to offer trivalent shots if there is a definitive switch from quadrivalent shots. (FDA advisors usually meet in March to select viruses for U.S. influenza vaccines.)
There has not been a confirmed infection with an influenza B/Yamagata virus since March 2020, according to WHO, which recommended last year that the B/Yamagata-lineage be dropped from seasonal influenza vaccines, which typically include two influenza A and two influenza B viruses.
WHO was not able to confirm recent reports of a few B/Yamagata infections as occurring naturally and said it is “unlikely” that B/Yamagata-lineage viruses are still circulating.
Several reasons have been given for the disappearance, including COVID-19 mitigation measures, although B/Yamagata viruses had declined in circulation even before the pandemic.
Because B/Yamagata has not been detected in more than 3 years, FDA vaccine advisors have also advocated for the lineage to be removed from U.S. vaccines.
References:
CDC. TABLE. Influenza vaccines — United States, 2023-24 influenza season. https://www.cdc.gov/flu/professionals/acip/2022-2023/acip-table.htm. Last reviewed Aug. 24, 2023. Accessed Feb. 9, 2024.
FDA. Influenza virus vaccine strain selection – 2024 Southern Hemisphere. https://www.fda.gov/media/172765/download. Published Oct. 5, 2023. Accessed Feb. 9, 2023.
Following FDA guidance, CSL Seqirus to remove B/Yamagata influenza virus strain from portfolio of influenza vaccines for the 2024/25 season. https://www.cslseqirus.us/news/csl-seqirus-to-remove-byamagata-influenza-virus-strain-from-portfolio-of-influenza-vaccines. Published Feb. 8, 2024. Accessed Feb. 9, 2024.
WHO. Questions and answers. Recommended composition of influenza virus vaccines for use in the Southern Hemisphere 2024 influenza season and development of candidate vaccine viruses for pandemic preparedness. https://cdn.who.int/media/docs/default-source/influenza/who-influenza-recommendations/vcm-southern-hemisphere-recommendation-2024/202309_qanda_recommendation.pdf?sfvrsn=7a6906d1_5. Published Sept. 29, 2023. Accessed Feb. 9, 2024.
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