Comparing the responses of the UK, Sweden and Denmark to COVID-19 using counterfactual modelling

Abstract

The UK and Sweden have among the worst per-capita COVID-19 mortality in Europe. Sweden stands out for its greater reliance on voluntary, rather than mandatory, control measures. We explore how the timing and effectiveness of control measures in the UK, Sweden and Denmark shaped COVID-19 mortality in each country, using a counterfactual assessment: what would the impact have been, had each country adopted the others’ policies? Using a Bayesian semi-mechanistic model without prior assumptions on the mechanism or effectiveness of interventions, we estimate the time-varying reproduction number for the UK, Sweden and Denmark from daily mortality data. We use two approaches to evaluate counterfactuals which transpose the transmission profile from one country onto another, in each country’s first wave from 13th March (when stringent interventions began) until 1st July 2020. UK mortality would have approximately doubled had Swedish policy been adopted, while Swedish mortality would have more than halved had Sweden adopted UK or Danish strategies. Danish policies were most effective, although differences between the UK and Denmark were significant for one counterfactual approach only. Our analysis shows that small changes in the timing or effectiveness of interventions have disproportionately large effects on total mortality within a rapidly growing epidemic.

Community factors and excess mortality in the COVID-19 pandemic in England, Italy and Sweden

“…28 This was not the case for England or Sweden where the disease spread later and more evenly. 29 Secondly, because spatial units in Italy are based solely on administrative area, resulting in more diverse population sizes, with large metropolitan areas (such as Rome or Milan) aside small rural towns or villages. This also contributed to the high percentage of variance explained by local clustering (Table 3) for Italy.…”

Vaccinations or Non-Pharmaceutical Interventions: Safe Reopening of Schools in England

“…Minimal simulated increases in the reproduction number due to school opening have also been found in studies from Norway 38 and Japan 39 . However, comparison of the resuse of NPIs in different countries suggest the same intervention in one country can have very different outcomes in others 40 . For the UK Sonabend et al 20 use a compartmental transmission model 41 and include the effect of VOC and a sterilising vaccine to explore a range of scenarios for relaxing restrictions from the period June -August 2021 20 .…”

Vaccinations or Non-Pharmaceutical Interventions: Safe Reopening of Schools in England

“…Minimal simulated increases in the reproduction number due to school opening have also been found in studies from Norway 35 and Japan 36 . However, comparison of the resuse of NPIs in different countries suggest the same intervention in one country can have very different outcomes in others 37 . For the UK Sonabend et al 18 use a compartmental transmission model 38 and include the effect of VOC and a sterilising vaccine to explore a range of scenarios for relaxing restrictions from the period June -August 2021 18 .…”