NEW DELHI: An expert panel under the Indian Council of Medical Research (ICMR) has proposed using the recovered Covid-19 patients as volunteers as part of an epidemiological exercise.

To begin with, the cured coronavirus patients in isolation and quarantine centres in Tamil Nadu and West Bengal could be studied, sources privy to the development said.

While it is not yet clear how long do the antibodies generated in those infected with coronavirus last, it has now emerged that the virus triggers T-cell mediated immunity in the infected people - which is considered good.

“T-cells are memory cells which means that even when the antibody levels go down in those infected, the person will have long-lasting protection against the disease in case of any future exposure,” a member of the expert group on Covid-19 surveillance and epidemiology under the ICMR said.

“So while we are not confident enough to call it an immunity passport yet, we do have some understanding now that exposed people will have a long-term protection against the disease. We are thinking of utilising it and also studying its impact,” he said.

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A recent research by the scientists at Sweden's Karolinska University, which studied over 200 patients, has shown that robust T-cell mediated immunity was found in all convalescent patients even in the absence of antibodies.

The scientists said that exposed family members and about 30 per cent of healthy individuals who donated blood in May, were found to have T-cell immunity against the infection as well - apart from previously infected patients who were studied. Though, those with severe disease had a more robust T-cell response than those with mild or asymptomatic disease.

Another member of the expert panel said that in India many states, on the other hand, are struggling to find enough frontline workers for a large number of quarantine and isolation centres as sometimes even nurses are wary of going close to the infected or suspected patients.

“Therefore, it will serve the dual purpose of solving the problem of manpower shortage in required places and also studying the immunological response behaviour in recovered patients who are otherwise healthy if we use them as volunteers," he said.

As a pilot, the experiment could soon start in some districts in Tamil Nadu and West Bengal — two states that have shown interest in the proposal mooted by the ICMR expert group so far and could be later expanded in other states as well.