A government projection has been made of of how coronavirus cases in the country can grow rapidly. The report, by the journal of Indian Council of Medical Research or ICMR, says it "may be possible to interrupt the transmission of COVID-19 in India, but only in the most optimistic scenario".
In this scenario, symptomatic cases would be about 1.5 million in Delhi, with roughly 500,000 each in Mumbai, Kolkata and Bengaluru. This would peak over a period of 200 days, beginning February, says the report dated February 27, 2020.
Dr Tarun Bhatnagar, one of the authors of the report and is a Senior Scientist at ICMR's National Institute of Epidemiology in Chennai, told NDTV that India's current fatality rate is around 2%.
If it is possible to home quarantine even 50% of the symptomatic cases then it would be possible to reduce the peak prevalence of cases by 80% to 90%.
"The focus of this mathematical model was to look at the impact of certain intervention measures like home quarantine and airport screening," he said.
"For this mathematical model we used several epidemiological parameters like natural history of infection and travelling between cities and countries. We need not focus on numbers like 1.5 million and 10 million because these numbers were based on earlier stage of the epidemic. We started the study in early February, when numbers were concentrated in China. We have stated in the study that these numbers are hypothetical numbers at this point," he said.
The focus now, he said, needs to be on impact of intervention.
"Before we started this paper, there were international research that said airport screening would be effective for about 50% people. We got a similar number -- that for 46% passengers, airport screening would be ineffective as they would be asymptomatic," he said.
The rapid testing at airport might detect even asymptomatic cases, but that isn't happening at any global airport either since such kits are not available right now.
"We are working on such kits. They are in the pipeline," Dr Bhatnagar said.
He added that home quarantine of symptomatic people was essential as 80% of all cases would be mild symptom cases and only 20% cases would be moderate to severe. Cases that show severe symptoms would be around 4 to 5 per cent.
If India can home quarantine even 50 per cent of the symptomatic people, then it is possible to reduce the number of cases by 62 per cent.
During any epidemic there is a peak. That peak occurance of cases can also be reduced by 89 per cent, he said.
"Going by current scenario and looking at our epidemic curve and number of cases every day, we are kind of in a similar situation as Italy in its early stage," Dr Bhatnagar said.
If India applies the new evolving parameters -- and the case fatality is roughly about 2 per cent in the country right now -- applying the current number of cases to the mathematical model would definitely change numbers, he said.
But the impact of the intervention, that is not going to change much. So the country would still see 50 to 60 per cent reduction in the total number of cases.
If 50 per cent symptomatics are home quarantined, then 80 to 90 per cent reduction in the peak prevalence of cases will take place.
"The government has put in lockdown measures really well to home quarantine people. We have done that quite early in the epidemic and that is our learning from other countries and global epidemic. We will see the impact of the lockdown in a week or two from now, because right now we will still be seeing cases that are a result of those who got infected before the lockdown came," he added.