The World Health Organization (WHO) issued new recommendations on the composition of trivalent influenza vaccines for 2026 in the Southern Hemisphere this Friday, following a four-day briefing and consultation aimed at addressing the constant evolution of influenza viruses.
For egg-incubated vaccines, the WHO has recommended including a virus similar to the A/Missouri/11/2025 (H1N1)pdm09 virus, another similar to the A/Singapore/GP20238/2024 (H3N2) virus, and a final similar to the B/Austria/1359417/2021 virus (B/Victoria lineage).
For cell-culture, recombinant protein, or nucleic acid vaccines, the agency has requested the use of a virus similar to the A/Missouri/11/2025 (H1N1)pdm09 virus, one similar to the A/Sydney/1359/2024 (H3N2) virus, and another similar to the B/Austria/1359417/2021 (B/Victoria lineage).
In line with the four previous WHO recommendations since September 2023, the advisory committee has maintained its view that the inclusion of a B/Yamagata lineage antigen is no longer warranted and has reported that recommendations for this fourth component of quadrivalent vaccines, whose transition to trivalent vaccines has not yet been completed, will no longer be updated.
The WHO has also updated its recommendations for the development of new candidate viruses for zoonotic influenza vaccines, with a view to pandemic preparedness.
All of this is intended to serve as a basis for national and regional regulatory authorities, pharmaceutical manufacturers, and other stakeholders to develop, produce, and license influenza vaccines for the upcoming season.
