Merck Animal Health Introduces Updated Equine Influenza Vaccines

New equine influenza vaccines feature the most current clade 1 and clade 2 influenza strains.

Merck’s array of Prestige FluVac vaccines undefined

Merck Animal Health announces the availability of the next generation of influenza-containing vaccines for horses. Available in the PRESTIGE line of vaccines, the new influenza strains represent the most current equine influenza protection available.

“For the past 10 years, we’ve been monitoring influenza, along with other common infectious upper respiratory diseases, through the Merck Animal Health Biosurveillance Program—a partnership with the University of California, Davis. It was through this program that we identified and isolated a new, highly infectious and relevant equine influenza strain from the 2013 Ocala, Florida, influenza outbreak that impacted a large number of horses from all over the world,” said D. Craig Barnett, director of equine veterinary professional services, Merck Animal Health. “This strain is now part of our updated line of influenza-containing killed virus vaccines and represents a current, clinically significant strain responsible for a large influenza outbreak in well-vaccinated horses.”

The PRESTIGE line of influenza-containing vaccines includes Florida ‘13 of the clade 1 family and Richmond ‘07 of the clade 2 family, meeting current World Organisation for Animal Health (OIE) and American Association of Equine Practitioners (AAEP) guidelines for clade 1 and clade 2 strains. The clade 1 family of equine influenza primarily circulates in the United States, while clade 2 predominantly circulates in Europe.

“Due to the evolutionary changes that occur with equine influenza, known as antigenic drift, influenza-containing vaccines must be updated periodically to ensure protection against current strains of influenza circulating in the field and impacting our horses,” said Barnett. “And while we have not had any outbreaks of clade 2 in the United States to date, U.S. horses competing internationally should have clade 2 protection on board.”

Equine influenza is an important endemic disease concern and one of the most common causes of equine viral respiratory tract disease. It has been the culprit of some of the largest equine infectious respiratory disease outbreaks worldwide, disrupting major equestrian events and causing significant economic losses.1,2 Once the virus begins to circulate, it’s very difficult to control and can spread rapidly. Recovery can take several weeks to months.

Influenza vaccination is recommended at six-month intervals for any performance, show, or pleasure horses constantly at risk of exposure, including resident horses exposed to traveling horses.3 United States Equestrian Federation (USEF) and Federation Equestre Internationale (FEI)-sanctioned events both have six-month influenza vaccination requirements.

“A cornerstone of the Merck Animal Health Biosurveillance Program is identifying and monitoring current circulating strains of major equine respiratory pathogens such as influenza,” said Barnett. “This launch is a testament to our commitment to the science of healthier animals and we’ll continue to work to identify threats and deliver advanced vaccine solutions to help improve the lives of horses.”

The PRESTIGE line of vaccines features the proprietary Havlogen adjuvant and Antigen Purification System, formulated to maximize protection and minimize adverse reactions. The updated line of influenza-containing killed virus vaccines complements a robust Merck Animal Health influenza portfolio, headlined by the modified-live intranasal influenza vaccine, FLU AVERT I.N.

Perform with PRESTIGE Sweepstakes Announced

To educate horse owners on the risks of equine influenza and the importance of working with their veterinarian to design a vaccination program, Merck Animal Health recently introduced the “Perform with PRESTIGE” online sweepstakes. Now through June 30, 2018, horse owners can visit for a chance to win a Featherlite horse trailer, a trip to the 2018 World Equestrian Games in North Carolina, as well as many other monthly and weekly prizes. No purchase is necessary to enter or win, please visit for full sweepstakes rules.

For more information on the updated line of PRESTIGE vaccines, visit, or call 800-521-5767.


1. Daly, J.M.;MacRae, S.; Newton, J.R.; Wattrang, E.; Elton, D.M. Equine influenza: a review of an unpredictable virus. Vet. J. 2011;189:7–14.

2. Timoney, P.J. Factors influencing the international spread of equine diseases. Vet. Clin. North Am. Equine Pract. 2000;16:537–551.

3. American Association of Equine Practitioners (AAEP) Risk-Based Vaccination Guidelines (

For more than a century, Merck, a leading global biopharmaceutical company, has been inventing for life, bringing forward medicines and vaccines for many of the world’s most challenging diseases. Merck Animal Health, known as MSD Animal Health outside the United States and Canada, is the global animal health business unit of Merck. Through its commitment to the Science of Healthier Animals™, Merck Animal Health offers veterinarians, farmers, pet owners and governments one of the widest range of veterinary pharmaceuticals, vaccines and health management solutions and services. Merck Animal Health is dedicated to preserving and improving the health, well-being and performance of animals. It invests extensively in dynamic and comprehensive R&D resources and a modern, global supply chain. Merck Animal Health is present in more than 50 countries, while its products are available in some 150 markets. For more information, visit or connect with us on LinkedIn, Facebook and Twitter at @MerckAH. 

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