Marburg vaccine shows promising results in first-in-human study
The Marburg virus (MARV) experimental vaccine was safe and elicited an immunological response in a small, first-in-human clinical trial, according to a recently published paper in The Lancet. Researchers at the National Institute of Allergy and Infectious Diseases (NIAID), a division of the National Institutes of Health, created the vaccine, which could someday be a crucial tool in combating Marburg virus epidemics.
cAd3-Marburg, an investigational MARV vaccine candidate created at NIAID’s Vaccine Research Center, was tested in this first-in-human, Phase 1 research (VRC). The modified chimpanzee adenovirus used in this vaccine, known as cAd3, has been altered such that it can no longer reproduce or infect cells. It also shows a glycoprotein found on the surface of the MARV virus, which triggers immune responses against the virus. When employed in investigational Ebola virus and Sudan virus vaccines produced by the VRC, the cAd3 vaccine platform displayed a satisfactory safety profile in earlier clinical studies.
A significant portion of those infected by MARV, an Ebola virus-related filovirus, experience a fast progressing febrile illness that ends in shock and death. Many researchers believe that MARV illness epidemics in people start when the virus leaves its primary animal host, which is likely to be a small number of sub-Saharan African bats that have been infected for a long time. Similar to the symptoms of an Ebola virus infection, MARV sickness can cause fever, headache, chills, rash, abdominal discomfort, vomiting, and diarrhoea. Patients may experience multiple organ malfunction, psychosis, and severe bleeding from the gastrointestinal tract or other places as the condition worsens, which can be fatal.
Apart from supportive care, there are no licenced vaccinations or specialised treatments for MARV illness. Although numerous experimental vaccinations have been developed in the past, none have shown to be both extremely efficient and capable of offering long-lasting protection. A single-dose vaccine with long-lasting protection for recipients would be essential for controlling outbreaks in regions of Africa where a Marburg vaccine is most needed.
In this study, 40 healthy adult volunteers were enrolled at the Walter Reed Army Institute of Research Clinical Trials Center in Silver Spring, Maryland. The trial’s safety results were encouraging: There were no serious adverse events, and the experimental vaccine was well-tolerated. One participant in the higher dose group developed a fever following vaccination, but it resolved by the following day. In addition, the investigational vaccine appeared to induce strong, long-lasting immunity to the MARV glycoprotein: 95% of participants in the trial exhibited a robust antibody response after vaccination, and 70% maintained that response for more than 48 weeks.
Plans are in place to conduct further trials of the cAd3-Marburg vaccine in Ghana, Kenya, Uganda, and the United States. If additional data supports the promising results seen in the Phase 1 trial, the cAd3-Marburg virus vaccine could someday be used in emergency responses to MARV outbreaks.