Is Your Horse Truly Protected?

Following the recent EHV (Equine Herpesvirus) outbreak, staying current on booster vaccines, especially for horses that travel or are exposed to others, is critical for reducing disease spread and protecting your horse's health.

While immunostimulants can offer support during high-risk periods, they are not a replacement for timely vaccinations, which should always remain the top priority.

To help horse owners navigate these concerns, Dr. Laura Meier, Technical Service Veterinarian at Valley Vet Supply, shares her insight on the importance of vaccinations and keeping up with booster doses.

Why Keep Horses Vaccinated Year-Round?

Veterinarians recommend core vaccines annually because the diseases they protect against carry a high level of risk. These diseases are often highly fatal, highly contagious, or both.

"Scientific data and research support why the American Association of Equine Practitioners (AAEP) deems these vaccines so important to administer regularly," Dr. Meier says. "We unfortunately do not know when an outbreak will occur, so it is best to help prevent it versus trying to vaccinate after an outbreak has occurred."

When a horse receives a vaccine for the first time, the initial dose introduces the antigen to the immune system and triggers only a small response with little to no immune memory. The second dose produces a stronger response and establishes the memory needed for long-lasting protection.

Protection does not last indefinitely, which is why following the label's booster recommendations, every six months, annually, or every three years depending on the vaccine, is essential.

How Do Vaccine Plans Differ for High-Risk Horses?

Vaccine recommendations vary according to a horse's lifestyle and the transmission methods of each disease.

Diseases like rabies, which spread through contact with infected animals, pose a risk to all horses. Diseases that mosquitoes or other blood-feeding insects transmit, such as the sleeping sicknesses (EEE, WEE) and West Nile Virus (WNV), concern people wherever these insects exist, regardless of whether a horse travels or stays at home.

Respiratory diseases such as EHV, EIV, and Strangles spread through nasal secretions or airborne droplets. Horses that travel, compete, board, or come into contact with horses that have been around others face a higher risk of exposure compared to horses that never leave the pasture or encounter new horses.

"The important thing to do is to make sure you look at the big picture," Dr. Meier says. "I hear quite often, 'We don't go around other horses often, so we shouldn't need to worry about those diseases.' All it takes is one time."

The goal is to ensure immunity is highest when risk is highest.

Most EIV vaccines provide immunity for about six months. Veterinarians often recommend boosting Flu/Rhino every six months for horses at higher risk - those that travel, board, compete, or commingle.

Do Missed Boosters Put Horses at Risk?

If someone does not give the initial booster within the recommended 2-6 week window, the immune system will not develop proper memory.

"Without that memory, the vaccine cannot provide protection, leaving the horse at risk for severe illness or even death if exposed to the disease," Dr. Meier explains.

After the first vaccine series completes correctly, immune memory lasts for a period of time but gradually fades. A booster restores that protection and helps maintain the appropriate antibody levels in that animal which is why you must follow the booster schedule that is on the label. These guidelines rely on research that shows how long protection lasts and when to strengthen immunity again.

How Can Owners Reduce Disease Spread?

"Have biosecurity protocols made and actually use them," Dr. Meier says. "It is easy to 'let it slide just this once,' but by nature, we tend to let things slide more than once if we allow it one time."

Effective Biosecurity Practices Include:

Limit contact and use separate equipment.

Remove organic material before disinfection.

Practice good personal hygiene.

Quarantine returning or new horses for at least 21 days.

Monitor exposed horses closely.

How Can Owners Learn From Outbreaks?

"Prevention is key," Dr. Meier says. "Stay ahead of the game. Implement a strategy that reminds you to give vaccines at their appropriate times. Take the extra step to protect your companion."

Whether it's a reminder on your phone or a large calendar in the tack room, keeping track of vaccination dates is essential to maintaining your horse's health.

Staying proactive with vaccinations, boosters, and biosecurity gives horses the strongest protection possible, before an outbreak occurs.

Learn more about how boosters strengthen immunity in The Importance of the Booster Dose.