Horses Vaccinated with WEST NILE-INNOVATOR® and FLUVAC INNOVATOR® Generated Four Times the Immune Response to West Nile Virus

According to research, big one-shot combination vaccines may deliver a lower immune response than expected. While equine vaccine combinations that include West Nile virus and equine influenza/equine herpesvirus (rhino) antigens in a single formulation may be convenient, the horse’s immunity could be sacrificed. A study showed that separate administration of WEST NILE-INNOVATOR® and FLUVAC INNOVATOR® generated four times the immune response to West Nile virus than was produced by a big one-shot combination vaccine.1

westnile3 imageThe study compared serological responses to West Nile virus in 280 horses following six difference vaccine regimens. Vaccination regimens that combined West Nile virus with Eastern and Western equine encephalomyelitis (EEE/WEE) viruses and tetanus antigens in a single formulation appeared to impact the West Nile virus antibody response compared to vaccination regimens that employed concurrent administration of the West Nile virus component and the EEE virus, WEE virus and tetanus antigens.1

“Dividing antigens into concurrent, separate injections may help increase the horse’s immune response to West Nile.” said Kevin Hankins, DVM, senior veterinarian, Equine Technical Services, Zoetis. “While big one-shot combination vaccines may offer convenience, when developing vaccine programs for West Nile virus protection, veterinarians and horse owners should consider the implications of lower West Nile virus antibody responses in horses vaccinated with a West Nile virus combination vaccine. Though combination vaccines may provide some convenience, optimization of West Nile virus immune response could likely pose a substantial criterion for vaccine selection.”
As every horse has a unique set of needs, a standard one-size-fits-all equine vaccination program does not exist. The American Association of Equine Practitioners (AAEP) Vaccination Guidelines recommend an evaluation of each individual horse’s situation and vaccinating according to his needs.2 Dividing West Nile and equine influenza/equine herpesvirus (rhino) vaccinations into separate injections allows tailoring of each horse’s vaccination program.

The Equine Immunization Support Guarantee from Zoetis, the most comprehensive guarantee available, delivers additional confidence in your equine vaccination program. With the Equine Immunization Support Guarantee, if a horse shows clinical signs for an equine disease for which he was vaccinated, Zoetis will help cover the diagnostic investigation to determine with what the horse is infected. If diagnostics confirm disease, Zoetis will also cover diagnostic and therapeutic charges up to $5,000. To be eligible, a horse must be vaccinated by a veterinarian. Diseases covered by the Equine Immunization Support Guarantee include: rhinopneumonitis (equine herpesvirus types 1 and 4, respiratory), West Nile, equine influenza, tetanus, Eastern equine encephalitis (EEE), Western equine encephalitis (WEE) and Venezuelan equine encephalitis (VEE).

WEST NILE-INNOVATOR and FLUVAC INNOVATOR are the veterinarian and horse owner’s first choice for equine disease protection.3 Only INNOVATOR vaccines are adjuvanted with MetaStim®, a proprietary adjuvant system designed for safe, enhanced presentation of antigens to the horse’s immune system, featuring a dual-phase formulation shown to stimulate both cell-mediated and humoral immunity to West Nile virus for improved immune responses.4,5  

To learn more about how administering core and risk antigens separately helps protect horses from disease, visit

About Zoetis
Zoetis (zō-EH-tis) is the leading animal health company, dedicated to supporting its customers and their businesses. Building on more than 60 years of experience in animal health, Zoetis discovers, develops, manufactures and markets veterinary vaccines and medicines, complemented by diagnostic products and genetic tests and supported by a range of services. Zoetis serves veterinarians, livestock producers and people who raise and care for farm and companion animals with sales of its products in more than 100 countries. In 2015, the company generated annual revenue of $4.8 billion with approximately 9,000 employees. For more information, visit

For more information, contact: 
Sally Amtmann

Kassi Hoxmeier
Bader Rutter

1 Cortese V, Hankins K, Holland R, Syvrud K. Serologic Responses of West Nile Virus Seronegative Mature Horses to West Nile Virus Vaccines. J Equine Vet Sci. 2013;33:1101-1105.
2 American Association of Equine Practitioners. Vaccination Guidelines. 2012. Accessed June 1, 2016.
3 Data on file, MDI sales data for WEST NILE-INNOVATOR and FLUVAC INNOVATOR as of 12/31/15, Zoetis LLC.
4 Davis EG, Zhang Y, Tuttle J, et al. Investigation of antigen specific lymphocyte responses in healthy horses vaccinated with an inactivated West Nile virus vaccine. Vet Immunol Immunopathol. 2008;126(3-4):293-301.
5 Davis EG, Bello NM, Bryan AJ, et al. Characterisation of immune responses in healthy foals when a multivalent vaccine protocol was initiated at age 90 or 180 days. Equine Vet J. 2014. doi:10.1111/evj.12350.



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