Feline vaccine may soon be available on the European market

A vaccine relying on RNA technology to protect cats against feline leukemia virus (FeLV) is now recommended for market authorization in the European Union. The European Medicines Agency (EMA) recently granted the recommendation to Nobivac NXT HCPChFelV (Merck Animal Health), the first veterinary vaccine containing self-amplifying RNA as an active substance to receive the agency’s market authorization support.¹

Merck Animal Health launched the Nobivac NXT HCPChFelV vaccine in the US, in 2024, as a protection against feline leukemia virus (FeLV). An expansion of the Nobivac NXT vaccination, which was previously approved by the USDA, Nobivac NXT HCPChFelV also provides protection against other feline infectious diseases.²

This vaccine targets feline herpesvirus type 1, feline calicivirus, feline panleukopenia virus, and Chlamydia Felis, a bacterium that primarily causes eye infections, in addition to FeLV.^1,2 According to the EMA, the Nobivac NXT HCPChFelV vaccine contains live attenuated strains of these targeted pathogens, which stimulate an immune response and help the body recognize the microbes. A rapid and effective response is then triggered if the feline comes into contact with them in future.¹

“For feline leukemia virus, the vaccine also contains self-amplifying RNA packaged in a replication-deficient viral replicon particle. The particle delivers the RNA to cells, enabling the production of a feline leukemia virus protein that triggers an immune response and prepares the body for future exposure to the virus,” the EMA stated in a news release.¹

The vaccine is a nonadjuvanted, low volume 0.5 mL dose vaccine that is intended to be administered in 2 doses, separated by 3 to 4 weeks, according to Merck and the recommendation of the American Association of Feline Practitioners (AAFP). The product has a proven duration of immunity of 2 years, according to the AAFP.^2-5

FeLV is a common infectious disease in cats, and is considered a retrovirus. It often spreads through mutual grooming, fighting behavior, and shared food, water, and litter. Infected cats can shed infectious viral particles in their saliva, feces, urine, and milk. Although any cat exposed to the virus is susceptible to a FeLV infection, kittens are at a greater risk than adult cats because of their immature immune systems, according to Cornell University College of Veterinary Medicine.^2-4

“Nearly 4% of cats in North America alone are affected by this disease, a notable percentage when there have been guidelines for prevention in place for decades, and especially since the virus can lead to life-threatening diseases,” Meg Conlon, DVM, an executive director for Merck Animal Health, said in an earlier statement.^2,3 “That’s why education and awareness of the importance of vaccinating against this disease is so important.”

References

1. EMA recommends authorization of first veterinary vaccine using RNA technology. News release. European Medicines Agency. April 17, 2026. Accessed May 11, 2026. https://www.ema.europa.eu/en/news/ema-recommends-authorisation-first-veterinary-vaccine-using-rna-technology
2. Littrell A. New vaccine protects against feline leukemia virus. dvm360. September 24, 2024. Accessed May 12, 2026. https://www.dvm360.com/view/new-vaccine-protects-against-feline-leukemia-virus
3. Merck Animal Health Announces Expansion of NOBIVAC NXT Platform with the First and Only RNA-Particle Technology Vaccine for Feline Leukemia Virus. News release. Merck Animal Health. September 24, 2024. Accessed May 12, 2026. https://www.businesswire.com/news/home/20240924377048/en/Merck-Animal-Health-Announces-Expansion-of-NOBIVAC%C2%AE-NXT-Platform-with-the-First-and-Only-RNA-Particle-Technology-Vaccine-for-Feline-Leukemia-Virus
4. Feline Leukemia Virus. Cornell University College of Veterinary Medicine. Accessed May 12, 2026. https://www.vet.cornell.edu/departments/cornell-feline-health-center/health-information/feline-health-topics/feline-leukemia-virus
5. Nobivac NXT FeLV. Merck Animal Health. Accessed May 12, 2026. https://www.merck-animal-health-usa.com/nobivac/nobivac-nxt-felv#overview