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A substantial proportion of survivors of Nipah virus infection experience long-term neurologic deficits and fatigue, according to a study published yesterday in eClinicalMedicine.

The systematic review and meta-analysis, conducted by a team of British and Chinese researchers, analyzed evidence on post-acute sequelae after Nipah virus infection from eight studies published through November 2025.

Transmitted primarily by consumption of raw date palm sap that’s been contaminated by infected fruit bats, Nipah virus’ most prominent symptoms are acute encephalitis and respiratory disease. But instances of residual neurologic symptoms have been reported by survivors ever since the first outbreak of Nipah in Malaysia and Singapore in 1998 and1999.

“Synthesising information on pathogen epidemiology is critical for epidemic preparedness, and a better definition of disease burden has been identified as a strategic goal among key research priorities for the development of Nipah virus medical countermeasures,” the study authors wrote.

Nipah strain in India, Bangladesh could have different effects

Of the eight studies included, three consisted of hospitalized Nipah encephalitis survivors, and five included survivors of Nipah virus infection more broadly. All but one focused on survivors of the Malaysia/Singapore outbreak. 

Meta-analysis of five of the studies estimated the pooled prevalence of total residual neurologic effects at 45% among Nipah encephalitis survivors and 24% among survivors of Nipah virus infection. An estimated 10% of Nipah virus infection survivors experienced late-onset or relapsing neurologic symptoms after initial recovery.

The studies reported 34 different potential post-acute neurologic symptoms. In the only controlled study, total residual neurological deficits, fatigue, and excessive daytime sleepiness were significantly more prevalent in Nipah infection survivors than in household controls. 

The study authors caution that the data are limited and more evidence is needed from recent Nipah virus outbreaks in India and Bangladesh, which have been caused by a different strain of the virus, to get a better sense of the prevalence of long-term neurologic symptoms among survivors. 

“Estimates from this study may not be generalisable to this different clinical setting and viral strain,” they wrote.