Herd immunity needed to combat Coronavirus infection: Indian public health expert

'There is no alternative to herd immunity. In a nation of 1.3 billion people the herd immunity strategy, would allow a majority of the population to gain resistance to the virus by becoming infected and then recovering. It could also result in less economic devastation and human suffering than restrictive lockdowns designed to stop the virus,' prominent  Epidemiologist and visiting Professor at the Kolkata based West Bengal University of Health Sciences, School of Public Health, Dr Naresh Purohit told UNI here today.

'No country can afford a prolonged period of lockdowns and least of all a country like India,' Dr Purohit pointed out.

In fact, in an interview to the BBC, a repeat telecast this morning, Dr David Nabarro, World Health Organisation's special envoy for Covid-19, said "we must learn to live with it" (the pandemic).
He told Hardtalk's Stephen Sackur that it was not known how long it would take to develop a treatment or a vaccine.

'We have all got to learn to live with this virus, to do our business with this virus in our presence, to have social relations with this virus in our presence and not to be continuously having to be in lockdown because of the widespread infections that can occur,' Mr Nabarro told his interviewer.

Dr Purohit, who is also National Integrated Disease Surveillance Programme Advisor, stated that we may be able to reach a point of herd immunity without infection really catching up with the elderly. And when the herd immunity reaches a sufficient number the outbreak will stop and the elderly would also be safe.

'The lockdown would have limited impact on the spread of the Coronavirus, preventing only 20-25 per cent of infections that might eventually be detected at the peak of the pandemic,' the physician explained. He expressed concern that the lockdown has caused economic hardship, pain and suffering particularly to the poor.

'In a lockdown we are not confronting the virus but simply trying to hide from it. Once the lockdown is lifted, the virus, which has not disappeared, will hit us again. The only way a lockdown can be an effective defence against the virus is if it continues for twelve months  or more till a vaccine is discovered. But that is a prospect which seems unfeasible,' he reasoned.

Dr Purohit explained that herd immunity means allowing India’s young population to expose themselves to the virus and build up immunity. Approximately 70 per cent will have to acquire immunity for herd immunity to be effective. At that point, it will also cover the elderly, who are most at risk.

'In trying to build herd immunity, India has a great advantage over countries like the US, the UK, Italy, Spain and France because of the age profile of its population. Close to 90 per cent of Indians are under the age of 60. The experience of the virus in all other countries has established that people under 60, because of their resilience, either do not get infected or are infected only sub-clinically,' he added.

The doctor, however, said a small percentage of this age group will develop the disease and an even smaller fraction of them will die (which in India may still amount to a few lakh people over a period of one to two years).

Dr Purohit apprehended that "this is the cost that has to be paid" to keep the rest of India safe.

'This is the sacrifice India is asking of its young population so that the country as a whole can survive,' the physician noted.

Dr Purohit said  two very important concerns need to be borne in mind as India attempts to build herd immunity.

First, the elderly have to be protected by isolating them from the young.

He observed that in India where in urban slums or villages, families live together in one room, it would be difficult to separate the old from the young but this needs to be tackled innovatively.

In rural India, the elderly could be encouraged to sleep outdoors. In slums, the percentage of the population over 60 is very small. 'Unlike rich Indians, poor Indians do not live long lives,' he maintained, drawing attention to the sad reality of India.

Second, while going for herd immunity, every attempt must be made to ramp up the country’s health facilities. He added that if the elderly are protected, then the health facilities as they are should be able to handle the small number of younger people who fall ill and ensure their treatment and survival.

Dr Purohit stated that while India tries to build herd immunity, big gatherings must continue to be banned.

'This means cinemas, theatres (multiplexes), malls, gyms and restaurants must stay closed,' the doctor stressed.