Commonground
Senior Moderator
23 – 26 February 2026
Istanbul, Türkiye WHO Consultation
Background
The periodic replacement of viruses contained in influenza vaccines is necessary to ensure vaccine effectiveness, given the continuous evolution of influenza viruses circulating and infecting humans.
Twice each year, WHO organizes consultations with an advisory group of experts to analyze influenza virus surveillance data generated by the WHO Global Influenza Surveillance and Response System (GISRS), and issues recommendations on the composition of the influenza vaccines for the following influenza season. These recommendations are used by the national vaccine regulatory agencies and the pharmaceutical companies to develop, produce and license influenza vaccines.
Objectives
Istanbul, Türkiye WHO Consultation
Background
The periodic replacement of viruses contained in influenza vaccines is necessary to ensure vaccine effectiveness, given the continuous evolution of influenza viruses circulating and infecting humans.
Twice each year, WHO organizes consultations with an advisory group of experts to analyze influenza virus surveillance data generated by the WHO Global Influenza Surveillance and Response System (GISRS), and issues recommendations on the composition of the influenza vaccines for the following influenza season. These recommendations are used by the national vaccine regulatory agencies and the pharmaceutical companies to develop, produce and license influenza vaccines.
Objectives
- Analyze the antigenic and genetic characteristics of seasonal influenza viruses circulating and infecting humans, taking into consideration the available epidemiological and clinical information from individual countries and regions;
- Make recommendations on the composition of influenza virus vaccines for use in the 2026-2027 northern hemisphere influenza season; and
- Review the antigenic and genetic characteristics of recent A(H5) and other subtypes or variant zoonotic influenza viruses, that the WHO Collaborating Centres of the GISRS received and the need to develop new candidate vaccine viruses for pandemic preparedness purposes.
- Representatives from WHO Collaborating Centres for influenza (CCs) of GISRS;
- Representatives from WHO Essential Regulatory Laboratories (ERLs) of GISRS;
- Representatives from National Influenza Centres and WHO H5 Reference Laboratories of GISRS;
- Representatives from the WHO Collaborating Centre for Modelling, Evolution, and Control of Emerging Infectious Diseases;
- Representatives from the FAO/WOAH Network of expertise on animal influenza (OFFLU); and
- Other invited subject matter experts
- Review of antigenic and genetic characterization data of seasonal, A(H5) and other subtypes or variant influenza viruses analysed by the WHO Collaborating Centres and other reference laboratories;
- Review of global influenza activity;
- Analysis of vaccine serological study results;
- Recommendations for the composition of influenza virus vaccines for use in the 2026-2027 northern hemisphere influenza season; and
- Review of the need and subsequent selection of new A(H5) and other subtypes or variant viruses for the development of new candidate vaccine viruses for pandemic preparedness purposes.