WHO Announces Influenza Vaccine Recommendations for 2026 Southern Hemisphere Season
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The World Health Organization (WHO) has released its recommendations for the composition of influenza vaccines for the 2026 southern hemisphere influenza season. these recommendations are crucial, serving as the foundation for national regulatory authorities, pharmaceutical companies, and other stakeholders in the development, production, and licensing of effective influenza vaccines. https://www.who.int/news/item/08-02-2024-who-recommends-influenza-vaccine-composition-for-2024-2025-northern-hemisphere-season The updated guidance reflects ongoing surveillance of circulating influenza viruses and aims to maximize vaccine effectiveness.
Key Recommendations for 2026
The WHO recommendations differentiate between egg-based and cell culture/recombinant protein/nucleic acid-based vaccines.
Egg-based vaccines should contain the following:
* A/Missouri/11/2025 (H1N1)pdm09-like virus
* A/Singapore/GP20238/2024 (H3N2)-like virus
* B/Austria/1359417/2021 (B/Victoria lineage)-like virus
Cell culture-, recombinant protein- or nucleic acid-based vaccines should contain:
* A/Missouri/11/2025 (H1N1)pdm09-like virus
* A/Sydney/1359/2024 (H3N2)-like virus
* B/Austria/1359417/2021 (B/Victoria lineage)-like virus
The Shift Towards Trivalent Vaccines and the B/Yamagata Lineage
A notable aspect of the WHO’s recommendations is the continued move towards trivalent influenza vaccines. The WHO’s influenza vaccine composition advisory committee has consistently stated, since September 2023, that including a B/Yamagata lineage antigen is no longer necessary. https://www.who.int/news/item/08-02-2024-who-recommends-influenza-vaccine-composition-for-2024-2025-northern-hemisphere-season This is due to the declining prevalence of B/Yamagata lineage viruses in circulating influenza strains.
For those still transitioning from quadrivalent vaccines (which include both B/Victoria and B/Yamagata lineages), the fourth component should be a B/Phuket/3073/2013-like virus. Importantly, the WHO will no longer provide updated recommendations specifically for the B/yamagata lineage component.
Pandemic Preparedness: Zoonotic Influenza
Beyond seasonal influenza, the WHO is also focusing on pandemic preparedness. Updated recommendations have been issued for the development of new candidate vaccine viruses for zoonotic influenza – influenza viruses that originate in animals but have the potential to infect humans and cause a pandemic. This proactive approach aims to ensure that effective vaccines can be rapidly developed and deployed in the event of a novel influenza outbreak.
Key takeaways
* Trivalent Focus: The WHO is strongly recommending a shift towards trivalent influenza vaccines, omitting the B/Yamagata lineage component.
* Strain Specificity: Specific viral strains have been identified for inclusion in both egg-based and cell culture/recombinant vaccines.
* Pandemic Preparedness: The WHO is actively working on developing candidate vaccines for zoonotic influenza viruses to prepare for potential pandemics.
* Regular Updates: These recommendations are updated annually based on global influenza surveillance data.
The WHO’s ongoing surveillance and recommendations are vital for protecting global public health against the ever-evolving threat of influenza.continued monitoring of circulating strains and adaptation of vaccine compositions will be crucial in minimizing the impact of seasonal and potential pandemic influenza outbreaks.