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Vaccinations are an important part of preventative medicine for all horses. Additionally many equestrian sports governing bodies (including BHA, FEI, BE) require up-to-date vaccination records to enable horses to compete under their rules.


Every horse should be vaccinated against tetanus. Horses are particularly susceptible to tetanus infection which usually proves fatal. Tetanus is caused by a potent neurotoxin produced by the bacteria Clostridium tetani. Clinical signs usually develop 2-3 weeks after infection; they start as a generalised stiffness and progress through focal muscle spasms to violent spasms involving the whole body. The organism is present in the soil and in faeces. Iinfection occurs via open, surgical or puncture wounds or through exposed tissue (i.e. umbilicus of foal or retained placental membranes in broodmares).

Tetanus is not a contagious disease. Vaccination against tetanus is highly effective in preventing the occurrence of the disease. Tetanus is often given as a combined vaccine with influenza but can be given on its own.

  • Primary course: Two vaccinations 4-6 weeks apart
  • Initial booster: 12 months after the second primary vaccination
  • Subsequent boosters: Every 2 years

Broodmares should receive a tetanus booster vaccination 4-6 weeks prior to foaling to ensure high colostral antibody levels.

Foals should ideally receive tetanus antitoxin as part of a post-foaling check shortly after birth to supplement protection from colostral antibodies. Foals can begin their primary vaccination course from 5 months of age.


Equine influenza is an extremely infectious viral disease which spreads rapidly between horses via respiratory droplets or from objects that have come into contact with infected particles. Any horse that comes into contact with others should be vaccinated against influenza.

Clinical signs of infection vary according to vaccination and health status of the horse but can include a raised temperature (39-41°C), dry cough and watery nasal discharge (which may become thicker if secondary infections occur) as well an inappetance, depression and stiffness. Horses usually clear the infection in a couple of weeks but require a significantly longer convalescent period. In sick, old or young animals equine influenza can be fatal.

The specific requirements for vaccination differ between equine sport governing bodies. We recommend following the BHA rules (which most organisations including BE, BD, Pony Club etc conform to) unless you are competing under FEI rules.

Records of influenza vaccinations must be documented in the horse’s passport with each entry signed by the veterinary surgeon who gave the vaccine in order to comply with the rules of the governing bodies. Influenza is often combined with tetanus in a single injection.

BHA Rules

  • Primary course: Two vaccinations 21-92 days apart
    For optimum immunity we recommend a 4-6 weeks gap between these initial two vaccinations
  • Initial booster: 150-215 days after the second primary vaccination. This equates to approx. 5-7 months
  • Subsequent boosters: Within 1 calendar year of the date of the previous booster

No vaccination may have been given within 7 days of racing/competition/arrival at competition stables

FEI Rules

  • Primary course: Two vaccinations 21-92 days apart
  • Initial booster: Within 7 calendar months of the second primary vaccination
  • Subsequent boosters: Within 365 days of the date of the previous booster
  • Additionally: Horses must have received a booster within 6 calendar months + 21 days of arrival at the FEI event

Equine Herpes

Equine herpes is a ubiquitous horse virus. The majority of horses will have been exposed to herpes by the time they are two years of age.

The two most common strains are EHV-1, which causes respiratory disease (most commonly in foals and weanlings, often in the autumn and winter), neurological disease and abortion (often ‘abortion storms’), and EHV-4 which causes respiratory disease and very occasionally individual abortions. The majority of horses contract the disease and shed the virus showing only mild or no clinical signs. Transmission is by respiratory droplets of from aborted tissues or from objects that have come into contact with infected matter.

Immunity following infection is short-lived with the virus often establishing a latent infection. Vaccination is possible but again immunity from vaccination is short-lived with frequent boosters required to maintain immunity. None of the current vaccines offer protection against the neurological form of the disease.

Adult non-breeding horses

Due to the short-lived immunity resulting from vaccination and the mild (if any) clinical signs associated with respiratory disease in adult horses routine vaccination is rarely indicated. Exceptions to this include:

  • Horses under 5 years of age (especially those in training/competition)
  • Horse exposed to youngstock or broodmares (i.e. on studs)
  • Race/high-performance horses (EHV has been suggested as contributing to underperformance. These horses are also at an increased risk of exposure due to mixing at competitions and may be suffering from exercise-induced immunosuppression)

Where vaccination is indicated we recommend the following vaccination schedule:

  • Primary course: Two vaccinations 4-6 weeks apart
  • Subsequent boosters: Every 3 months


EHV can cause epidemic abortion or the birth of weak, nonviable foals. Abortion typically occurs weeks to months after exposure to the virus – for this reason there is little virtue in commencing vaccination in the face of an abortion storm. Vaccination does not guarantee immunity but does reduce the risk of abortion.

  • Vaccinations: 5, 7 and 9 months of gestation
    In high-risk situations it may be advisable to give an earlier vaccination at 3 months of gestation