Recombinant H5N1 Avian Influenza Vaccine for Cats
A study recently published in the scientific journal npj Vaccines demonstrates that a recombinant H5 protein-based vaccine effectively prevents severe morbidity and mortality in cats exposed to the H5N1 avian influenza virus, while significantly reducing viral shedding into the environment.
In recent years, the H5N1 avian influenza virus (Clade 2.3.4.4b) has emerged as a significant global threat, affecting not only avian species but also a wide range of mammals. Domestic cats are particularly vulnerable due to their high susceptibility to the virus and the increased likelihood of contact with infection sources. Recent outbreaks in the United States have linked feline infections to the consumption of unpasteurized milk from infected dairy farms or contact with diseased wild birds. In felines, the disease typically manifests in a severe form characterized by exceptionally high mortality rates. A collaborative team of researchers from Cornell University and Medgene laboratories developed and evaluated a subunit vaccine based on the virus's H5 Hemagglutinin (HA) protein. The vaccine was produced using a baculovirus expression system in insect cells and formulated with an aluminum hydroxide adjuvant.
The study population consisted of 16 healthy 12-month-old cats, divided into two groups:
-Vaccinated Group (n=8): Received two doses of the vaccine administered subcutaneously on day 0 and day 21.
-Control Group (n=8): Remained unvaccinated.
Viral Challenge: On day 35 of the trial, all subjects were challenged intranasally and orally with a bovine-origin H5N1 virus (Genotype B3.13).
Survival Rates: 100% of the vaccinated cats survived the viral challenge and remained asymptomatic (with the exception of one cat exhibiting mild, transient clinical signs). In contrast, only one cat (12.5%) in the control group survived.
The vaccine elicited high titers of neutralizing antibodies in the blood. Vaccination significantly reduced viral shedding from nasal, oral, and fecal routes compared to the control group.
The study concludes that this recombinant subunit vaccine is safe and highly efficacious in preventing morbidity and mortality associated with avian influenza in cats, offering a robust tool for mitigating the spread of the virus in high-risk environments.
