2026 Southern Hemisphere Influenza Vaccine Composition Recommendations

The World Health Organization (WHO) today announced its recommendations for the viral composition of influenza vaccines for use in the 2026 influenza season in the southern hemisphere. The announcement was made at an Information Meeting following a 4-day Consultation on the Composition of Influenza Virus Vaccines.

Given the constantly evolving nature of influenza viruses, regular updates to vaccine composition are essential to ensure their effectiveness and to protect public health worldwide.

WHO convenes these consultations twice a year – once for the southern hemisphere and once for the northern hemisphere. This gathering includes an advisory group of experts from WHO Collaborating Centres and Essential Regulatory Laboratories. The group examines surveillance data and other information supplied by the WHO Global Influenza Surveillance and Response System (GISRS) and its partners to guide its recommendations.

WHO’s recommendations serve as the foundation for national and regional regulatory authorities, pharmaceutical manufacturers, and other stakeholders to develop, produce, and license influenza vaccines for the upcoming season.

WHO recommends that trivalent vaccines for use in the 2026 southern hemisphere influenza season contain the following:

Egg-based vaccines are produced using the fertilized eggs of hens. This method has been traditionally utilized for developing several vaccines, most notably the influenza vaccine. In this process, the virus is injected into the egg, where it replicates. Following a designated incubation period, the fluid from the egg containing the virus is harvested, inactivated, or attenuated, and then formulated into a vaccine. Egg-based production methods have been valued for their capacity to produce large quantities of vaccine and have been in use for decades. However, there are some limitations, including potential allergies in individuals who are sensitive to egg proteins. Despite this, egg-based vaccines are essential in protecting public health against various infectious diseases.

Cell culture, recombinant protein, or nucleic acid-based vaccines.

Consistent with the four prior WHO recommendations since September 2023, the WHO influenza vaccine composition advisory committee asserts that the inclusion of a B/Yamagata lineage antigen is no longer necessary.

Quadrivalent vaccines, in instances where the transition from trivalent vaccines has not been fully completed, incorporate a fourth component – a B/Yamagata lineage virus (similar to the B/Phuket/3073/2013 virus).

There will no longer be updated recommendations concerning the B/Yamagata lineage component.

WHO has also updated its recommendations for the generation of new candidate vaccine viruses for zoonotic influenza, emphasizing pandemic preparedness.