Equine Influenza is a viral respiratory disease that is highly contagious to susceptible horses. Outbreaks of the disease are occurring with increased frequency worldwide despite the widespread use of vaccines. The highly contagious nature of equine influenza means that it has the potential to seriously compromise international movement of horses. For a number of years the FEI rules have required an annual booster vaccination, but recent research indicates that, for many vaccines protection declines after a few months. This means that towards the end of the vaccination year, horses may become susceptible to infection again, but may not show clinical signs of disease. These cases are particularly dangerous as they can spread virus and could initiate a serious outbreak of disease.

As a consequence of the risks involved, the FEI Bureau and General Assembly have approved a rule-change requiring all horses competing in FEI competition to be vaccinated every six months. This rule will be reviewed annually by the FEI Veterinary Committee and can be altered if the vaccination or disease situation changes.

Rule Change Approved by the General Assembly 2004
The FEI requirement for equine influenza vaccination will be for booster vaccinations at six-month intervals as from January 1, 2005.

Implementation of the Rule Change
1. Primary course of vaccination - a primary course should always be given according to the manufacturer’s instructions by injection or intranasal administration. This requires two doses of vaccine administered between a minimum of 21 to a maximum of 92 days apart (one to three months). The first booster vaccination must be given no more than six months +21 days (see item 5) after the second vaccination of the primary course; a shorter vaccination interval is obviously permitted.
2. Route of administration – the vaccine should be administered according to the manufacturer’s instructions (i.e. intramuscular injection or intranasal). The FEI will accept intranasal vaccines for both primary and booster doses. However, it is not possible to change the route of administration between the first and second vaccination of the primary course.
3. Specification of Vaccine – all proprietary equine influenza vaccines are acceptable to the FEI irrespective of the route of administration. Univalent vaccines are to be preferred over combination vaccines, especially with regard to vaccination against tetanus.
4. Details of Administration – vaccines must be administered by a veterinarian and the details of the vaccine, serial/batch number, the date and route of administration must be recorded in the FEI passport.
5. Booster vaccinations must be given at six-month intervals. However, to avoid interruption of the horses’ competition schedule, it is permissible to extend the six-month booster date by a maximum of 21 days. This provides a 3-week window after the six-month date to vaccinate the horse. (For example, a horse vaccinated on March 18, has a window for the next vaccination from Sept. 18-Oct 9). A shorter vaccination interval is obviously permitted.
6. The entering of vaccination details in new FEI passports/recognition cards or duplicates – if the vaccination history of a horse is very long, the veterinarian who has filled in the descriptive page of the passport/recognition card may use a specific statement to certify that the vaccinations have been administered in accordance with FEI regulations (for the exact wording see veterinary regulations, Annex II.I.11). Please note that until December 31, 2004, annual booster vaccinations were permitted and from January 1, 2005, bi-annual boosters are required.
7. Change in the vaccination schedule - When the vaccination schedule is changed from annual to bi-annual, the horse does not need a new primary