BEVA recommends that all horses are vaccinated against equine influenza as follows: 

Primary schedule

• V1 (initial vaccination)
• V2 (second vaccination): should be administered 21-60 days after V1
• V3 (first booster): should be administered 120-180 days after V2

Note: Individual horse owners are advised to follow their vet's advice on the intervals recommended by the manufacturer for the specific product used. The above V1 - V2 - V3 protocol satisfies both FEI and BHA requirements and is in line with the manufacturers’ recommendations (typically 4 or 4-6 weeks between V1 - V2, and 5 months between V2 - V3).

Subsequent booster schedule 

The minimally appropriate interval for a booster vaccination is a maximum of 12 months. However, we strongly endorse an optimal schedule achieved by increasing the frequency of boosters to within 6 months.

In deciding whether to follow the 'minimally appropriate' or 'optimal' vaccine schedules outlined above, BEVA urges horse owners and their vets to consider the following points:

• The primary aim of flu vaccination policies is to protect individual horses from clinical illness should they encounter equine influenza virus.
• There is considerable scientific evidence to support the assertion that horses which are vaccinated at six monthly intervals are protected more effectively from clinical signs of flu than those vaccinated at 12 monthly intervals, and are less likely to transmit infection.
• Additional benefit can be gained by administering boosters strategically, i.e. at the times of year corresponding with periods of increased horse gathering and consequent increased risk.
• Influenza virus spreads via the airborne route and has the ability to spread rapidly over distances in excess of those found on a typical equestrian premises, whether indoor or outdoor. Farm-to-farm airborne spread is possible in many regions of UK.
• The response to vaccination is not immediate and there must be an interval of at least 7 days between the most recent vaccine dose and mixing with other horses to have some benefit from that recent vaccine. This is a particularly important point to consider when introducing a recently vaccinated new animal to a property.

Science advances, "label claims" rarely do. We have the freedom to recommend the use of products “off label” or to use unregistered products where it is appropriate to do so in accordance with the veterinary cascade. This also extends to our use of vaccinations in practice. Our responsibility is to act in the best interests of the horses under our care and the evidence is unequivocal that in higher risk populations better protection is afforded by vaccination at 6 monthly intervals rather than 12.