Thunder Bay – The World Health Organization (WHO) has announced the recommended viral composition for influenza vaccines intended for the 2026 southern hemisphere flu season.
While this may seem far removed from life in Northwestern Ontario, decisions like this are key indicators of what could be expected in our own 2026–2027 flu season. They also offer a glimpse into global preparedness efforts for future pandemics — something Thunder Bay’s health sector and residents can’t afford to ignore.
The recommendations were made September 26, 2025, following a four-day consultation with experts from the WHO Global Influenza Surveillance and Response System (GISRS). These global influenza experts analyze surveillance data to decide which viral strains should be included in seasonal flu vaccines.
Vaccine Components for 2026
For trivalent vaccines (three-component versions), the WHO has recommended the following:
Egg-based Vaccines:
-
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-based, recombinant, or nucleic acid-based Vaccines:
-
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 update confirms no inclusion of the B/Yamagata lineage, a move consistent with WHO’s position since September 2023. This lineage is believed to be extinct, prompting the global health body to stop updating recommendations for its inclusion in vaccines.
Quadrivalent vaccines — those still using four flu strains — may still contain the B/Phuket/3073/2013-like virus, but these are expected to phase out as trivalent formulations take precedence.
What This Means for Thunder Bay
While this announcement targets the southern hemisphere, Canada’s own flu vaccine recommendations often reflect global surveillance trends. Local public health authorities and vaccine manufacturers use WHO data to prepare for future flu seasons, and monitoring southern hemisphere outbreaks offers a preview of what Thunder Bay could facemonths later.
This information is particularly important for Northwestern Ontario’s vulnerable populations, including seniors, those with chronic illnesses, and Indigenous communities where access to rapid healthcare may be more limited.
Pandemic Planning: Looking Beyond Seasonal Flu
WHO also updated its guidance for developing candidate vaccines for zoonotic influenza strains — those that originate in animals but can infect humans. These viruses pose potential pandemic threats, and WHO’s work in this area underscores the importance of maintaining readiness across all regions, including remote areas like Thunder Bay.
With public health still recovering from the impacts of COVID-19, ongoing flu surveillance and vaccine planning are essential. Thunder Bay’s medical community should stay alert to these global developments, as they shape public health strategy and vaccine procurement planning in Canada.
