R VALUE

Subject: Science & tech

Context: At 0.98, India’s R value drops below 1 for the first time during second Covid wave.

Concept:

R0 or reproduction number tells you the average number of people who will contract a contagious disease from one person with that disease
R-naught is a frequently used mathematical metric to estimate how contagious an infectious disease can be. It can help in making projections for the number of people likely to be affected by such a disease and is often used to decide on the kind of policy interventions required to halt the epidemic.
A less than one value for R-naught would mean that disease would not take the form of an epidemic. Any value more than one indicates an exponential rise in the number of patients.
R-naught is also a dynamic metric, and is sensitive to the kind of interventions made to contain the spread.