Given the size of India's population, coronavirus testing needs to be scaled up in a manner that can be sustained, Union Health Minister Harsh Vardhan has said, noting that the lockdown and social distancing are the most effective 'social vaccines' available to fight the pandemic.

At the same time Vardhan, in an interview to The Week magazine, dispelled concerns that India might be testing fewer people than required and said the testing has been extended in a manner to prioritise individuals who are primarily at risk of the infection.

As of April 8, a total of 1,04,764 tests were carried out in India, he said, adding the present capacity of testing is 20,000 per day.

On the issue of paucity of ventilators, the health minister, citing official data, said that 80 per cent of the infections are mild or asymptomatic, 15 per cent are severe requiring oxygen, and only 5 per cent patients under critical category require ventilation.

He said around 17,000 ventilators are available for the virus-infected people while another 48,538 units are being procured in the coming weeks.

On the availability of personal protective equipment (PPEs), Vardhan said it has been a worldwide problem and is more acute in India because they were not manufactured locally. He said a total of 1.57 crore PPEs are being procured.

Talking about the overall trend of coronavirus infection, Vardhan said more than 80 per cent of the cases were reported from 71 districts across 17 states.

It is vital that community-led interventions to ensure social distancing, quarantining and isolation of symptomatic persons are initiated to augment the scale of the lockdown in place, he said.

Everything depends on the people and their discipline to strictly follow all public health measures being outlined, Vardhan said, cautioning that any single break in the chain can prove counterproductive.

'Although the world, including India, is striving hard to develop a vaccine for COVID-19, I strongly feel that lockdown and social distancing are currently the most effective 'social vaccines' available to the masses,' he said.

India went under a 21-day nationwide lockdown on midnight of March 24. There have been indications that the central government may extend the lockdown beyond April 14 with some possible relaxations.

'I have coined this term 'social vaccine' for lockdown and social distancing as a combined intervention strategy to not only contain, but also mitigate this dreadful pandemic,' Vardhan said.

He said the upcoming few days will be critical for India in the fight against the pandemic.

'The experience, as is evident from the global response, tells us that even with stringent lockdowns and public health measures in place, the transmission dynamics of COVID-19 are such that it takes about two to four weeks to bend the curve,' he said.

The death toll due to the novel coronavirus in India has risen to at least 239 and the number of cases to at least 7,447, according to the Union Health Ministry.

On the hotspots identified to check spread of the virus, Vardhan said 'community ownership', especially for social distancing, remains the most important intervention.

In districts with more than 15 cases, an action plan for containment of large outbreaks is being followed, he said.

'There are 76 districts with fewer than 15 cases each, where we are following an action plan for cluster containment,' Vardhan said.

The minister also hailed the efforts by the states in dealing with the crisis, saying they were doing well and responding to the Centre's call.

There are some exemplary 'best practices' by the states, Vardhan said.

Elaborating on the government's efforts to scale up testing for COVID-19, he said that given the population of India, testing needs to be scaled up in a manner that can be sustained while building up capacity for testing and management of positive cases.

'With the impending scaling up of testing, it is envisioned that we shall reach optimal levels of case detection. In addition, we are also considering scaling up of rapid antibody tests, which is easier to do and takes less time, but is not recommended as a diagnostic test,' he said.

He said the current iteration of the testing strategy is customised based on the transmission typology in India.

'The testing has been extended in a manner to prioritise individuals who are primarily at risk. Given the population of India, we need to scale up in a manner that can be sustained while we build up capacity for testing and management of positive cases,' he said.

At present, 136 government labs and 59 NABL-accredited (National Accreditation Board for Testing and Calibration Laboratories) private laboratory chains are involved in testing.

'We are making sure that the quality of the testing kits and the biosafety of the testing labs are maintained so as to avoid any issues related to unreliable results or iatrogenic transmission (illness caused by medical examination or treatment) in health care or laboratory staff,' the minister said.

He said there is also a possibility in the long term that the coronavirus will get mix in with the seasonal flu virus, and have seasonal trends, much in line with the current influenza patterns.

'Finally, there is also the consideration that like the 2003 pandemic of SARS, this new infection will also fizzle out and eventually die out,' he said.

The development of vaccines and therapeutics is also likely to impact the way the infection plays out in the long term, Vardhan added.

'For now, we need to focus on limiting the deaths and raising a concerted effort to reduce the impact of COVID-19 in India,' he said.

On PPEs, he said all potential manufacturers based in India were contacted and provided handholding support to make good-quality PPEs.

The health ministry, along with the external affairs ministry and the textiles ministry, has identified several other foreign sources.

'As of now, hospitals across the country have around 4 lakh PPEs with them. We are aiming to achieve 10 lakh a week by the end of next week,' Vardhan said.

He also said that private sector players have a major role to play in responding to this national crisis and they have helped scale up the testing capacity in the country.

Talking about the future course in terms of progression of the disease, Vardhan said there are several theories that explain the future progression of COVID-19, but it was not clear which of them will eventually play out.

'In the short term, this is likely to play out like an epidemic, which inevitably follows a pattern of going up and then coming down to a baseline, over three to six months, depending on the intensity of interventions put in place,' he said.

If herd immunity develops in the community, there is a possibility that the infection will fizzle out in the medium term, over the next few months, he said.