The R-number

The R-number

Subject: Science and Technology

Context: The rising ‘R’ factor in eight States, including Himachal Pradesh, Jammu and Kashmir and Mizoram, besides Kerala, continues to be a cause for worry for the health administration

Concept:

• The R-number, a mathematically calculated estimate which measures the number of people who are being infected by an already infected person
• 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.