New Delhi: The effective reproduction number (R) — an indicator of how fast an infection spreads in a population — for Covid-19 in India has decreased slightly to 0.90 from 0.92 last week.
For three weeks now, the R value had remained between 0.90 and 0.92. R must be sustained under 1 for an epidemic to come to an end.
Sitabhra Sinha, a researcher at the Institute of Mathematical Sciences in Chennai, calculated the R values for India and the states with the highest number of active cases.
“Kerala, the no. 1 state currently in terms of active cases, is the only one among the top 16 that has an R value higher than 1. So it looks like the state will continue to hold the top spot next week also,” Sinha told ThePrint.
Barring the first week of January, Kerala’s R value had remained over 1 since 15 December due to a surge in the number of cases. This week, however, the state saw a slight decline in the R value from 1.06 to 1.03.
Over 38 per cent of all active cases in the country are from Kerala. As of Saturday, the state has 70,624 active cases of Covid-19, the highest in the country.
Also read: India’s R value rises slightly to 0.91, infection rate below 1 in major states & cities
States see slight dip in R value
Apart from Kerala, in four of the five states with the highest active caseload, the R values dipped since last week. These four states are Maharashtra, Uttar Pradesh, Karnataka and Chhattisgarh.
The decrease in R values across these states with a high number of active cases explains the overall decline.
Maharashtra, which has the second-highest burden of active cases, saw a sharp decline in its R value to 0.84 this week from 1.08 last week. Uttar Pradesh, the state with the third highest number of active cases, also saw a dip — from 0.90 to 0.82.
Karnataka, which had seen a rise in the R value last week, witnessed a decline from 1.08 to 0.89 this week.
West Bengal was the only state among the five to see a rise in R value — from 0.80 to 0.92 this week.
Of the 16 states whose R values Sinha calculated, Delhi and Rajasthan were the only states that saw an increase in the infection rate.
R values of most major metro cities have remained below 1 this week. Pune, which had recorded an R of 1.11 last week, saw a drop in the value to 0.77 this week.
Also read: India’s Covid R value increases to 0.90, infection rate above 1 in Kerala