IAVI announced in August 2022 that volunteers for the PREVAIL clinical trial have been vaccinated with a novel vaccine candidate against Lassa fever virus (LASV). The Phase I clinical trial is called IAVI C1202 and is supported by the Coalition for Epidemic Preparedness Innovations (CEPI).  

According to IAVI LASV causes “significant annual outbreaks” of Lassa fever. It is endemic, or consistently present, across much of West Africa. Since 2022 the WHO has reported nearly 6,000 cases and more than 180 deaths since the start of 2022. Each year there are between 300,000 and 500,000 cases, although the specific numbers are unknown. There is currently no available vaccine.  

Through an existing partnership with CEPI, IAVI and partners were provided with up to $61.7 million to advance the LASV vaccine candidate through Phase I and II trials. CEPI’s goal is to produce a licensed vaccine for routine vaccine as part of its wider plan to “minimise or even eliminate the risk of future epidemic and pandemic threats”. The evaluation of this vaccine candidate is also supported by the Partnership for Research on Vaccines and Infectious Diseases in Liberia (PREVAIL). This is a Liberia-US collaboration since 2014. It was established by the Ministry of Health in Liberia and NIAID. 

The trial begins 

PREVAIL 12 is designed to “evaluate the vaccine candidate’s safety, tolerability, and ability to elicit an immune response against Lassa fever”. Vaccinations began at the Brigham and Women’s Hospital, East-West Medical Research Institute, and the George Washington University School of Medicine and Health Sciences. Around 100 healthy adults across the US and Liberia will participate. Results are expected in 2023 and will be distributed through open-access publications to increase the reach and benefit of the research.  

The vaccine is based on an attenuated strain of vesicular stomatitis virus (VSV). This has been modified to express a Lassa fever virus protein. The technology was developed by scientists at the Public Health Agency of Canada’s National Microbiology Laboratory. Further research and development are performed at IAVI’s Vaccine Design and Development Lab in Brooklyn, New York. It has become “one of the world’s leading viral vector vaccine” labs. The vaccine candidate was manufactured by Batavia Biosciences in Leiden, The Netherlands. Through partnership with Batavia IAVI “intends to develop an end-to-end platform for flexible, low-cost production of epidemic preparedness vaccines”.  

A “great step forward”  

Dr Swati Gupta, vice president and head of emerging infectious diseases and epidemiology at IAVI said that “continued Lassa fever outbreaks” emphasise the need to “realise rapid vaccine development and plan for widespread access before and during disease outbreaks”.* 

“We believe that IAVI’s rVSV technology offers a promising and validated new platform for development of vaccines” 

Using the “experienced, broader network of collaborators” in the trial she hopes to “glean important safety, tolerability, and immunogenicity data”. Dr Mark Kieh, PREVAIL’s principal investigator for IAVI C1202, described this potential to develop a vaccine as a “great step forward”. He hopes that such a vaccine would “reduce the disease burden”, particularly for rural communities who “continue to suffer the brunt of this disease”. CEPI’s Executive Director Vaccine R&D, Dr Melanie Saville, is reminded of the “disruptive power” of diseases like Lassa fever.* This “worrisome threat” needs a vaccine. She repeated Dr Kieh’s suggestion that this is a “great step forward” and looks forward to seeing results.  

*We look forward to hearing from Drs Swati Gupta and Melanie Saville at the World Vaccine Congress in Europe this October. Get your tickets at this link to join us!