2026 Flu Vaccine Recommendations: Southern Hemisphere Update
- The World Health Association (WHO) has released its recommendations for the composition of influenza vaccines for the 2026 southern hemisphere influenza season.
- The WHO recommends different compositions for egg-based and cell culture/recombinant protein/nucleic acid-based vaccines.
- The slight difference in the H3N2 component between egg-based and other vaccine types is a common practice, allowing manufacturers to optimize vaccine production based on their specific technology.
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WHO Announces 2026 Southern Hemisphere Influenza vaccine Recommendations
Published September 27, 2024, at 07:37 AM EDT. Updated as needed.
Key Takeaways: 2026 Influenza Vaccine Composition
The World Health Association (WHO) has released its recommendations for the composition of influenza vaccines for the 2026 southern hemisphere influenza season. These recommendations,formulated in consultation with the WHO influenza vaccine composition advisory committee and collaborating centers,guide the growth and production of vaccines by pharmaceutical manufacturers and regulatory bodies worldwide. A key change is the continued phasing out of the B/Yamagata lineage component in most vaccines.
Vaccine Composition Details
The WHO recommends different compositions for egg-based and cell culture/recombinant protein/nucleic acid-based vaccines. This distinction reflects differences in how these vaccines are produced and how well certain strains grow in different systems.
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 Culture-, Recombinant protein- 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 slight difference in the H3N2 component between egg-based and other vaccine types is a common practice, allowing manufacturers to optimize vaccine production based on their specific technology.
Phasing Out the B/Yamagata Lineage
For the fourth consecutive recommendation as September 2023, the WHO committee maintains that including a B/Yamagata lineage antigen is no longer necessary. WHO explains that circulating influenza B viruses have been predominantly of the B/Victoria lineage, making the Yamagata component redundant in providing broad protection.
Quadrivalent vaccines,which currently still include the B/Yamagata component,are expected to transition to trivalent formulations (containing only the H1N1,H3N2,and B/Victoria strains) over time. The WHO will no longer provide updated recommendations for the B/Yamagata lineage component.
Pandemic Preparedness: Zoonotic influenza
Beyond seasonal influenza,the WHO is also focusing on pandemic preparedness. The organization has updated its recommendations for developing new candidate vaccine viruses for