New Delhi: India’s effective reproduction number (R) for Covid – an indicator of how quickly the infection is spreading – has steadily increased from a record low of 0.55 to 0.77 over the last month.
Although the overall R remains under 1, indicating that the number of active cases continues to decline, the rate of this decline has slowed down. R should be contained below 1 for the pandemic to come to an end.
“It seems that the rate of decline in active cases has become a lot less recently, so the R has gone up from the historically low values recorded last month,” Sitabhra Sinha, a researcher at the Institute of Mathematical Sciences, told ThePrint.
Sinha, who has been tracking R for India since the beginning of the pandemic, said there are a couple of points to worry about the slowdown.
Assam’s R has been very close to 1 for the last few weeks, indicating that the number of cases may be increasing slowly. The R value of the state, which was at 0.85 around 28 February, has now surged to 0.99.
Uttarakhand has shown a series of very sharp spikes over the last few weeks.
Kerala and Maharashtra, which had the highest burden of infections in the past Covid waves, were also seeing small increases in R values. Kerala’s R value rose from 0.54 to 0.83 over the last one month, while Maharashtra’s R went up from 0.59 to 0.88 during the same period.
The R value in Karnataka has risen to 0.83 from 0.49 last month. West Bengal is another state where R has surged from 0.36 to 0.74.
Major cities
Covid cases have been gradually increasing in the most of the big cities, with Pune being an exception. While Delhi’s R value is at 0.70, Bengaluru and Kolkata have R at 0.90.
“This suggests that somehow in the cities, disease spreading is happening at a sufficiently high rate that the active cases are not declining,” he added.
In Bengaluru, which reported R of 0.64 at the end of February, the numbers have now increased to 0.90. Mumbai’s R has risen to 0.98 from 0.88 last month. Kolkata has also seen a climb in its R value – from a record low of 0.32 last month to 0.90.
Pune is the only city where R has reduced from 0.66 to 0.59.
“The emergence of a new strain that can evade existing immune responses can lead to a possible resurgence of the epidemic,” Sinha warned.
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