Nipah virus outbreak in India
The WHO says the outbreak risk is currently low to moderate but has warned that Nipah’s high fatality rate and lack of a licensed vaccine make continued surveillance essential. Ömer Faruk Yıldız/Unsplash

Health authorities are monitoring a limited outbreak of the Nipah virus in eastern India after confirmed infections were reported in West Bengal in late December 2025 and January 2026.

Indian officials confirmed two cases of the virus in healthcare workers in Barasat, north of Kolkata, triggering extensive contact tracing and testing. The cases have drawn international attention because Nipah virus has a high fatality rate and no licensed vaccine or targeted treatment.

The World Health Organization (WHO) has assessed the public health risk as moderate at a sub-national level and low at national, regional and global levels. The agency has nonetheless stressed the need for continued surveillance, rapid response and preparedness as research into vaccines and treatments continues.

Confirmed Cases and WHO Assessment

India's National Institute of Virology confirmed the two cases on 13 January 2026 after laboratory testing. Both patients developed symptoms associated with severe Nipah virus infection, including fever, headache and respiratory complications.

Health authorities identified and tested more than 190 close contacts of the infected individuals. All tests returned negative results, suggesting that containment measures were effective at an early stage.

In its Disease Outbreak News update, the WHO said there was no evidence of sustained human-to-human transmission beyond close contact. It added that strict infection control measures and rapid case identification were essential to prevent further spread.

No Licensed Vaccine or Targeted Treatment

A key challenge associated with Nipah virus is the absence of approved vaccines or antiviral drugs. According to the WHO, treatment remains limited to supportive care, including rehydration, respiratory support and management of complications.

The virus is included on the WHO's Research and Development Blueprint of priority pathogens due to its epidemic potential and historically high mortality rates, which have ranged between 40 per cent and 75 per cent in previous outbreaks.

International research efforts are continuing to explore vaccine candidates and therapeutic approaches. Health agencies say this work is aimed at improving preparedness in the event of larger outbreaks in future.

Symptoms and Transmission

Nipah virus infection often begins with flu-like symptoms such as fever, headache, muscle pain and vomiting. In some cases, the illness progresses to severe respiratory disease or encephalitis, an inflammation of the brain.

The virus is zoonotic, meaning it can spread from animals to humans. Fruit bats are considered the natural host, with transmission occurring through contaminated food or direct contact. Limited human-to-human transmission has been recorded in past outbreaks, typically involving close physical contact.

International Monitoring and Travel Advice

The WHO has said that travel and trade restrictions are not recommended at this stage. However, several countries in Asia have increased health screening measures at airports and other points of entry as a precaution.

In the UK, the UK Health Security Agency said it was monitoring developments closely and working with international partners. UK health authorities have advised clinicians to consider travel history when assessing patients with compatible symptoms.

Public health guidance continues to emphasise good hygiene practices, avoidance of potentially contaminated food, and prompt medical assessment for anyone who becomes unwell after travelling to affected areas.

Ongoing Vigilance

While the current outbreak appears limited, health agencies have said continued monitoring is essential given the virus's characteristics. Surveillance, rapid response systems and ongoing research remain central to global efforts to reduce the risk of wider transmission.

The WHO has reiterated that early detection and coordinated public health action are key to managing Nipah virus outbreaks and preventing future epidemics.

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