livestock in Tanzania

Rift Valley Fever Vaccines

Next-Generation Vaccines for Rift Valley fever

There is currently no vaccine approved to protect humans against Rift Valley fever.

To meet this need, the Coalition for Epidemic Preparedness Innovations (CEPI) has selected the UC Davis One Health Institute as part of a multi-institutional multi-year collaborative effort including the Colorado State University, the US Centers for Disease Control and Prevention (CDC), and the Ifakara Health Institute (Tanzania) to evaluate the suitability of “DDvax” a live-attenuated rationally designed candidate vaccine for Rift Valley fever virus for use as a human vaccine. This candidate vaccine was developed initially at the CDC and contains a complete gene deletion of all known virulence factors rendering the vaccine highly attenuated and unable to be transmitted by mosquitoes.

Over the past 15 years, this candidate has proven itself safe and effective in preventing RVF infection and disease in a variety of animal models ranging from rodents to livestock to non-human primates. Now with support from CEPI, our consortium is working to generate cGMP vaccine stocks and complete final pre-clinical safety and immunogenicity evaluations of DDvax in preparation for eventual human safety and immunogenicity trials in endemic areas across Africa.

What is Rift Valley fever?

Rift Valley fever is a high-consequence pathogen of people and animals found throughout Africa and parts of the Middle East. Rift Valley fever virus is mosquito-borne and is a classic example of the multi-faceted intersection of human and animal health and vector ecology that characterize the One Health aspects of zoonotic arboviruses.

First identified in the 1930s, RVF outbreaks can be severe, with multiple large-scale outbreak (>50,000 to 200,000 cases) occurring periodically across Africa. The rapid and sudden development of tens of thousands of human cases and the widespread agricultural impact on potentially millions of livestock have challenged public health infrastructures to cope with the magnitude of these outbreak emergencies. Lethality among livestock animals is very high (30-90%) and is typically followed a few weeks later by explosive incidence of human cases due to transmission from infected mosquitoes or contact with virus contaminated livestock tissues, fluids, or aborted materials.  Among severe human cases, RVF can manifest clinically as hepatitis, retinitis, delayed onset encephalitis, and a hemorrhagic syndrome with high case fatality.

Because of these devastating effects, in 2018 the World Health Organization included RVF as one of the top ten priority R&D blueprint diseases due to its potential to generate a public health emergency, with no currently approved preventive and curative solution.