Flu Season 2026-2027: What the Latest WHO Recommendations Mean for You
The World Health Organization (WHO) has released its recommendations for influenza vaccine composition for the 2026-2027 northern hemisphere influenza season, following a four-day consultation with global experts. These recommendations are crucial, as influenza viruses are constantly evolving, necessitating regular vaccine updates to ensure optimal protection.
The Shifting Landscape of Influenza Viruses
Influenza vaccine composition is regularly updated because of the constant changes in influenza viruses. The WHO’s recommendations guide pharmaceutical companies and national regulatory agencies in developing effective vaccines for the upcoming season. This collaborative effort aims to match vaccines closely with circulating viruses, maximizing protection against severe illness, and death.
A significant development leading into these recommendations was the emergence of a distinct A(H3N2) variant, classified as J.2.4.1 (also known as “subclade K”), in August 2025. This variant spread rapidly worldwide, contributing to an earlier-than-usual start to the flu season and higher-than-usual activity levels in many countries. Subclade K became the dominant influenza virus reported across regions.
WHO’s 2026-2027 Vaccine Recommendations
The WHO’s recommendations differ slightly depending on the vaccine production method.
Egg-Based Vaccines
- A/Missouri/11/2025 (H1N1)pdm09-like virus
- 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
- A/Missouri/11/2025 (H1N1)pdm09-like virus
- A/Darwin/1415/2025 (H3N2)-like virus
- A B/Pennsylvania/14/2025 (B/Victoria lineage)-like virus
The Ongoing Threat of Zoonotic Influenza
Beyond seasonal influenza, experts are closely monitoring zoonotic influenza viruses – those circulating in animals that can infect humans. These viruses pose a pandemic threat, and the WHO’s Global Influenza Surveillance and Response System (GISRS) plays a vital role in identifying and assessing these risks.
Since September 23, 2025, 25 human infections with zoonotic influenza viruses were reported from six countries. These cases typically involved exposure to infected animals or contaminated environments, with no evidence of human-to-human transmission. The WHO recommended the development of a new candidate vaccine virus (CVV) for an A(H9N2) virus as a proactive measure.
The Power of Global Surveillance
The WHO’s GISRS, established in 1952, remains the longest-standing global platform for systematic disease surveillance. This system brings together experts from WHO Collaborating Centres and Essential Regulatory Laboratories to analyze data and inform vaccine development. Dr. Tedros Adhanom Ghebreyesus, WHO Director-General, emphasized the importance of shared action in addressing global health risks like influenza.
Frequently Asked Questions
What is GISRS? The Global Influenza Surveillance and Response System (GISRS) is a WHO-coordinated network of laboratories that monitor influenza viruses worldwide.
Why do flu vaccines need to be updated every year? Influenza viruses constantly change, so vaccines must be updated to match the circulating strains and provide the best possible protection.
What is a candidate vaccine virus (CVV)? A CVV is a virus selected by the WHO that can be used to rapidly manufacture vaccines if a pandemic threat arises.
What is zoonotic influenza? Zoonotic influenza refers to influenza viruses that originate in animals and can infect humans, potentially causing pandemics.
How common is the flu? We find around a billion cases of seasonal influenza annually, leading to 3–5 million cases of severe illness and an estimated 290,000 to 650,000 respiratory deaths each year.
Pro Tip: Staying informed about the latest influenza recommendations and getting vaccinated annually are the most effective ways to protect yourself and your community from the flu.
Did you know? The WHO conducts consultations twice a year, once for each hemisphere, to ensure vaccines are tailored to the specific viruses expected to circulate in each region.
Stay tuned for further updates on influenza vaccine availability and recommendations from your local health authorities. To learn more about influenza and how to protect yourself, visit the World Health Organization’s influenza website.
