Contact tracing is an imperfect tool for controlling COVID-19 transmission and relies on population adherence
Emma L. Davis, Tim Lucas, Anna Borlase, Timothy M. Pollington, Sam Abbott, Diepreye Ayabina, Thomas Crellen, Joel Hellewell, Li Pi, CMMID COVID-19 Working Group, Rachel Lowe, Akira Endo, Nicholas G. Davies, Georgia R. Gore‐Langton, Timothy Russell, Nikos I Bosse, Matthew Quaife, Adam J. Kucharski, Emily Nightingale, Carl A. B. Pearson, Hamish Gibbs, Kathleen O’Reilly, Thibaut Jombart, Eleanor M. Rees, Arminder Deol, Stéphane Hué, Megan Auzenbergs, Rein M G J Houben, Sebastian Funk, Yang Li, Fiona Sun, Kiesha Prem, Billy J. Quilty, Julian Villabona-Arenas, Rosanna C. Barnard, David Hodgson, Anna M. Foss, Christopher I Jarvis, Sophie Meakin, Rosalind M. Eggo, Kaja Abbas, Kevin van Zandvoort, Jon C. Emery, Damien C. Tully, Frank Sandmann, W. John Edmunds, Amy Gimma, Gwen Knight, James D Munday, Charlie Diamond, Mark Jit, Quentin J. Leclerc, Alicia Roselló, Yung-Wai Desmond Chan, David Simons, Sam Clifford, Stefan Flasche, Simon R. Procter, Katherine E. Atkins, Graham F. Medley, T. Déirdre Hollingsworth, Petra Klepac
Abstract
Emerging evidence suggests that contact tracing has had limited success in the UK in reducing the R number across the COVID-19 pandemic. We investigate potential pitfalls and areas for improvement by extending an existing branching process contact tracing model, adding diagnostic testing and refining parameter estimates. Our results demonstrate that reporting and adherence are the most important predictors of programme impact but tracing coverage and speed plus diagnostic sensitivity also play an important role. We conclude that well-implemented contact tracing could bring small but potentially important benefits to controlling and preventing outbreaks, providing up to a 15% reduction in R. We reaffirm that contact tracing is not currently appropriate as the sole control measure.