WHO Announces Influenza Vaccine Recommendations for 2026-2027 Season
The World Health Organization (WHO) has released its recommendations for the composition of influenza vaccines aimed at the northern hemisphere’s 2026-2027 influenza season. This decision follows an extensive four-day consultation that reviewed global influenza surveillance data.
Updating the vaccine formulation is essential due to the continual evolution of influenza viruses. WHO’s guidance is crucial for vaccine regulatory agencies and pharmaceutical manufacturers worldwide as they develop, produce, and authorize flu vaccines for the upcoming season. This effort is vital to ensure that vaccines align closely with the circulating viruses, thereby providing optimal protection against severe illness and fatalities.
These consultations, held twice a year for the northern and southern hemispheres, gather experts from WHO’s Collaborating Centres and Essential Regulatory Laboratories within the Global Influenza Surveillance and Response System (GISRS). Their role is to review and analyze data collected by GISRS and its partners.
Dr. Tedros Adhanom Ghebreyesus, WHO Director-General, noted, “Influenza viruses evolve continuously, reminding us of our global interconnectedness. Shared risks necessitate collective action. WHO’s vaccine composition recommendations are based on the ongoing efforts of the GISRS and partners, enabling next season’s vaccines to be adjusted for the latest virus strains and enhancing community protection.”
Seasonal Influenza Overview
In August 2025, a notable variant of the A(H3N2) virus appeared, designated as J.2.4.1 or “subclade K.” It circulated rapidly around the world and led to an earlier onset of the flu season in various countries, with many reporting unusually high activity levels. This variant accounted for the lion’s share of influenza viruses detected across regions.
Influenza A viruses were mostly prevalent, with additional variants of A(H3N2) and A(H1N1) also identified. There were low incidences of influenza B viruses (B/Victoria lineage) reported, and interestingly, no cases of the B/Yamagata lineage have been noted since March 2020.
Zoonotic Influenza Concerns
Experts also examined the circulation of influenza viruses in animals, focusing on those that have led to human infections. Zoonotic influenza viruses pose a significant risk due to their potential to trigger pandemics.
Since September 23, 2025, WHO received reports of 25 human cases of zoonotic influenza across six countries. Most of these individuals had contact with infected animals or contaminated environments. No instances of human-to-human transmission were reported.
These biannual consultations entail a thorough assessment of these viruses as well as the selection of new candidate vaccine viruses (CVVs) to quickly produce vaccines in response to potential pandemic threats. During this round, experts recommended the development of a new CVV for an A(H9N2) virus.
Recommended Vaccines for 2026-2027 Season
Egg-Based Vaccines
- An A/Missouri/11/2025 (H1N1)pdm09-like virus;
- An A/Darwin/1454/2025 (H3N2)-like virus; and
- A B/Tokyo/EIS13-175/2025 (B/Victoria lineage)-like virus.
Cell Culture-, Recombinant Protein-, or Nucleic Acid-Based Vaccines
- An A/Missouri/11/2025 (H1N1)pdm09-like virus;
- An A/Darwin/1415/2025 (H3N2)-like virus; and
- A B/Pennsylvania/14/2025 (B/Victoria lineage)-like virus.
Seasonal influenza is a common acute respiratory infection caused by influenza viruses and affects people worldwide. There are roughly a billion cases each year, including between 3 to 5 million severe cases, leading to an estimated 290,000 to 650,000 respiratory deaths annually.
The WHO has operated the Global Influenza Surveillance and Response System (GISRS) since 1952, making it one of the longest-running platforms for systematic disease surveillance globally.
