Infectious Diseases

BEVA strongly recommends that all horses should be vaccinated for Tetanus following manufacturers’ recommendations for primary course and boosters which vary depending on the product chosen.

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.

We recommend that the groups of horses listed below are vaccinated with a primary course (2 vaccines) and thereafter vaccination should continue as follows:

Non-pregnant females and males

Re-vaccinate against EHV-1 at 6-month intervals. This protocol is recommended for

• Horses > 6 months and less than 5 years of age
• Horses that may come into contact with pregnant mares.
• Horses housed at facilities with frequent movement of horses on and off the premises.
• Horses which frequently attend gatherings where horses mingle in close proximity.

Pregnant mares

Re-vaccinate against EHV-1 at 6-month intervals and in addition give vaccines at 5, 7 and 9 months of gestation.

Vaccines for EHV 1 and 4 can be given at the same time as those for equine influenza and tetanus. There is no clear evidence of harm or benefit associated with combining EHV vaccines with other vaccines. Presently available vaccines reduce clinical signs due to infection with EHV1 and 4 and reduce abortion caused by EHV1 infection. Currently there is not clear evidence of benefit or harm when used in populations exposed to high risk of neurological EHV.

In the UK, vaccination is currently permissible and a licensed product is available. We recommend that horses travelling to areas where there is a risk of West Nile Fever (for example during the mosquito season in a country where the virus is endemic) should be vaccinated before they travel. Regular vaccination is particularly relevant to race and sports horses travelling abroad for competition. For up-to-date information on global distribution go to the International Collating Centre for equine disease. Manufacturers’ recommendations for dosing and administration should be followed. There is no clear evidence of harm or benefit associated with combining West Nile vaccine with other vaccines.

We support the guidance provided in HBLB’s International Codes of Practice for Breeders, 2022 which emphasises the importance of routine vaccination against EVA for stallions and teasers resident in the UK. Detailed guidance on recommendations for reducing the risk of EVA stallions imported for breeding and sport and when semen is used for artificial insemination.

Vaccines aimed to reduce risk of clinical signs associated with Strep equi subspecies equi infection are available with published experimental data to support their efficacy and safety. We will continue to appraise future research publications and experience from clinical practice before adopting a position on these vaccines.