The Coalition for Epidemic Preparedness Innovations (CEPI) and The University of Tokyo (UTokyo) have announced a partnering agreement worth up to $31 million to advance the development and manufacture of a vaccine against the Nipah virus—a bat-borne virus that can spread to both humans and livestock. Stanford epidemiologist Stephen Luby will be in charge of related human testing in Bangladesh (read related Q&A with Luby).
To produce a vaccine against Nipah virus, researchers at UTokyo have inserted Nipah virus genes into an attenuated measles viral vaccine. During the replication of the measles vector, the antigens of the Nipah virus are expressed, inducing a strong and long-term immune response against the virus.
This kind of recombinant vaccine—specifically using measles vaccine as a vector—can induce powerful humoral immune responses (ie, antibody-mediated immunity) and cellular immune responses (ie, T-cell mediated immunity), which could lead to effective protection against Nipah virus. This vector approach is also being used by UTokyo to evaluate an experimental vaccine against highly pathogenic avian influenza. The European Vaccine Initiative has also supported this vector approach to develop vaccine candidates against Zika and Dengue viruses with funding from the European Commission Horizon2020 programme and the Global Health Innovative Technology Fund, respectively
In view of its high virulence, animal-to-human and human-to-human spread, significant morbidity and mortality, and potential to cause significant societal and economic disruption, Nipah virus has been listed as a priority pathogen by the WHO and a category C Bioterrorism agent by the CDC. Nipah virus is a paramyxovirus (genus Henipavirus). Transmission of Nipah virus to humans can occur after direct contact with infected bats, infected pigs, or from other infected people. The virus was first identified in 1999 during an outbreak of illness affecting pig farmers and others having close contact with pigs in Malaysia and Singapore. Over 100 human deaths were reported, and over a million pigs were killed in the effort to stop the outbreak.
In May 2018, India experienced an outbreak in the southern state of Kerala. A total of 19 cases of Nipah virus were reported, including 17 deaths (case fatality rate: 90%). During this outbreak, more than 2500 contacts of Nipah patients were monitored by the state surveillance system. By mid-June, the Kerala government and the Union Health Ministry announced that the outbreak had been contained. No approved vaccines against or treatments for Nipah virus are currently available.
UTokyo has developed a Nipah vaccine candidate using a measles vector. This vaccine candidate was constructed by inserting the Nipah-virus G gene (Malaysia strain) into a measles vector (Edmonston B strain). The Institute of Medical Science, UTokyo, will co-lead this CEPI-funded project with the European Vaccine Initiative. Phase 1 and phase 2 trials will be undertaken in partnership with the Stanford University School of Medicine and the International Centre for Diarrhoeal Disease Research, Bangladesh. Batavia Biosciences will manage vaccine manufacturing and stockpiling.
About the Nipah virus
Nipah virus belongs to the Paramyxoviridae family of viruses, genus Henipavirus, alongside Hendra virus. Nipah is a zoonotic disease, meaning it passes from animals to humans. The natural hosts of the virus are fruit bats (also known as flying foxes) of the genus Pteropus. Nipah virus can be spread to people from infected bats, infected pigs, or infected people.
Nipah virus infection can cause severe, rapidly progressive illness that affects the respiratory system and the central nervous system, including inflammation of the brain (encephalitis). Symptoms begin between five and 14 days after infection, and include fever, altered mental state, cough and respiratory problems.
People are advised to avoid contact with ill pigs and bats in countries where Nipah virus is known to occur. They are also advised to avoid drinking raw date palm sap, which can be infected with bodily fluids from bats. There are currently no vaccines or specific therapeutics against Nipah virus approved for use in humans.