Coronavirus / Lockdown can reduce COVID-19 pandemic peak by 43%: ICMR research

New Delhi: A soon-to-be-published mathematical model by the Indian Council of Medical Research (ICMR) suggests that while the 21-day lockdown to check the spread of COVID-19 is expected to bring down daily new cases, instead of extending it, the lockdown needs to be combined with enhanced test-and-quarantine measures.

The study, led by Sandip Mandal of the ICMR’s Department of Health Research, estimates that the current 21-day lockdown will reduce epidemic peak (or the highest number of new COVID-19 cases in a single day) by 43 per cent and total mortality (COVID-19-related deaths) by 19 per cent. And that the lockdown, when combined with an aggressive test-and-quarantine strategy, can bring down epidemic peak by 71 per cent and mortality by 40 per cent.

Mandal was also the lead author of a February mathematical model of the ICMR, which has largely informed the government’s COVID-19 strategy thus far. The February study, conducted by eight scientists, had recommended an approach of quarantine and random testing instead of a focus on border screenings.

Talking to The Indian Express, Mandal said the results of the 21-day lockdown, which began on March 25, are expected to be visible in the next “six to seven days, with a decline in daily new cases”, even though he does believe that there are more positive cases than what is currently being reported.

Calling an extended lockdown “not feasible at all”, Mandal said, “A lockdown is not the final solution to alleviate the epidemic. It reduces peak epidemic but we need additional interventions.”

On the proposed “additional interventions”, he said, “We have to find the hotspots and then try community searching for symptomatic and asymptomatic cases. If incidents like Nizamuddin happen all over India, then we don’t have any control,” he said, adding that it is advisable to have a gradual lifting of the lockdown focused on certain hotspots.

The research team is now modelling the required intensity of a test-and-quarantine strategy (how quickly cases need to be identified and how much quarantine compliance is needed) to prevent a second epidemic.

Reports from other Asian countries such as Singapore, Taiwan and Hong Kong show that a secondary wave of cases is likely to happen after a lockdown is lifted.

The new model assumes “conservatively” that the lockdown reduces transmission by 25 per cent, accounting for incomplete compliance and continued overcrowding in urban settings. “We are also assuming a test-and-quarantine strategy that can identify symptomatic cases within two days of them developing symptoms and a 50 per cent compliance rate with quarantine,” said Mandal, who is also an independent consultant with the World Health Organisation.

The scientist said that even though mathematical models would suggest an extended lockdown — of up to four months — to completely eradicate the COVID-19 spread, “that is not a practical solution”. The 21-day lockdown, he said, was needed to “ensure that the health system can cope with the epidemic and that the peak hospitalisation does not exceed the hospital bed capacity in each city”.