The best way to avoid getting the flu is to get the flu vaccine every year, before influenza season begins, although getting vaccinated at any time during the influenza season can still help prevent flu infections.
Getting the flu shot is especially important for those most at risk: pregnant women, children younger than 5 years, people older than 65 years, people with chronic medical conditions, such as HIV/AIDS, asthma, heart and lung diseases and diabetes, and people with increased risk of exposure to influenza, which includes health care workers.
Influenza viruses evolve constantly. Twice a year WHO makes recommendations to update the vaccine compositions in an effort to match the most common virus types circulating in humans at that time.
WHO Consultation on the Composition of Influenza Virus Vaccines for Use in the 2017-2018 Northern Hemisphere Influenza Season
27 February – 1 March 2017, Geneva, Switzerland
Background
The periodic replacement of viruses contained in influenza vaccines is necessary in order for the vaccines to be effective due to the constant evolving nature of influenza viruses, including those circulating and infecting humans.
Twice annually, WHO organizes consultations with an advisory group of experts to analyse 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
Analyse 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 the influenza vaccines for use in the 2017-2018 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; and
Review the antigenic and genetic characteristics of other subtype or variant influenza viruses infecting humans recently, and the need to develop new candidate vaccine viruses for pandemic preparedness purposes.
Participants (by invitation)
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; and
Representatives from the OIE/FAO Network of expertise on animal influenza (OFFLU).
Provisional main agenda items
Review of antigenic and genetic characterization data of seasonal, A(H7N9), A(H5) and other subtypes or variant influenza viruses analysed by CCs and other reference laboratories;
Review of the global influenza activity;
Analysis of results of vaccine serological studies;
Recommendations for influenza vaccine composition for use in the 2017-2018 northern hemisphere influenza season;
Review of the need and subsequent selection of new A(H7N9), A(H5) and other subtype or variant viruses for the development of new candidate vaccine viruses for pandemic preparedness purposes.