Phased lockdown exit will delay peak in TN by 4 mths, cut cases

Count Would Have Hit 3.5cr Sans Lockdown

Pushpa.Narayan@timesgroup.com

Chennai:6.5.2020

A staggered exit from the lockdown — with strict enforcement of social distancing — will help Tamil Nadu delay the peak by at least four months and pull down the number of cases by nearly half, says a study by researchers at the governmentrun Tamil Nadu Dr MGR Medical University.

The study said Tamil Nadu would have had at least 15,500 cases of Covid-19 on Tuesday compared to the 4,058 cases it registered if the state had not introduced threephases of the lockdown, along with social distancing, mandatory use of masks and hand hygiene.

In a scenario without interventions, the reproductive number (R0) — or the number of people one person will infect — would have been 3.69. That is, every positive person would have infected more than 3 other people. The R0 now is 1.09.

The study has some interesting projections. Without a lockdown, the epidemic would peak in mid-July when there would be 3.5 crore cases at the same time, putting public health facilities under great stress.

A lockdown till the end of June, will delay the peak by four months to October when there would be 1.5 crore cases, which is less than half the non-lockdown peak. And though there would be more cases from mid-September with a lockdown than if there hadn’t been one, the epidemic would have been less devastating.

Overall, there will be far fewer cases with a lockdown and the incidence will also be spread out, with a much lower peak, giving public health authorities the time needed to cope. The lockdown, the study found, brought the R0 to 1.09.

Ideal medical solution to crisis is to extend lockdown: V-C Seshayyan

While the ideal medical solution to this problem will be to extend the lockdown till June, so we can keep the number of people infected at 1.3 lakh. We understand it may not be possible as it can cause huge socio-economic crisis,” said university vicechancellor Dr Sudha Seshayyan, who had sent a note on the analysis to the state health department. In March, the state university was asked to study the effects of the lockdown to help the state formulate strategies based on scientific evidence. It submitted its findings to the state health department on Tuesday.

The lockdown, the study found, brought the R0 to 1.09. “Lifting of lockdown completely will push the R0 to 3.69 once again. This means we will see the number of cases increases once again. This study forecasts when that will happen,” she said.

For instance, if the state decides to exit the third phase of the lockdown on May 17, when researchers forecast 8,437 cases, TN will have 6.2 lakh cases by end of June. “Without the lockdown there could have been 85,718 cases on May 17. But if the state introduces a staggered exist preventing mass gatherings and ensuring stringent public health norms, it is likely to touch 6.2 lakh by June-end” said Dr N Srinivasan, a senior professor, who was also a part of the study.

Even in that case, the university estimates that the state should be able to handle the crisis. So far, 85% of the cases in the state are asymptomatic, while many of the remaining patients rarely report symptoms when they turn up at hospitals. Director of medical education Dr Narayanababu R said while 15% needed intensive monitoring due to age or comorbidities, less than 5% of patients needed interventions such as oxygen. The recovery rate has been nearly 50% and mortality is below 1.1%. “If we keep hospitalisations to the minimum, we should be able to treat most people successfully,” he said.