Kozhikode: The test results of the four Nipah patients undergoing treatment in Kerala's Kozhikode returned negative on Friday.

All the patients including the 9-year-old boy who was critical have tested double negative, Kerala Health Minister said. Double negative implies that the two samples of each Nipah patient taken after a specific time interval tested negative. With this the patients have become completely free of the deadly virus.

The boy was infected after exposure to his father, the first Nipah victim in 2023. He was on ventilator support at MIMS hospital Kozhikode from 9th September till 16. The victim's brother-in-law, a health care worker from Iqraa Hospital in Kozhikode and a Cheruvannur native are the other three patients who tested negative. As of September 28, the number of people under observation is 649.

The Kerala government has withdrawn containment in all zones and allied restrictions imposed in northern Kozhikode district as no new cases of Nipah virus have been reported here since September 16.

In a Facebook post on Tuesday, District Collector A Geetha said all schools located in the areas that fell within containment zones would be opened and regular classes would commence on Wednesday.

However, the collector urged people to continue their vigil against the virus infection, maintain social distancing and ensure the use of masks and sanitizer.

All the institutions in the district had been closed since September 14, and online classes were being held after the virus outbreak was declared in the state on September 12.

A total of six people were confirmed to have been infected by the virus till date, and of them, two died. Of the two deaths, the first person who died on August 30 was found to be the index case, or patient zero, from whom others caught the infection.

As of September 24, the number of people under observation was 915, but none of them were in the high-risk category, health authorities said.

The number of samples tested till then was 377, and the number of negative results was 363, they added.

In the Nipah virus outbreak in Kerala in 2018, the first case was reported on May 19, 2018. By June 1, 2018, 18 patients tested positive for the virus and 17 of them died. Then the outbreak was confined to Kozhikode and Malappuram districts. 

The doctors have brought down the mortality rate to 33% from 94% in 2018. This time, the doctors managed to save all four patients who tested positive for the virus. Mohammed Ali and Mangalatt Haris, who succumbed to the virus, died before they were diagnosed with Nipah virus infection.