A World Health Organisation official yesterday said the risk of the spread of the Nipah virus is low, saying that none of the over 190 contacts of the two people infected in India had tested positive or developed symptoms of the disease.
Hong Kong, Malaysia, Singapore, Thailand and Vietnam are among the Asian locations that tightened airport screening checks this week to guard against such a spread after India confirmed infections.
"The risk on a national, regional and global level is considered low," Anais Legand, an official with WHO's Health Emergencies Programme, told a Geneva press briefing, saying that neither person travelled while symptomatic. Both of the infected patients are hospitalised and are alive, she added, with one showing signs of improvement.
Legand said the WHO was waiting for India to release the sequence of the virus to assess any possible mutation but said there was "no specific evidence that would make us worry for the time being".
Carried by fruit bats and other animals, the virus can cause fever and brain inflammation. It has a fatality rate ranging from 40% to 75%, with no cure. Vaccines in development are still being tested.
The source of this infection is not yet fully understood. Hypotheses such as infection from drinking palm juice or exposure at healthcare facilities are being considered, Legand said.
Meanwhile, several leading experts yesterday said the airport screenings for Nipah virus, which have been stepped up across Asia this week, are more about reassurance than science,
The WHO yesterday said it did not currently recommend airport screening.
"Based on what we currently know, there is a very low likelihood that this outbreak will cause a large international epidemic,” said Dr Md Zakiul Hassan, a Nipah specialist at icddr,b, a global health research institute in Bangladesh, where Nipah cases are reported almost every year.
Piero Olliaro, professor of poverty-related disease at the University of Oxford, said airport screenings for such a rare disease were likely to be ineffective.
"Countries sometimes do these things just to show them flexing the muscles... telling their people that they're doing something to protect them,” he said. Olliaro and other public health experts said airport temperature screenings rarely worked to stop the spread of disease. During Covid-19, for example, they missed the majority of cases, studies have shown.
Also, many illnesses can cause a fever, and follow-up testing for a rare disease like Nipah is time-consuming, the experts added. Instead, the world’s focus on Nipah would be better directed at better understanding the virus where it currently spreads, and protecting those at risk from it with new vaccines and treatments.