A vaccine candidate against the deadly Nipah virus is set to begin early-stage human trials in April. This offers new hope against one of the world’s most dangerous emerging infections. The vaccine has been developed by researchers at the University of Tokyo. It will be tested in a Phase 1 clinical trial in Belgium, according to a report by Nikkei Asia.
Nipah virus was known for its high fatality rate and unpredictable outbreaks. Health authorities reported that the virus could kill between 40 percent and 75 percent of those infected. The outcome depended on early diagnosis and access to medical care. Despite this danger, there is no licensed vaccine or specific treatment available. This makes prevention efforts extremely difficult.
The new vaccine candidate was developed by researchers in Japan using a scientific approach that had already been proven safe in other diseases. According to researchers, a small portion of the Nipah virus genetic material was inserted into a weakened measles virus. This modified measles virus had been widely used in vaccination programs around the world for decades.
“When the vaccine is introduced in humans, antigen proteins similar to those of the Nipah virus are produced. The immune system’s response is seen strengthening the body’s defenses, helping to prevent the onset of symptoms,” the researchers explained. They added that the modified measles virus platform is chosen because of its long history of global use and safety.
Before moving into human trials, the research team tested the vaccine in animal studies, including experiments involving hamsters. These trials showed encouraging results, with scientists confirming both safety and a strong immune response. Based on these findings, regulators approved the move to Phase 1 human trials.
The upcoming Phase 1 clinical trial in Belgium is designed to include 60 healthy adult volunteers. The goal of this phase is not to confirm whether the vaccine could stop Nipah outbreaks. Instead, it is meant to ensure that it is safe for humans and capable of triggering an immune response. Researchers emphasized that this is important before moving to larger and more complex trials.
The trial attracted attention as Nipah virus cases are again being reported in South Asia. In January, India confirmed two Nipah infections in West Bengal, placing public health authorities on alert. While outbreaks are usually small, experts warned that each case carried a serious risk. This is due to the virus’s high death rate and potential for hospital-based transmission.
Nipah virus is classified as a zoonotic disease, meaning it spreads from animals to humans. Fruit bats are considered the natural hosts, with infections occurring through contaminated food or infected animals such as pigs. Also, infections can occur through close contact with infected people. Human-to-human transmission is especially dangerous in healthcare settings where prolonged exposure occurs.
In humans, Nipah infection ranged from mild symptoms to severe illness. Patients often experienced fever and headaches at first. But in many cases the disease progressed rapidly, leading to breathing problems or fatal encephalitis, a severe swelling of the brain. Treatment options are limited to supportive care. This further highlights the need for a preventive vaccine.
The University of Tokyo’s effort is part of a broader international push to address the Nipah virus before it causes a larger crisis. A team linked to Oxford University started Phase 2 clinical trials of another Nipah vaccine candidate in Bangladesh in December. That study is expected to include around 300 participants aged between 18 and 55. This shows growing global momentum.
The World Health Organization had already identified the Nipah virus as a priority disease under its Research and Development Blueprint. The designation reflected concerns that the virus had the potential to cause serious outbreaks if left unchecked. This is especially important in regions with frequent human-wildlife interaction.
Researchers and public health officials stressed that collaboration between countries is essential. Japanese scientists worked closely with European clinical centers to ensure that the trial met international safety standards. Experts said such cooperation is necessary for diseases that did not attract large commercial investment but posed serious global risks.
