Covid-19 Reproduction Number – R

Date published: 04 June 2020

The Department of Health now publishes the current covid-19 reproduction number (R) on Thursday each week.


The current estimate of R is 0.7 – 0.9 enabling the Executive decision today to ease some restrictions. 

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 person with the infection.  R does not have a fixed value and varies with time.  It is likely to be different every day.

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.

When R is above 1, the transmission of the epidemic will increase, resulting in more cases, hospital admissions and deaths.  The greater the value of R above 1, the more rapid the increase.  When R is below 1, there will be a fall in the number of cases, hospital admissions and deaths.   The further R is below 1, the more rapid the fall will be.  

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

Notes to editors: 

  1. 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. 
  2. For media enquiries please contact DoH Press Office by email:
  3. Follow us on twitter @healthdpt.
  4. The Executive Information Service operates an out of hours service for media enquiries between 1800hrs and 0800hrs Monday to Friday and at weekends and public holidays. The duty press officer can be contacted on 028 9037 8110.

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