Coronavirus recovery curve aligned with case rate, with a 2-week lag

The high recovery rate, however, does not take into account the severity of the disease during the recovery process.

Read | Over the last week, slight but ‘noticeable’ flattening of growth curve in coronavirus cases

The Indian Express had reported on April 8 that mapping the global number of COVID-19 patients who recovered largely mimics the global case load, with a 14-day lag. However, since then, the global recovery rate has begun to fall flat, while cases worldwide continue to grow exponentially.

In order to make the global comparison, this examination used data from the Johns Hopkins University database.

When asked about the India trends, Sitabhra Sinha, a scientist at the Institute of Mathematical Sciences in Chennai, said it aligns with other research showing the mortality rate in India is lower than global rates, so far.

Sinha explained that if everyone who fell sick on Day 1 recovered 14 days later, the two curves would exactly align. Any discrepancy between the two lines is either due to people who fell sick and died, or people who recovered earlier or later than the mean period of 14 days. People are as likely to recover earlier as they are later, he said, making these two effects balance each other out.

“So that leaves only accounting for those who died. This is probably why the recovered curve is lower than the infected curve in (the global) figure,” Sinha said.

Globally, there is considerable research on the mortality of COVID-19, there is less literature to help understand the patterns of recovery.

There is no established recovery time of COVID-19 patients. Early World Health Organisation reports from China in late February said mild cases had a recovery time of roughly two weeks, while people with severe cases could take between three to six weeks to recover.

In a WHO briefing in early March, its executive director said a recovery is measured by a patient no longer showing symptoms and having two consecutive negative tests for the virus at least one day apart.

However, countries measure “recovery” differently.

The WHO does not put out global recovery rates, and without uniform methods of reporting recoveries, the number will inevitably be an estimate, according to experts. “Recovered cases outside China are estimates based on local media reports, and may be substantially lower than the true number,” states the Johns Hopkins Dashboard.

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