All about the curve: Experts on whether India will be able to flatten the COVID-19 curve effectively

There have always been differing opinions on curves: some like it, some don't. But as the novel coronavirus pandemic continues to haunt the world, a curve has become the centre of most conversations around measures to contain the spread of COVID-19. 

What is this curve?

India is currently under a 21-day lockdown, people have been asked to practice strict social distancing and go out only for essential activities - all because of this curve. 

Called an epidemic curve, or ‘epi’ curve, It shows a hypothetical number of cases in a pandemic over time without an intervention and with an intervention. The dotted line represents the capacity of the hospitals and our healthcare systems. 

If we didn't take the measures like social distancing and the lockdown, it'd be like the case in the first epi curve. The one with the steep peak indicating a surge of coronavirus outbreak in the near term.   

If we took those measures, then the number of cases could pan out as in the second epi cruve. The one with a flatter slope, indicating a more gradual rate of infection over a longer period of time.  

How is India doing?

On March 29th, Shamika Ravi, the Director of Research at Brookings India and a former member of PM's Economic Advisory Council, said that the growth rate of confirmed cases began declining in India from March 23rd - hinting at a possibility of the curve starting to flatten. She attributed this slight decline to India's policy decisions 10-14 days prior to March 23rd. She said, "if you go back to March 13, the imposition of large-scale travel ban from several hotspot countries, the shutting down of schools and colleges, and some states invoking the Epidemic Diseases Act, contributed to the beginning of flattening of the curve. 

"People must realise that the actual numbers will continue to rise. But if we look at the graph, pre-March 23rd, the confirmed number of cases was doubling every 3 days. March 23rd onwards that growth rate has declined to doubling in every 5 days. And since we know that this virus has an incubation period of 10-14 days, the slight flattening can be traced back to the policy decisions made roughly 10 days prior," Ravi added. 

The ministry of health and family elfare (MoHFW) too made similar claims of Monday when they said India went from 100 cases to 1,000 cases in 12 days. In comparison, Covid-19 cases in other developed countries rose between 3,500 and 8,000 in the same time frame.

“These are all developed nations and the population is less than India,” joint secretary (health) Lav Agarwal said. “We have been able to restrict the number of cases because of our social distancing norms followed by the people and the pre-emptive approach of government."

Then why's there a spike recently?

The number of confirmed covid-19 cases in India rose by 17 percent in 12 hours to reach 1,251 Monday evening, the latest data from the MoHFW shows. The number of active cases rose 18 percent over the same period to 1,117.

Shamika Ravi tweeted on Tuesday morning talking about a "reversal of fortunes" due to violations of social distancing measures in the recent past. Her latest graph shows a spike from March 29. She attributes this partially to the Tablighi Jamaat event held in early-March at the Nizamuddin mosque in Delhi. 

Despite Delhi government's order against congregation of more than 50 people, more than 3,400, including people from Malaysia and Indonesia gathered at Nizamuddin Markaz. 

About 1,500 people remained there until recently. Now, at least 10 COVID-19 deaths across the country have been traced back to this congregation and close to 50 attendees have tested positive for novel coronavirus.  

Ravi says that the effects of this "fiasco have shown up after 10-14 days".

Along with this, we have seen how the lockdown has triggered mass gatherings and exodus of the migrant labourers - flouting the prescribed social distancing norms. 

Read/listen: A Tale of the Long Walk Home

Mass congregations like this carry the risk of spreading COVID-19 even further, says Oommen C. Kurian, head of the health initiative at the Observer Research Foundation, an independent think-tank based in New Delhi. He worries that migrants might carry the virus to rural areas, where health infrastructure is weak, or even non-existent.

Can India flatten the curve?

As of March 30, India has reported more than 1,200 cases of COVID-19. Given its densely populated cities, experts worry that the country’s fragile health system will not be able to adequately respond to a spike in cases. Thus flattening the curve becomes one of the only options we have.

So far, India has administered more than 38,000 tests. While the country initially faced criticism for its low testing numbers, the number of tests has been ramped up in the days following the lockdown. Experts say India should use the time bought by the lockdown to test more and find and contain hotspots.

Another rising concern has been whether the lockdown will be enough to flatten the curve. The government said on Monday that it has no plans of extending the lockdown beyond April 14, amid concerns over how the livelihoods of millions of poor migrant labourers and wage workers have been disrupted.

What happens to the curve after the lockdown is lifted? 

Researchers at the Cambridge University, Rajesh Singh and Ronojoy Adhikari, have said that the "21-day lockdown will not work" in their paper 'Age-structured impact of social distancing on the COVID-19 epidemic in India'.

They use a mathematical model based on country-specific age and social contact distributions to recommend a longer lockdown interrupted by periods of relaxation instead.

"The epidemic is always a little ahead of us. For one day of growth, we need more than one day of lockdown to bring infections down to starting levels. Extending this, we can see why the 21-day lockdown will not work. The epidemic has had much more than 21 days to grow," says Ronojoy Adhikari. 

According to their study, even a strict measure like the nationwide lockdown won't be enough the flatten the curve to ground, instead their model predicts an eventual rise in the curve. 

Extensive social distancing, testing and quarantining can do the trick

So we don't have many options but to ramp up our testing to extensive levels. As the World Health Organisation (WHO) lays special emphasis on steps like testing, quarantine and treatment -- it says extensive social distancing measures like lockdowns only buy countries time to "attack the virus" so it doesn't come roaring back once restrictions are lifted.

"Aggressive measures to find, isolate, test, treat and trace are not only the best and fastest way out of extreme social and economic restrictions," said WHO director-general Tedros Adhanom Ghebreyesus on March 25, the day after India enforced its 21-day lockdown.