Covid Explained: What Is ‘R’ Factor? All You Need To Know

The R-factor or reproduction rate, indicates the speed at which the Covid infection is spreading in the country. It is the mathematical representation that acts as an indicator for how fast the infection is spreading. 

Why is it a matter of concern now?

According to a PTI report, researchers at the Chennai-based Institute of Mathematical Sciences (IMSc) revealed that the R-value for coronavirus has gone up for the country.  Their analysis revealed that it has gone from 0.78 on June 30 to 0.88 in the first week of July. This is despite the nationwide tally of new cases remaining low. 

What is the cause of worry?

This analysis has added to the worries and concerns about the pandemic as it comes amid the unlocking process by many states trying to restore a semblance of normalcy as the deadly second wave, which infected lakhs and killed thousands during its peak in April-May, shows signs of ebbing.

Sitabhra Sinha, who led the team of researchers said the ‘R’ for India is still below one, so the number of active cases is decreasing at a much slower rate. The same trend of slowing down in the rate of decline in active cases is also seen in many states.

“Kerala showed a brief spike in cases and its R continues to hover close to 1. The northeast region is of great concern. Manipur, Arunachal Pradesh and possibly Tripura are showing a rise in the number of cases,” Sinha pointed out.

What does the analysis say?

When the second wave of the coronavirus infection was at its peak, the overall R-value in the country was estimated to be 1.37 between March 9 and April 21. It declined to 1.18 between April 24 and May 1 and then to 1.10 between April 29 and May 7, according to the analysis.

Between May 9 and 11, the R-value was estimated to be around 0.98. It then came down to 0.82 from May 14 to May 30. The R-value was 0.78 from May 15 to June 26 and 0.88 from June 20 to July 7.

In Kerala, the R-value is estimated to be around 1.10. As for the northeastern states, the R for Manipur is 1.07, Meghalaya 0.92, Tripura 1.15, Mizoram 0.86, Arunachal Pradesh 1.14, Sikkim 0.88, Assam 0.86.

Rising Covid-19 cases in Kerala, coupled with the recent outbreak of the Zika virus, is a matter of concern for the health authorities as the southern state battles to bring down daily new infections.

What does the change in R value mean now?

“India’s R has increased a bit to 0.88 from June-end after being at the lowest ever value of 0.78 (since the pandemic began in March last year) from mid-May till late last month,” PTI quoted Sinha.

This means, every 100 infected people on average pass on the infection to 88 other individuals. If R is lesser than 1, it means the number of newly infected people is lower than the number of infected people in the preceding period which means the disease incidence is going down, the lead researcher said.

“The smaller the value of R is, the faster the disease is on decline. Conversely, if R is greater than 1, the number of infected people is increasing in each round—technically, this is what we call the epidemic phase. The bigger the number is than 1, the faster the rate of spreading of the disease in the population,” Sinha added.

On Tuesday, PM Modi urged people not to compromise on Covid protocols to prevent a third wave of coronavirus.

With PTI inputs