The Current R Number And Covid-19

The R Number is important in understanding the transmission rate of Covid-19.


The R Number is important in understanding the transmission rate of Covid-19.

The Department of Health (DoH) has published the current Covid-19 reproduction number (R).

The current estimate of R is 0.6 – 0.9which has remained steady since last week and is helping the Executive in its decision making today.

A spokesperson for the DoH said that as of 21 June, the seven-day rolling average of new cases is two. In the past seven days (from 18 June) there have been four deaths reported.  

It is important to model the Covid-19 epidemic in Northern Ireland in order to plan the delivery of Health and Social Care services and to inform decision making with regard to social distancing and other restrictions.    

Central to this modelling is estimating the Reproduction Number (R). R is the number of individuals who, on average, will be infected by a single infected person.    

There are different ways of calculating R and a number of different values for R each day are produced. That is why the number is being published in the form of banding.

The Executive has indicated that keeping R below 1 is a key objective as we move forward in the epidemic.

However, when community transmission of the virus is very low, R will no longer be the most important number in relation to the status of the epidemic. In particular, once the number of new cases is sufficiently low in the presence of a robust testing programme and test/trace/protect strategy, number of positive tests per day is likely to be a more important measure.  

R is not the only factor which will influence decisions about social distancing and other restrictions. 

It is also necessary to consider the number of cases of Covid-19 and other indicators of the activity of the epidemic, in addition to the benefits which would come from relaxing restrictions.