Introducing The 4 Way Horse Vaccine

Last Updated on April 4, 2022

In recent years, vaccines have hit the headlines, sometimes for all the wrong reasons. However, most of us get our horses vaccinated without querying what is in the vaccine. But what is the 4-way horse vaccine and is it the right one for your horse?

The choice of horse vaccinations can be overwhelming! It can be difficult to know which is the right vaccine for your horse. Let’s take a look at horse vaccinations and find out what they are all about!

What Is A Vaccine?

Vaccines, or vaccinations, are injections that are given to your horse to protect them from certain diseases. They must be given at specific times and at the correct intervals for them to work properly. You may sometimes hear of vaccinations referred to as inoculations.

Vaccinations work by introducing a tiny, harmless replica or fragment of a disease-causing pathogen into the body. This causes an immune reaction in your horse, which creates antibodies that can kill this pathogen. Then, when your horse is exposed to the disease in real life, it can kill the disease-causing pathogen before infection occurs.

In horses, there is a range of different vaccines available. Which ones are given to your horse will depend on many factors, including the age and location of the horse. Whether your horse is used for breeding is also a risk factor, and the cost of the vaccine can also affect which one is used.

What Diseases Can Horses Be Vaccinated Against?

The range of different diseases which horses can be inoculated against is huge! Equine vaccinations are available for all the following diseases:

  • Tetanus
  • Equine Influenza
  • Equine Herpes Virus
  • Botulism
  • Equine Viral Arteritis
  • Equine Encephalomyelitis (Eastern & Western)
  • Rotavirus
  • West Nile Virus
  • Rabies
  • Streptococcus Equi
  • Potomac Horse Fever

As with any type of medication, vaccinations should only be given when absolutely necessary. It would be bad practice to give your horse a vaccination against diseases to which it is unlikely to be exposed.

For instance, in the United Kingdom rabies cases are incredibly rare. Therefore, horses in the UK are not vaccinated against this disease unless they are traveling abroad.

The Horse Encyclopedia

What Is The 4 Way Vaccine For Horses?

So, let’s take a look at different types of vaccines for horses. The first of these is the 4-way horse vaccine, which is one that your veterinarian may recommend to you. This vaccine gives your horse protection against four different transmissible equine diseases.

However, confusingly there are different types of 4-way horse vaccines that protect against different diseases! So, it is very important to check with your veterinarian to discuss which one is right for your horse. They will know which diseases are most prevalent in your local area.

The 4-way horse vaccine may include any combination of four of the following transmissible diseases:

  • Equine Influenza
  • West Nile Virus
  • Tetanus
  • Eastern Equine Encephalomyelitis
  • Western Equine Encephalomyelitis

Most 4-way horse vaccines will contain the last three components, with either equine influenza or West Nile virus as the fourth disease.

Why Do Horses Need The 4 Way Horse Vaccine?

It is very important to get your horse vaccinated as it will protect your horse against some very dangerous diseases. Some of these, such as tetanus, can be transmitted through soil or rusty objects, so even a horse that lives alone should be vaccinated.

Other diseases, such as equine influenza, are highly contagious. This means that they are transmitted from horse to horse very easily. Vaccination of horses prevents the spread of these diseases through the horse population.

What Is A Vaccine

If your horse is fit and healthy, it is your responsibility to get it vaccinated. This helps to contribute to something called herd immunity.

This happens when enough horses are vaccinated to stop the spread of disease. This is essential to protect vulnerable horses such as foals and elderly equines.

Is The Equine 4 Way Vaccine The Right One For Your Horse?

Whether the 4-way vaccine is the right one for your horse is something that depends on your location and other factors. For example, if you want to attend competitions and other events, you may be required to show that your horse has been vaccinated against certain diseases.

It may be that a higher or lower risk of certain diseases in your geographical area will affect your choice of vaccine. Your local veterinary clinic will be able to advise you on the most suitable vaccine for your horse.

When Is The 5 Way Shot For Horses Used?

The 5-way horse vaccination protects against all the same diseases as the 4 way shot. It also includes protection against equine herpes virus. The 5-way horse vaccination is the one most commonly administered by equine veterinary practitioners.

When Is The 5 Way Shot For Horses Used

Which Horse Vaccinations Are Essential?

The core equine diseases that horses should be vaccinated against are tetanus, equine encephalomyelitis, and West Nile virus. All these diseases pose a threat to any horse, no matter what circumstances they live in.

Tetanus can be found in the soil and on rusty and grimy surfaces. This means that any horse can be infected with tetanus. Both equine encephalomyelitis and West Nile virus are transmitted to horses by mosquitoes.

The name of a vaccine simply tells you how many diseases are being vaccinated against. You need to know which diseases are being prevented, whether it is a 4-way, 5 way, or even a 6-way vaccine. Don’t assume that just because it covers a lot of diseases that it will protect your horse against the core ones!


So, as we have learned, a 4-way horse vaccine gives your horse immunity against four diseases. This will normally include eastern and western equine encephalomyelitis, tetanus, and either West Nile virus or equine influenza. This vaccination is not given as commonly as the 5-way horse vaccine, which also gives protection against equine herpes virus.

We would love to hear about your experiences with horse vaccinations. In your opinion, are they a good thing or a bad idea? Are you maybe thinking of buying a horse and have a few questions you’d like us to answer about vaccinations? Add a comment below this post and we’ll get back to you!

Can a horse recover from West Nile?

Although some horses do recover from West Nile virus (WNV) infection, they sometimes exhibit long-term neurological or behavioral abnormalities. Older horses are more likely to experience severe signs than younger horses. Horses who are severely affected by this disease may develop a chronic form of WNV encephalomyelitis (CFE) and require intensive medical care for many months or even years. Horses infected with West Nile virus may also be at risk for other infectious diseases, such as equine infectious anemia virus (EIAV). The latter virus is known to cause clinical signs in some horses with CFE.

When is the best time to vaccinate horses?

Horses are vaccinated annually at the beginning of the spring for a range of infectious diseases. They need to mount a robust immune response before they’re exposed to the disease causing pathogens. If your horse has not had the opportunity to mount an immune response and you vaccinate it during the summer when it’s hot and the horses are on pasture, there’s a good chance that the vaccine won’t be as effective. 

Can humans get equine influenza?

No, humans don’t get equine influenza from a horse. However, people can physically carry the virus on their skin, hair, clothing and shoes, and can therefore transfer the virus to other horses. If a person is caring for an infected horse or if that horse becomes ill after contact with someone else’s horse, the risk of human-to-horse transmission is even higher.
What are the symptoms of equine influenza? Equine influenza is an acute respiratory illness that usually affects the upper respiratory tract of horses. It can cause coughing, nasal discharge, fever, labored breathing and pneumonia.  

How long after injections can you ride a horse?

It’s recommended to stall rest horses for 24 hours after the vaccination and to not exercise/ ride the horse immediately after treatment as well as one day following treatment. In the mean time the horse should be observed for possible side effects of the vaccine. The vaccine is usually given by a veterinarian and you will be asked to sign a permission form (which will be provided to you) before the horse can be vaccinated. Please read carefully the directions on the vaccine and follow them carefully. If any questions arise, please contact your veterinarian or your local equine clinic. 

Can horses survive tetanus?

Tetanus is a life-threatening condition caused by anaerobic bacteria that can cause stiffening of the muscles and muscular spasms. It can be prevented by vaccination. Horses can get tetanus, and their mortality rate for this disease is as high as 80%. Tetanus spores are dangerous for humans, too. They can enter wounds and release a toxin that affects the nervous system.
Tetanus usually occurs after a penetrating wound or injury from something sharp, such as a nail or piece of wood. Spores are also found in soil, dust, and water. Horses need to be vaccinated before they enter a show or a training facility. This way, if a horse gets cut, the vaccine will prevent it from getting tetanus. The tetanus vaccine is safe for all ages and breeds of horses. It is given in a series of injections that must be spaced at least two weeks apart.