Like other influenza viruses, equine influenza constantly changes so vaccine strains need to be updated periodically.
Information is collected from viruses from all over the world, which is used to recommend suitable strains for vaccines. As part of this process the AHT carries out surveillance in the UK, sponsored by the HBLB. An independent panel of experts, including AHT scientists, meet every year to select strains.
The official recommendations are approved by the World Organisation for Animal Health (OIE) and published annually in their second quarterly bulletin and are available on the OIE website (http://www.oie.int).
The current recommendations (2015) are that vaccines for the international market should contain both clade 1 and clade 2 viruses of the Florida sublineage:
Clade 1 is represented by A/eq/South Africa/04/2003-like or A/eq/Ohio/2003-like viruses.
Clade 2 is represented by A/eq/Richmond/1/2007-like viruses
The recommendations have not been changed since 2010. Two vaccines available in the UK contain a recommended Clade 1 strain, only one product contains a recommended Clade 2 strain.
UK vaccines and OIE recommendations
|Vaccine name||Conform to 1995 recommendations||Conform to 2004 recommendations||Conform to 2010 recommendations|