We recommend that all horses are vaccinated against equine influenza.
An initial primary course of two vaccinations must be given: the second vaccination must be administered within 21-60 days of the first vaccination.
The first booster must be administered within 6 calendar months following the date of the administration of the second vaccination of the primary course.
Note: individual horse owners are advised to follow their vets’ advice on the intervals recommended by the manufacturer for the specific product used (typically 4 or 4-6 weeks between the 1st and 2nd vaccine and 5 months between the 2nd and 3rd vaccine).
A minimally appropriate subsequent booster schedule can be considered. Booster vaccinations must be administered at a maximum of 12 months intervals. 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, we urge 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.