Covid-19: The state of R in India

The effective R number takes into account factors relating to how the virus jumps from person to person (for instance, the basic infectivity if the virus, the probability of an actual infection during contact, and the duration of contagiousness.)

Every two people in India infected with the SARS-CoV-2 virus, on average, pass on the coronavirus (Covid-19) to at least three more people. This estimation is based on an epidemiological parameter known as the effective reproduction number, or R(t), which for India at the moment is estimated to be around 1.5-1.6.

A health worker collects a swab sample for coronavirus test, at Nizamuddin Railway Station, in New Delhi, India. (Amal KS/HT Photo)

The effective R number takes into account factors relating to how the virus jumps from person to person (for instance, the basic infectivity of the virus, the probability of an actual infection during contact, and the duration of contagiousness.) How this number varies across states not only reflects how serious an outbreak may have become but it can also help predict emerging hot spots.