Worry has a new variant: R Count of Covid hovering around the key 1 mark

Even as India braces for Omicron, the all-India R count for SARS CoV-2 is already hovering close to the worrying 1 mark.

The R value must be below 1 for active cases to start coming down.

Sitabhra Sinha, professor at the Institute of Mathematical Sciences, has been tracking India's R count closely since the onset of the pandemic and his latest assessment - up to December 2 - shows that the R value for the country is hovering around the 0.95 mark with the states of Telangana, Odisha, Jammu & Kashmir and probably Himachal Pradesh already above 1.

The R value is an important indicator on Covid-19's prevalence and spread as this effective reproduction number Re - sometimes also called Rt - points to the number of people in a population who can be infected by an individual.
Its value decreases as the population becomes increasingly immunized either by individual immunity following infection or by vaccination. It must be below 1 for active cases to come down.

While India hit its high with Covid-19 onset on March 25, 2020 with a R value of a dizzying 3.75, it went below 1 between September 2020 and January/February 2021.

The onset of the second wave in early March changed that dramatically when the R count reached a high of 1.61 - indicating that the infection spread, and rate had increased significantly.

"The R for India has continued to hover around the same value of 0.95 since mid-October...Two other states Kerala and Andhra Pradesh have R just under 1, with the possibility that a chance superspreading event can push it to values above 1. And for some large cities the situation continues to be not so great with all of them intermittently having their R go above 1", Sinha told ET.

Sinha's city analysis shows Mumbai and Pune at R counts of 1.09 and 1.13, respectively, Chennai is hovering at 0.96 and Kolkata is at 0.95 while Delhi is at 0.89 and Bengaluru at 0.88.

"At the moment, Mumbai and Pune both have R value above 1 and have had it ever since early November. Going into the winter, it'd be of interest to see whether a new surge across the country will appear - we were spared this last year fortunately despite fears in many quarters," Sinha pointed out.

Latest data from the University of Michigan's Covid India database puts India's national R count at 0.86 but also shows 13 states and 4 union territories are well above the 1 mark.

This shows the continued active transmission of SARS CoV 2 even before Omicron made its presence felt in India. India's overall count has been in the 0.95 range since mid-October.