In Malaysia in the fall of 1998, a mystery ailment swept through the local pig-farming community, leading to 105 deaths. Another 160 individuals experienced acute encephalitis of varying severity. Local authorities originally attributed the ailment to a disease called Japanese encephalitis, preventing the ailment from being contained in its early stages.
Eventually, the cause was pinpointed: a novel virus spread by fruit bats. During the 1998 outbreak, fruit bats spread the virus to pigs which subsequently spread the virus to humans. The virus was coined as Nipah virus (NiV). Due to the initial uncertainty surrounding the origin of the virus, the outbreak spread to the point where over a million pigs were culled in response, leading to a near collapse of the local pig farming industry.
Once infected with Nipah virus, a person may experience symptoms of a fever, headache, drowsiness, and mental confusion. These symptoms may escalate to coma and swelling of the brain (also called encephalitis) within 24 to 48 hours. Cases of Nipah virus range in severity, but can cause severe illness or death in up to 75% of those infected.
Since the virus can spread from fruit bats to pigs, individuals in areas where Nipah virus is known to spread should avoid exposure to sick pigs. Additionally, the sap of the date palm plant can be infected with the virus by an infected bat. Individuals should avoid drinking raw date palm sap to avoid infection.
On July 11, 2022, a phase 1 trial of a Nipah virus vaccine, manufactured by Moderna, was launched by the National Institute of Allergy and Infectious Diseases (NIAID). Since the original outbreak that began in 1998, outbreaks have occurred almost annually in Asia, primarily in Bangladesh and India.
Though the number of cases and their spread is still well contained, the threat of this virus is seen as significant enough to warrant a new approach in how this virus is contained. The NIAID has characterized Nipah virus as a virus that has the potential to cause a future pandemic, warranting substantial effort into understanding and combating the virus before a pandemic arises.
According to NIAID Director Anthony Fauci, “Nipah virus poses a considerable pandemic threat because it mutates relatively easily, causes disease in a wide range of mammals, can transmit from person-to-person, and kills a large percentage of people it infects. The need for a preventative Nipah virus vaccine is significant.”
Phase 1 of the trial will test the vaccine for safety, tolerability, and ability to generate an immune response in 40 adults. Should the trial succeed, subsequent trials will test the vaccine in a larger cohort.
Sources: Malaysian Journal of Pathology, Centers for Disease Control and Prevention, National Institutes of Health