India could see last of new Covid cases by July-end, Singapore study predicts using AI, data

Model doesn't take into account possibility of second wave of infections. Researchers also say estimates may not be accurate for countries under-reporting cases.

File photo| Women health workers during house-to-house drive for coronavirus testing, Kolkata | ANI

New Delhi: India is likely to see the last of the new Covid-19 cases by 26 July, according to a team of researchers from Singapore.

The team from the Singapore University of Technology and Design used an artificial intelligence algorithm to make data-driven predictions of when the Covid-19 pandemic will end in 131 countries.

The predictions were uploaded on the university’s website on 26 April.

According to the predictions, the pandemic is likely to end in the world by 9 December, though some countries, including Bahrain and Qatar, will see the last of its fresh cases in February 2021.

For India, the team predicts that 97 per cent of the total expected cases will be identified by 21 May.

The model

According to the researchers, Covid-19 follows a lifecycle pattern similar to other pandemics. The outbreak has an initial acceleration phase, which witnesses an exponential rise in cases. This is followed by the inflection point — or the point at which the curve begins to flatten. 

This point is followed by a deceleration phase, where the curve begins to dip, eventually bringing the pandemic to an end. 

Researchers explained that the curve responds to counter-strategies of individuals and governments, which include social distancing and lockdowns, along with natural limitations of the ecosystem.

To predict when the pandemic will end for every country, researchers plotted the latest infection data from each country initially and then used the SIR model to predict the curve for each country.

An SIR model computes the number of people that will likely become infected with a contagious illness in a population over a period of time. 

The computation is based on the number of people susceptible to the disease (S), the number of people infected (I) and the number of people who have recovered (R) from the disease.

The predictions provide three alternative estimates of end dates — the date when the last expected case has been identified, the date when 99 per cent of the expected total cases have been identified, and the date when 97 per cent of the expected cases have been identified.

The predictions based on data until 25 April showed that the pandemic is likely to end in the worst-affected countries like the US and Italy by the last week of August, though both countries will identify 97 per cent of the total cases by 12 May and 8 May, respectively. 

Limitations

The researchers, however, advised caution in interpreting the results of the predictions. They said becoming overly optimistic based on some predicted end dates “might be dangerous”. 

Easing existing restrictions can cause the infection rates to change, the researchers pointed out. 

The model also does not take into account the possibility of a second wave of infections.

The quality of the predictions also depends on the quality of the data, the researchers said. This means the estimates may not be accurate for countries that may be under-reporting cases.