Horse Vaccines – What Does Your Horse Need?


You probably get a postcard from your horse’s vet twice a year, reminding you about spring and fall vaccinations for horses. But what horse vaccines are needed?


Table of contents:


Core vaccines

Risk-based vaccines

What to do after your horse is vaccinated

Vaccines and traveling with your horse

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Why are vaccinations an excellent idea for preventive horse care? 


  • Some equine diseases are deadly. Others are transmittable to humans (zoonotic diseases), and some leave lasting effects. All of them are expensive. Vaccinations prevent and lessen the severity of an equine disease infecting your horse.  


  • If you go to horse shows or travel with your horse, vaccinations help prevent the wildfire-like transmission of diseases through a population. Strangles and EHV-1 often make the news.  


giving vaccines to a gray horse

Protect your horse and the horses in your area with vaccines.


What vaccines does my horse need?


  • A core list of vaccines is outlined by the American Association of Equine Practitioners (AAEP). All horses need protection from these endemic, highly contagious, and sometimes zoonotic diseases.  The bonus benefit of these core vaccines is many years of practical and safe use. 


Core vaccines to protect your horse




Warm-blooded creatures transmit rabies, and while it’s rare in horses, it can infect humans. There is certain death with rabies, as the virus infects the brain and central nervous system. There is no cure, and it’s too late once signs of the disease appear.




A jerk of a bacteria, Clostridium tetani, causes tetanus in horses, humans, and other creatures. This bacteria causes severe muscle spasms and tightens the neck and jaw, hence the nickname “lockjaw.” The bacteria is transmitted via little cuts or breaks in the skin, usually from punctures or wounds from objects. Most horses will die from this disease or the necessary euthanasia.


West Nile Virus


We have the mosquito to blame for the transmission of this neurological disease. The virus is sometimes benign and doesn’t cause signs of sickness. Other times, it can create lethal neurological problems, like stumbling, inability to stand, hind limb weakness, inability to swallow, depression, and confusion.


Eastern and Western equine encephalitis (EEE and WEE)


The EEE and WEE encephalitis types are similar viruses that create neurological problems. Mosquitos, ticks, and other blood-suckers transmit these deadly viruses. 90% of horses with EEE and 50% with WEE do not survive.


For more on mosquito-related horse diseases, read this


vet truck

Your vet, not the internet, has the best plan for your horse’s health.


Risk-based vaccines


Your vet will give risk-based vaccines as needed, based on your horse’s lifestyle and location. Interestingly, some show organizations require some of these risk-based vaccinations before entering the showgrounds.    

Risk-based vaccines for horses include:




Botulism is another bacteria, Clostridium botulinum, that is deadly. It poses a risk for horses when food sources, like moldy round bales, harbor the bacteria. Moldy hay and under-fermented haylage are common culprits. Signs of toxicity appear about 24 hours after exposure, and death is likely. While there are treatments, a horse may never fully recover. 


Rhinopneumonitis (Equine herpesvirus)


This virus is similar to the common cold and is linked to EHV-1 outbreaks that sometimes close showgrounds. It’s highly contagious from horse to horse, or horse to person to horses. 


Equine influenza


This is the horse version of the flu, causing respiratory problems. It’s highly contagious and can spread from horse to horse, or with the help of people, grooming tools, shared buckets, etc. High fevers and complications make this horse flu dangerous but rarely lethal.  


Equine viral arteritis


This virus is of primary concern to pregnant mares, causing abortions. Stallions are often the primary transmission vehicle and, unfortunately, can carry the virus for a lifetime.


Potomac horse fever


Here we have another bacterial horse disease transmitted by insects, primarily aquatic bugs like the mayfly. Because insect vectors are more common in the summer, spring vaccination is the best time to protect your horse. 




Another bacterial disease causes “lepto” in horses, whose urine can contaminate the ground and water supply. Lepto can be transmitted to humans and causes depression, fever, moon blindness, and chronic eye inflammation in horses. 


Rotaviral diarrhea


This diarrhea-inducing virus attacks the intestinal lining of horses. It’s usually seen in foals with diarrhea, leading to dehydration and other problems. 


Snake venom


Some toxoid vaccines specifically help protect from some species of venomous snakes. When an animal receives a toxoid vaccine and is better, they still need anti-venom and other supportive care after a bite. When snake bites happen, the volume of venom injected is unknown and may overtake the protection of the toxoid vaccine.  


Read more about rattlesnakes and horses

Read more about copperheads and horses

Lyme’s disease


Ticks transmit Lyme disease in horses by hosting the offending bacteria. Antibodies to Lyme’s can be found in horses without clinical signs of disease, which include depression, underperformance, swollen eyes, and swollen legs. Some horses present with neurological problems like fever, loss of muscle mass, difficulty eating, and other neurological signs. Some vets will give horses the off-label use of the canine Lyme vaccine.

Tick control strategies can be found here



The upper respiratory system of the horse is the target of the strangles bacteria. Lots of swelling and sometimes open sores around the jowls and neck appear. This disease is highly contagious among horses. 


Gray horse getting a vaccine

Many vaccines are combos of protection – like the flu/rhino.  Less pokes!


After the vaccine


  • Rarely, a horse will immediately react to a vaccine, even if previous vaccinations don’t create a reaction.  Severe reactions need a vet’s attention within a few minutes.  Having your vet administer vaccines puts your vet on the farm should a severe reaction occur. 


  • Some horses may feel a bit under the weather after vaccines.  Checking your horse’s temperature and vital signs often for the first few days gives you an idea of how your horse is feeling. 


  • You may also find a lump or muscle soreness after vaccines are given.  If that’s the case, your horse may want an ice pack and a day off from exercise.


Vaccinations and traveling and showing with your horse


Coggin’s test


  • This test can be required for horses to participate in shows. Some barns require yearly testing, as well. You will need a Coggin’s certificate to travel between states with your horse.  


  • The Coggin’s test looks for Equine Infectious Anemia (EIA). This virus does not have a cure or a vaccine – prevention is the only option.  


  • Horseflies and other biting bugs transmit EIA. Horses in close proximity are at risk, and infected horses may show signs of fever, anemia, muscle and weight loss, organ damage, and eventually death.


Health certificate


  • The Certificate of Veterinarian Inspection (CVI) is necessary for horses to travel between states and sometimes within the state. A veterinarian must certify that your horse shows no signs of illness during the inspection.  


Flu/rhino vaccination


  • Some horse show organizations, like the USEF, require flu/rhino vaccinations every six months to be on the show grounds.  


  • The series of vaccines may differ when you have your horse vaccinated in the spring and fall. Some need a yearly booster; others need boosting every six months. Your vet can help you design a custom vaccine schedule for your horse to cover all risks. And don’t forget to give your horse lots of treats.   


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