The Coalition for Epidemic Preparedness Innovations (CEPI) is set to initiate Phase II clinical trials in Kenya for a human vaccine candidate against Rift Valley fever, building on successful Phase I results obtained in the UK. The study, supported by a $3.7 million grant from CEPI, will be jointly led by the University of Oxford and the Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme.
The upcoming trial will enroll 240 healthy adult participants, pending local regulatory approvals, to evaluate the safety and immunogenicity of the ChAdOx1 RVF vaccine. This vaccine utilizes the same ChAdOx1 platform that underpinned the Oxford-AstraZeneca COVID-19 vaccine.
Promising Results from Phase I Trials
Initial trials conducted in the UK indicated that ChAdOx1 RVF has a strong safety profile and is capable of inducing high levels of neutralizing antibodies, particularly at medium and high doses. These antibodies are crucial for blocking viral infection and providing immunity against Rift Valley fever.
Addressing a Critical Unmet Need
Rift Valley fever, a mosquito-borne disease, poses a significant threat to both human and animal populations, particularly in Africa and the Middle East. The disease is often transmitted through direct contact with infected animals or through mosquito bites. While most human infections result in mild symptoms, a small percentage of cases develop into a severe hemorrhagic form, with mortality rates reaching up to 50%. There are currently no licensed vaccines for human use, making the development of an effective vaccine a priority for global health organizations.
Dual-Use Potential
Studies have demonstrated that the ChAdOx1 RVF vaccine can protect multiple livestock species from Rift Valley fever, suggesting its potential for dual use in both human and animal health. This is particularly important for pastoral communities, where livestock losses can have devastating economic consequences.
Expert Perspectives
Professor George Warimwe, Principal Investigator of the trial and Deputy Executive Director of the KEMRI-Wellcome Trust Research Programme, stated, “Nearly 100 years after Rift Valley fever was discovered, there are still no approved vaccines or treatments against the disease. This vaccine trial brings us closer to addressing the rising frequency of outbreaks.”
Dr. Richard Hatchett, CEO of CEPI, emphasized the importance of the trial, saying, “Rift Valley fever disproportionately affects the lives and livelihoods of vulnerable pastoral communities, potentially causing both human fatalities and large-scale livestock losses. Investing in the promising human ChAdOx1 RVF vaccine diversifies CEPI’s portfolio and gives us a greater chance at protecting vulnerable populations against this worrisome threat that may become more prevalent with climate change.”
H.E. Dr. Jean Kaseya, Director General of Africa CDC, added, “The launch of a Phase II clinical trial of a Rift Valley fever vaccine candidate in an endemic country is a crucial milestone in our efforts to control this disease... The ChAdOx1 RVF vaccine offers hope to vulnerable populations who are disproportionately affected by the growing impact of climate change.”
