COVID-19 spread isn't exponential in India, next three days crucial: Medical researchers

The nationwide lockdown has helped cut down the spread of COVID-19 into the community, as the number of infected patients hasn't risen exponentially so far unlike the USA or Europe, but the next three days are crucial, medical researchers said on Tuesday.

"You have to wait for three more days before you can say India is low. The real test will be the slums of Dharavi. Will Dharavi explode or not? If Dharavi doesn't explode, we can say that the hygiene hypothesis (If a place is dirty, people living there automatically develop immunity) is working" Samir K Brahmachari, former director-general of the Council for Scientific and Industrial Research told DH.

The three-week-long lockdown is scheduled to end on April 14. At the moment, there's no clarity whether it would be extended.

"The trend in India follows a relatively flat curve and it doesn't in any way resemble that of the European countries or the USA," added N Devadasan, former director of the Institute of Public Health, Bengaluru.

The reasons, the researchers hypothesised, could vary from warmer climate and inherent immunity among the Indians to the initial screening system to pick up international travellers with symptoms and put their friends and families under surveillance to curb the virus's spread.

However, there's little scientific evidence from the ground as it is early days for India's medical research community to explore all the aspects of the disease dynamics.

For instance, the Indian Council of Medical Research currently restricts the serology testing to diagnose even though a section of the researchers says that such tests should be also used for studying the baseline prevalence of the infection.

At a time when the central government discusses the possibility of extending the lockdown, the researchers admit that the pan-Indian closure has helped slow down the virus' march into the community.

"The current lockdown is effective though it was diluted with the mass movement of migrant workers to their home states. The government should have anticipated this and taken measures to either prevent or manage it. There were some minor leakages, but in general, it may have achieved its objective of cutting down transmission," said Devdasan, Technical Adviser, Health Systems Transformation Platform.

"Social distancing is definitely working, otherwise the numbers would have increased by around 2,000 per day," said Brahmachari.

A study (not peer-reviewed) by two scholars at Shiv Nadar University also establishes the efficacy of the lockdown.

"In an optimistic scenario in which 80−90% of population contributes to social distancing the projected number of symptomatic cases can decline by nearly 85% at day 20 from the beginning of the lockdown (3,500 against 30,790) and deaths (105 against 619) as well. Thus, intervention (20-day lockdown) may help in slowing transmission and flattening the COVID-19 curve," said Samit Bhattacharyya and Naga Suresh Veerapu from Shiv Nadar University in a statement.