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Home > General > Influenza Outbreaks in Vaccinated Horses: Epidemiological Overview

Influenza Outbreaks in Vaccinated Horses: Epidemiological Overview

male veterinarian giving vaccine to a horse

Influenza outbreaks in horses are very serious, and it’s one of the biggest dangers facing horse owners. Equine influenza is highly contagious so getting your horse vaccinated is essential to its health. One of the questions we get most frequently is if vaccinated horses can catch the harmful disease. Unfortunately, the short answer is yes. They can. However, keep reading while we look at what the vaccination does and what happens if a vaccinated horse catches the flu so you can be better informed.

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Do Vaccinated Horses Catch the Flu?

Unfortunately, vaccinated horses can still catch the flu, but it’s much less likely, and the effects of the virus should be much less severe. Your horse is also more likely to return to health sooner than an unvaccinated horse.

Female vet checking horse teeth
Image Credit: wavebreakmedia, Shutterstock

What Is Equine Influenza?

Equine influenza is a respiratory disease that affects horses. It spreads quickly, and horses can start showing symptoms in only a few days. Two subspecies of the Influenza A virus are responsible, and they are related to but different from the influenza virus that affects humans. It targets the respiratory system and damages the mucous membranes

How Do Horse Catch Equine Influenza?

Horses catch equine influenza from other horses, and it’s extremely common in horses 2–3 years of age. Racetracks are hotspots for the disease because the horses come from all over, and many of them might be sick without showing any symptoms. Coughing, sneezing, and even breathing are all it takes to infect the other horses.

What Are the Symptoms of Equine Influenza?

The primary symptom of equine influenza is a deep cough, which will also help spread the disease. Some horses can suffer from muscle pain and be reluctant to move, and they might have enlarged lymph nodes. Anorexia is not uncommon, and some owners have witnessed signs of depression in sick horses.

Veterinarian examining horse leg tendons. Selective focus on hoof
Image Credit: Brastock, Shutterstock

What Is the Best Treatment for Equine Influenza?

Unfortunately, there is currently no treatment for equine influenza, and the best way to protect your horse is to get it vaccinated. Vaccinations make it less likely that your horse will catch it, and even if it does, it will likely suffer much milder symptoms, and recovery will be faster. The vaccine wears off quickly, and you will need to get a booster every six months to keep your horse healthy, especially if you visit the track or allow your horse around others that visit the track.

Will My Horse Suffer Permanent Damage from Equine Influenza?

Luckily, most horses will not suffer any permanent damage from equine influenza, but it can take a toll on their overall health if it’s chronic. The flu causes the horse to be less active, leading to muscle atrophy, a significant problem for track horses. It can also lead to weight gain and other serious health issues. Horses recovering from equine influenza are also susceptible to secondary infections due to the compromised immune horse shoe divider


We highly recommend getting your pet vaccinated frequently to help keep your horse healthy. If your horse gets closer than 150 feet to any horse that visits the track or even shares the same facilities, a vaccination every six months is the best protection. Check your horses regularly and listen for the telltale cough that is frequently one of the first signs your horse is sick.

We hope you have enjoyed reading over this short guide and found the answers you needed. If we have convinced you to get vaccinated, please share our look into influenza outbreaks in vaccinated horses and what you need to know on Facebook and Twitter.

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