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WHO Releases 2026-2027 Northern Hemisphere Influenza Vaccine Recommendations

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WHO Publishes 2026-2027 Northern Hemisphere Flu Vaccine Recommendations

The World Health Organization (WHO) has published its recommendations for the viral composition of influenza (flu) vaccines for the 2026-2027 northern hemisphere season. These guidelines follow a four-day consultation where experts analyzed global influenza surveillance data. The recommendations aim to guide national vaccine regulatory agencies and pharmaceutical companies in developing and producing vaccines that are closely matched to anticipated circulating viruses, thereby offering protection against severe illness and mortality.

The WHO's recommendations serve to inform the global process of vaccine development, production, and licensing, ensuring that vaccines are as effective as possible against the influenza strains expected to circulate in the upcoming season.

Overview of WHO's Recommendation Process

Influenza viruses are subject to constant change, necessitating regular updates to vaccine compositions. These biannual consultations, conducted for both the northern and southern hemispheres, gather specialists from WHO Collaborating Centres and Essential Regulatory Laboratories. These experts meticulously review and analyze data generated by the WHO Global Influenza Surveillance and Response System (GISRS) and its partners.

Dr. Tedros Adhanom Ghebreyesus, WHO Director-General, highlighted the continuous efforts of GISRS in updating vaccine strains to enhance community protection against globally evolving influenza viruses.

Seasonal Influenza Activity: A(H3N2) Variant Emerges

In August 2025, a distinct variant of the A(H3N2) virus, classified as J.2.4.1 or "subclade K," emerged and rapidly spread worldwide. This variant contributed to an earlier onset of the influenza season in several countries, with many reporting elevated activity levels. 'Subclade K' accounted for the majority of reported influenza viruses across various regions.

Overall, influenza A viruses were predominant, encompassing other variants of A(H3N2) and A(H1N1). Low levels of influenza B viruses (B/Victoria lineage) were detected, while no B/Yamagata lineage viruses have been reported since March 2020.

Addressing Zoonotic Influenza Concerns

During the consultation, experts also assessed influenza viruses circulating in animal populations that have caused human infections. These zoonotic influenza viruses are considered a significant public health concern due to their potential to cause pandemics.

Since September 23, 2025, a total of 25 human infections with zoonotic influenza have been reported to the WHO from six countries. Most of these cases were linked to exposure to infected animals or contaminated environments, with no reported instances of human-to-human transmission.

The meeting concluded with a recommendation to develop a new candidate vaccine virus (CVV) for an A(H9N2) virus, enabling rapid manufacturing if a pandemic threat were to emerge.

2026-2027 Northern Hemisphere Vaccine Compositions Recommended

For vaccines intended for use in the 2026-2027 northern hemisphere influenza season, the WHO recommends the following:

  • Egg-based vaccines:

    • An A/Missouri/11/2025 (H1N1)pdm09-like virus.
    • An A/Darwin/1454/2025 (H3N2)-like virus.
    • 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.
    • A B/Pennsylvania/14/2025 (B/Victoria lineage)-like virus.

Seasonal influenza, an acute respiratory infection caused by influenza viruses, is prevalent globally. It is estimated to result in approximately one billion cases annually, including 3–5 million severe cases, and an estimated 290,000 to 650,000 respiratory deaths each year.