Equine Vaccinations

The following vaccinations are available for your horse in the UK:

Equine Flu

What does it do?

It causes symptoms similar to true flu (as opposed to ‘man flu’) in humans. The virus attacks the lining of the respiratory system and can make the horse very sick. Secondary complications can include pneumonia and even meningitis. Recovery can be prolonged.

Why should I vaccinate my horse if the disease is not currently in the UK?

Flu spreads very fast once it arrives in a country. If it does arrive in the UK, there may not be time to get your horse fully vaccinated before infection threatens. It takes a minimum of about 6 weeks to get an unvaccinated horse prepared: 2 initial injections 4 weeks apart and time for the immune response to develop. In addition, if Equine Flu arrived in the UK, you may find you are not the only one needing their horse vaccinated and your vet may be a little busy!

Equine Flu is a nasty disease and our greatest protection is in having a high percentage of the horse population protected by vaccination so that if it does arrive it is unable to spread as fast. You have a responsibility not just to your horse but also to the national horse herd to vaccinate your animal.

I have a foal – when do I start the vaccinations?

Vaccinations are generally started at 6 months. Before that the mare’s colostrum may interfere with the effectiveness of the vaccination.

What does the starter course entail?

Two injections 4 weeks apart, followed by a 3rd injection 5 months after the 2nd vaccination. Multiple vaccinations are required for 2 main reasons. Firstly, nearly all inactivated vaccines need one shot to ‘prime’ the immune system and then subsequent shots to develop a really strong antibody response. In addition, not all vaccines are as good at generating an immune response. Flu vaccines need extra doses to really provide a good response.

Will the vaccination definitely cover a new flu strain?

Possibly not. The situation is exactly the same with human flu. The scientists have to try and make predictions about which strains of flu may hit next and develop vaccines to combat those. There are 2 Types of Equine Flu and lots of strains. Type 1 (H7N7) and has not been seen for some time. Type 2 (H3N8) has European and American sub-strains. We use the Proteq Flu range which covers some of the newer strains out there.

What happens if the vaccination is overdue?

This can be confusing. Put simply, there are 3 sets of rules:


Tetanus doesn’t happen anymore does it?

Yes it does.

What does Tetanus do?

The bacteria normally start by colonising dead tissue in a wound. Incubation of the disease can be slow, up to 3 weeks. Eventually the bacteria release a toxin travels throughout the body and ‘locks’ all muscles in a terrible rigid state. The horse is completely conscious and aware of what is going on but unable to move and it cannot eat or drink because of lockjaw. It is an awful disease and a horrible way to die. Treatment is possible but it is intensive, expensive and there is no guarantee of success.

There is no justification for not vaccinating your horse against tetanus.

Equine Herpes Virus Strains 1 & 4

What do these viruses do?

There are 4 strains of the Equine Herpes Virus (EHV1, EHV2, EHV3 and EHV4). Vaccinations are unavailable for EHV2 (respiratory disease) and EHV3 (a sexually transmitted disease). Strains 1 & 4 primarily cause respiratory disease but EHV1 can also attack the nervous system causing hindleg paralysis. Importantly both EHV 1 and 4 can also cause abortions in pregnant mares. Anyone breeding should think carefully about protecting their mare against herpesvirus abortion.

How common are they?

The viruses are very similar to human cold sores (also a herpes virus). Once infected, the horse will never get rid of the virus although it may lie dormant for long periods. The latest data suggests that around 50% of adult horses have been infected with the EHV1 virus.

Equine Arteritis Virus

What does it do?

Primarily it damages the lining of small blood vessels causing oedema and damage to organs. Although it can be spread by aerosol, it is primarily a problem when an infected stallion is used for breeding. The virus is carried in semen and will go on to infect over 85% of the mares covered or inseminated. Although these mares will not abort the resultant foal if they do become pregnant, the infected mare will then spread the disease to the other horses around her. Infection of an already pregnant mare may well cause abortion.

Should I be concerned if I want to breed my mare?

This is an important disease and if it occurs it is a legal requirement to notify DEFRA who will then (hopefully) take action to limit the spread of the disease. The 2009 HBLB recommendations are that you should not vaccinate your mare. The emphasis is on preventing any infected stallions from breeding. Responsible stallion owners will blood test their stallions to ensure they have never been exposed to the virus – that they are ‘seronegative’.

Equine Rotavirus

What does it do?

This virus causes diarrhoea in foals less than 2 months old. If severe, this can be life threatening.

What does the vaccine do?

The vaccine is given to the pregnant mare in the 8th, 9th and 10th month of pregnancy. The aim is to boost the levels of anti-rotavirus antibodies in the mare’s colostrum. These antibodies are then passed onto the foal and protect the foal from the virus. Obviously, it is crucial that the foal gets a good intake of colostrum otherwise the vaccine is ineffective.

Should I use it?

Rotavirus diarrhoea is most common on stud farms with large numbers of foals. The risk is low if you have one mare and wish to put her in foal. If you breed regularly it is worth investigating any diarrhoea outbreaks. If this shows up rotavirus, it will give you warning that you need to vaccinate the following year.