Twice each year influenza experts gather to discuss recent developments in human and animal influenza viruses around the world, and to decide on the composition of the next influenza season’s flu vaccine.
Due to the time it takes to manufacture and distribute a vaccine, decisions on which strains to include must be made six months in advance, Which means the composition of next fall's northern hemisphere’s vaccine must be decided upon in February.
NIAID has a terrific 3-minute video that shows how influenza viruses drift over time, and why the flu shot must be frequently updated, which you can view at this link.
This week the World Health Organization brought together representatives from GISRS (Global Influenza Surveillance and Response System), along with members of OFFLU (the OIE/FAO Network on Animal Influenza), and other experts to recommend what flu strains to include in next fall's vaccine.
- Despite scattered reports out of Eastern Europe this winter of a handful of `low-reactor' H1N1 viruses, the majority of H1N1 viruses around the world continue to be antigenically similar to the original A/California/7/2009-like strain, and so that will remain unchanged.
- The H3N2 component - a `problem child' for vaccine producers the past few years - is changed once again, this time to an A/Hong Kong/4801/2014 (H3N2)-like virus, the same as specified for the upcoming Southern Hemisphere's flu season.
- And the primary B component is switched to a B/Brisbane/60/2008-like virus, which also matches this year's Southern Hemisphere vaccine. The secondary B (for use in a quadrivalent vaccine) is a swap with last year's primary, and becomes a B/Phuket/3073/2013-like virus.
The WHO announcement, and link to the full report follow.
Recommended composition of influenza virus vaccines for use in the 2016-2017 northern hemisphere influenza season
25 February 2016It is recommended that trivalent vaccines for use in the 2016-2017 influenza season (northern hemisphere winter) contain the following:
It is recommended that quadrivalent vaccines containing two influenza B viruses contain the above three viruses and a B/Phuket/3073/2013-like virus
- an A/California/7/2009 (H1N1)pdm09-like virus;
- an A/Hong Kong/4801/2014 (H3N2)-like virus;
- a B/Brisbane/60/2008-like virus.
For more information