Estimates of regional infectivity of COVID-19 in the United Kingdom following imposition of social distancing measures

This article is part of the theme issue ‘Modelling that shaped the early COVID-19 pandemic response in the UK'.
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reproduction number has become an essential parameter for monitoring disease transmission across settings and guiding interventions. The UK published weekly estimates of the reproduction number in the UK starting in May 2020 which are formed from multiple independent estimates. In this paper, we describe methods used to estimate the time-varying SARS-CoV-2 reproduction number for the UK. We used multiple data sources and estimated a serial interval distribution from published studies. We describe regional variability and how estimates evolved during the early phases of the outbreak, until the relaxing of social distancing measures began to be introduced in early July. Our analysis is able to guide localized control and provides a longitudinal example of applying these methods over long timescales.
Support for R.C. and K.T.A.'s research is provided by the EPSRC via grant no. EP/N014391/1; R.C. is also funded by TSFT as part of the NHS Global Digital Exemplar programme (GDE); there were no financial relationships with any organizations that might have an interest in the submitted work in the previous 3 years, no other relationships or activities that could appear to have influenced the submitted work. L.D. and K.T.A. gratefully acknowledge the financial support of The Alan Turing Institute under the EPSRC grant no. EP/N510129/1. L.L. acknowledges the financial support of the EPSRC via Early Career Fellowship EP/P01660X/1. L.D. and E.B.P. are supported by Medical Research Council (MRC) (MC/PC/19067). E.B.P. was partly supported by the NIHR Health Protection Research Unit in Behavioural Science and Evaluation at University of Bristol, in partnership with PHE.