India’s R value increases above 1 for first time in 3 months, says researcher

India’s effective reproduction number (R) for Covid, an indicator of how quickly the infection is spreading, has increased to over one for the first time since January, estimates a researcher from Chennai’s Institute of Mathematical Sciences.

The country’s R value, steadily increasing over the last few weeks, is 1.07 for the week between April 12-18, according to Sitabhra Sinha. In the preceding April 5-11 week, it was 0.93. The last time the R was above 1 was in the week between January 16-22, when the value was 1.28, Sinha said.

“This increase in R-value is not just because of Delhi but also Haryana and Uttar Pradesh,” the mathematician, who has been tracking R for India since the beginning of the pandemic, told PTI.

An R value over 1 indicates that the number of active cases has increased. R should be contained below 1 to control the pandemic. An R number lower than 1 indicates that the disease will stop spreading as there aren’t enough people being infected to sustain the outbreak.

The R value this year was highest between January 1-10, reaching 2.98 when the Omicron variant of coronavirus caused the third wave in India. Almost all major cities — Mumbai, Bengaluru and Chennai — are showing R values above 1. In fact, Delhi and Uttar Pradesh have an R value above 2. Data for Kolkata was not available, Sinha said.

The estimated R value in the week ending April 18 is 2.12 for Delhi, 2.12 for Uttar Pradesh, 1.04 for Karnataka, 1.70 for Haryana, 1.13 for Mumbai, 1.18 for Chennai and 1.04 for Bengaluru. Among the major states, Kerala and Maharashtra have an R value less than 1, with values of 0.72 and 0.88 respectively.

“Karnataka also has R over 1 currently, possibly because of the rising cases in Bengaluru,” Sinha explained. With 2,067 new coronavirus infections being reported in a day, India’s total tally of COVID-19 cases rose to 4,30,47,594 (4.3 crore) while active cases increased to 12,340, according to the Union Health Ministry data updated on Wednesday.

An increase of 480 cases has been recorded in the active COVID-19 caseload in a span of 24 hours. The daily positivity rate was recorded at 0.49 per cent and the weekly positivity rate was recorded at 0.38 per cent, according to the health ministry.

On Tuesday, Delhi recorded a nearly 26 per cent jump in fresh Covid cases but positivity rate dropped to 4.42 per cent, according to data shared by the city health department on Tuesday. While 632 fresh Covid cases were reported in Delhi, the positivity rate was 4.42 per cent. The city had on Monday recorded 501 cases and zero death while the positivity rate stood at 7.72 per cent.