Same Vaccine Concept for Ebola Appears Effective Against Nipah Virus
Credit: J. EPSTEIN, ECOHEALTH ALLIANCE © 2014
Giant fruit bat, a reservoir of Nipah virus.
The public health community has recently been challenged with simultaneous outbreaks of Ebola and Nipah viruses in different parts of the world. Interestingly, the same experimental vaccine concept being used to prevent Ebola in the Democratic Republic of the Congo (DRC) also is the basis for an experimental vaccine against Nipah, which last month infected at least 18 people in India, 17 of whom died.
As of June 21, 3,199 people had received the experimental Ebola virus vaccine in the DRC after being deemed at risk of possible exposure to the virus; vaccinations began May 21. Researchers based in Canada developed the concept for that vaccine nearly two decades ago. Several of those researchers are now at NIAID, and they and their colleagues continue to test that same concept to prevent and treat several other viruses, such as Nipah, Marburg, Lassa, Zika, Hendra, and MERS.
What is the concept for assembling the vaccines? Imagine a semi-truck hauling freight in a trailer. The semi-truck would be vesicular stomatitis virus (VSV), which can harm cattle but rarely causes symptoms in people. That makes VSV a viable tool for transporting proteins from other viruses into people. Ideally, as with any vaccine, the body will later recognize those proteins if ever infected by that virus and begin protecting itself. The “trailer” that VSV hauls are the viral proteins; a significant part of the research work is identifying which proteins work best to trigger the strongest immune response. Then they must insert those proteins into VSV, test the assembly for viability, determine optimal dosage, and check for adverse reactions.
The NIAID Laboratory of Virology group, located at Rocky Mountain Laboratories in Hamilton, Mont., has successfully tested its Nipah virus vaccine in hamsters (Blair DeBuysscher et al., 2014) and African green monkeys (Joe Prescott et al, 2015). Now, they are collaborating with vaccine company PaxVax to move the Nipah vaccine further along. PaxVax has applied for funds from the Coalition for Epidemic Preparedness Innovations—a mix of private and public funders aligned around the cause of speeding vaccine development. Funds would go toward additional preclinical studies, manufacturing production, and phase I and II clinical trials in the United States and Bangladesh, which has experienced Nipah virus outbreaks almost every year since 2001.
Nipah virus, first identified in Malaysia in 1999 when it killed 105 people, is spread by fruit bats in Southeast Asia and India. The virus targets the lungs and causes brain swelling. While infection is rare, the disease is fatal between 40 and 75 percent of the time. Those who survive often experience chronic brain damage.
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