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expert reaction to the latest estimate of R and growth rates

The government have released the latest estimate s for the COVID-19 R value in the UK.


Dr Yuliya Kyrychko, Reader in Mathematics, University of Sussex, said:

“The growth rates have remained largely the same, but we have to be careful here: as the number of confirmed cases becomes smaller, the estimates of the growth rate and the R number become more sensitive in a sense that even a relatively small local outbreak can have a major effect on increasing the R number. 

“In this respect, although R number is important, it is crucial to have a detailed breakdown of cases at much finer geographic scale, so that community transmission can be quickly identified and contained. 

“As the lockdown restrictions are being lifted, it may take four to six weeks to see the full effect of this on the number of cases in each geographic area. 

“Opening of pubs on Saturday is, perhaps, the biggest change in terms of social interactions since the lockdown was introduced in March, and since the infection is still prevalent, it is essential to follow the guidelines on how to minimise the risk of acquiring and spreading the infection.”


Dr Konstantin Blyuss, Reader in Mathematics, University of Sussex, said:

“With uncertainty associated with the estimates of growth rates and the R number, and a known and large variability in regional R values at the scale of towns/cities/counties, even if the values of R are estimated to be 0.7-0.9, this does not mean that there cannot be a local growth of infection, and similarly, estimates of 0.9-1.1 do not automatically imply that the outbreak is imminent. 

“The fact that there are almost no changes in these estimates since last week appear to suggest that the level of infection in the UK is plateauing rather than reducing. 

“Recent data from several states in the US seem to indicate that even in those of them, where the infection was already not growing, close contacts in pubs, bars and clubs have resulted in record numbers of infection among the younger population that have even superseded levels seen earlier in the epidemic. 

“This highlights the importance of maintaining social distancing and other protective measures, as the lockdown is being lifted.”


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