IPNEWS: On May 13, 2024, participants in Monrovia, Liberia, were vaccinated with a Lassa fever vaccine candidate as part of a Phase 2a clinical study (NCT05868733). This is the first Phase 2a clinical trial of any Lassa vaccine candidate. The same candidate previously completed Phase 1 clinical studies of vaccine safety.
The Liberian arm of the Phase 2a clinical study is being conducted by The Partnership for Research on Vaccines and Infectious Diseases in Liberia (PREVAIL). PREVAIL is a clinical research partnership involving the Liberian Ministry of Health; the National Public Health Institute of Liberia; the John F. Kennedy Medical Center; the U.S. National Institutes of Health (NIH) through the Frederick National Laboratory for Cancer Research, currently operated by Leidos Biomedical Research, Inc.; the U.S. Centers for Disease Control (CDC); and the World Health Organization (WHO). IAVI, a nonprofit scientific research organization, is the study sponsor and developer of the Lassa fever vaccine candidate. The study is funded by The Coalition for Epidemic Preparedness Innovations (CEPI) and the NIH’s National Institute of Allergy and Infectious Diseases.
The Lassa fever vaccine candidate being tested is similar to ERVEBO®, Merck’s Zaire ebolavirus (ZEBOV) vaccine that was originally tested in the PREVAIL 1 Ebola vaccine study conducted in 2015 in Liberia and also in the PREVAC study by Liberia, Guinea, and Sierra Leone. ERVEBO® is now licensed for adults and children by the U.S. FDA.
The Phase 2a study is designed to evaluate the potentially protective immune responses of this candidate Lassa fever vaccine against the Lassa virus. It will seek to enroll a total of 612 healthy volunteers in Nigeria, Ghana, and Liberia between the ages of 18 months to 70 years old. PREVAIL is expected to enroll 204 participants at the JFK Hospital, PREVAIL’s site in Monrovia, Montserrado County. The study will last for up to two and a half years.
Lassa fever is a viral disease carried by rats in West Africa. Humans acquire the disease primarily through food or household items contaminated with the urine of infected rats. The disease also can be transmitted from person to person through contact with the infected person’s feces, urine, blood, or other body fluid.
The WHO estimates that 80% of infected individuals with the Lassa virus have no symptoms. Approximately 20% of infected individuals develop severe disease, which can affect the liver, spleen, and kidneys. Lassa fever can also cause hearing loss.
There is currently no vaccine for the prevention of Lassa fever. Lassa fever outbreaks occur in several West African countries, including Nigeria, Guinea, Benin, Sierra Leone, Togo, and Liberia.
PREVAIL physician Dr. Kumblytee D. Johnson will lead the Lassa fever Phase 2a vaccine study at the JFK Hospital PREVAIL’s site. Dr. Johnson stated that, “beyond its annual toll of around 300,000 cases, Lassa fever claims over 5,000 lives yearly and leaves survivors grappling with post-acute complications. The collaborative effort of PREVAIL and IAVI to conduct this trial seeks to create a safe and efficacious vaccine to mitigate the disease impact and its aftermath, particularly in West Africa, where its burden is most acute.”
Funding support is from 1) CEPI through a subcontract from IAVI and 2) the National Institute of Allergy and Infectious Diseases. Twenty-six percent ($580,031) will be financed with United States Government funds and seventy-four percent ($1,648,389) will be financed with non-government funds.
