WHO announces recommended 2023-24 flu vaccines for northern hemisphere

The World Health Organization (WHO) has announced the recommended viral composition of influenza vaccines for the 2023-24 influenza season in the northern hemisphere.

National vaccine regulatory agencies and pharmaceutical companies will now use this guidance to develop, produce and license influenza vaccines for the following season.

WHO organises consultations with an advisory group of experts twice a year to analyse influenza virus surveillance data generated by the WHO Global Influenza Surveillance and Response System (GISRS). The organisation then issues recommendations on the composition of the influenza vaccines for the following influenza season.

The agency’s recommendations are based on the advice from a group of experts from WHO Collaborating Centres (CC) and WHO Essential Regulatory Laboratories that analyse virus surveillance data generated by a global network of over 150 laboratories in 127 countries, areas or territories.

The objectives are to:

• Analyse the antigenic and genetic characteristics of the seasonal influenza viruses that are circulating, 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 2023-2024 northern hemisphere influenza season
• Review the antigenic and genetic characteristics of recent A(H7N9) and A(H5) viruses that the WHO Collaborating Centres of the GISRS received and the need to develop new A(H7N9) and A(H5) candidate vaccine viruses for pandemic preparedness purposes
• Review the antigenic and genetic characteristics of other recent subtype or variant influenza and the need to develop new candidate vaccine viruses for pandemic preparedness purposes.

Seasonal influenza is an acute respiratory infection caused by influenza viruses that circulate in all parts of the world.

Most people recover from fever and other symptoms within a week without requiring medical attention, but influenza can cause severe illness among high-risk groups such as the very young, the elderly, pregnant women, health workers and those with serious medical conditions.

WHO cites influenza vaccination as the current principal means of reducing or counteracting influenza mortality and morbidity burden, but the constantly evolving nature of influenza viruses requires continuous global monitoring and frequent reformulation of vaccines.