Trials for a human vaccine for Rift Valley fever will soon begin, giving hope that a vaccine will be released in the next five years.

The Coalition for Epidemic Preparedness Innovations (CEPI), which has been working on the inoculation, says trials will take three to four years.

Seventeen candidates are thought to currently be in preclinical stages, and CEPI will select a handful of these to advance forward as part of its new funding award.

“We estimate that the initial trial projects will likely take three to four years to complete,” CEPI project leader Mike Whelan said this week.

“After that, depending on available data, successful vaccines will move forward into efficacy trials before a licence for human use can be granted,” he added.

The efficacy trials will determine whether people in the clinical trial who got vaccinated with the Rift Valley fever vaccine are less likely to develop the disease than those who got the placebo shot.

CEPI estimates that approval of the Rift Valley fever vaccine, at least for emergency use, will happen within a five to 10-year period.

Rift Valley fever is an acute viral haemorrhagic disease caused by the Rift Valley fever virus, transmitted by mosquitoes (Aedes, Culex, Anopheles, and Mansonia spp) and blood feeding flies. It commonly affects domesticated animals (such as cattle, sheep, goats, and camels) but can also cause illness in people.

No vaccines are currently approved for human use, even though climate change could increase the severity and frequency of its outbreaks among human communities.

In East Africa, its outbreaks are associated with cycles of heavy rainfall that result in floods and increased vegetation cover favouring high vector density and species diversity.

During the 2006-2007 outbreak in East Africa, the fever caused a $60 million loss of trade due to livestock deaths and animal abortions.

The virus has been reported in 30 countries across the world and there have been heavy cases in Kenya, Mauritania, Uganda and Egypt over the past 40 years.

CEPI is supporting two vaccine programmes at the Wageningen University in the Netherlands and Colorado State University in the US.

Last month, CEPI launched its second phase of funding to advance the development of innovative vaccine programmes against Rift Valley fever, including $35 million financial support provided by the European Union Horizon Europe programme. Up to $50 million in total will be made available by CEPI to support promising Rift Valley fever vaccine candidates through Phase I and II clinical trials in endemic areas.