Merck Animal Health Vaccines
The Science of Protected

From the breeding barn to the show ring and everything in between, we have the vaccines you need to protect your horse.

Now that's protected.

Prestige Vaccines

The Science of Significance

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Intramuscular Vaccines

Intranasal Vaccines

Vaccine Story

  • Antigen Purification System: A vaccine can never be too safe. Our technology, known as the Antigen Purification System, has been utilized for more than 20 years to help remove extraneous protein and cellular debris. Using this method of filtration purification allows concentration of antigen while minimizing adverse reactions. By purifying the vaccines using the APS, we reduce the debris that can cause undesirable injection site reactions in the horse.
  • Exclusive Havlogen® Adjuvant: Our killed vaccines are highly efficacious in part because of our exclusive Havlogen adjuvant. Havlogen stimulates the immune system to produce high, long-lasting levels of protection through the slow release of antigen. Due to the composition of Havlogen, the vaccine maintains suspension and does not settle to the bottom of the vial — resulting in consistency and potency in every dose. By combining our APS system and Havlogen adjuvant, we are able to produce a line of killed virus vaccines that are highly efficacious and have an exceptional safety profile. The filtration technology used in manufacturing Havlogen is so advanced that it has been shown to be 98% reaction-free in field safety trials.
  • Vaccine Guarantee: We stand behind our products. That's why we prove our commitment to the equine veterinarian, to the horse owner and, most of all, to the horse. Merck Animal Health will reimburse reasonable diagnostic and treatment costs, up to $5,500, for any horse properly vaccinated by a licensed veterinarian with one of our equine vaccines that contracts influenza, rabies, tetanus, West Nile virus, eastern, western or Venezuelan encephalomyelitis.

Get Vaccinating Right

Properly administered vaccines represent the most economical tools available to help prevent infectious diseases. Illness can take an enormous toll on your horse's well-being and performance and may jeopardize its life. To find more information on vaccinating and the diseases we can help prevent, please visit

Vaccine Chart