Loading...

Preprints

Global predictions of short- to medium-term COVID-19 transmission trends : a retrospective assessment

Bhatia S, Parag K, Wardle J, Imai N, Elsland Sv, Lassmann B, Cuomo-Dannenburg G, Jauneikaite E, Unwin HJ, Riley S, Ferguson N, Donnelly C, Cori A, Nouvellet P.
Preprint from
Research Square
13 August 2021
PPR
PPR382578
Abstract
From 8th March to 29th November 2020, we produced weekly estimates of SARS-CoV-2 transmissibility and forecasts of deaths due to COVID-19 for 81 countries with evidence of sustained transmission. We also developed a novel heuristic to combine weekly estimates of transmissibility to produce forecasts over a 4-week horizon. We evaluated the robustness of the forecasts using relative error, coverage probability, and comparisons with null models. During the 39-week period covered by this study, both the short- and medium-term forecasts captured well the epidemic trajectory across different waves of COVID-19 infections with small relative errors over the forecast horizon. The model was well calibrated with 56.3\% and 45.6\% of the observations lying in the 50\% Credible Interval in 1-week and 4-week ahead forecasts respectively. We could accurately characterise the overall phase of the epidemic up to 4-weeks ahead in 84.9\% of country-days. The medium-term forecasts can be used in conjunction with the short-term forecasts of COVID-19 mortality as a useful planning tool as countries continue to relax public health measures.