Perhaps our most significant conclusion is that mitigation is unlikely to be feasible without emergency
surge capacity limits of the UK and US healthcare systems being exceeded many times over. In the
most effective mitigation strategy examined, which leads to a single, relatively short epidemic (case
isolation, household quarantine and social distancing of the elderly), the surge limits for both general
ward and ICU beds would be exceeded by at least 8-fold under the more optimistic scenario for critical
care requirements that we examined. In addition, even if all patients were able to be treated, we
predict there would still be in the order of 250,000 deaths in GB, and 1.1-1.2 million in the US.
In the UK, this conclusion has only been reached in the last few days, with the refinement of estimates
of likely ICU demand due to COVID-19 based on experience in Italy and the UK (previous planning
estimates assumed half the demand now estimated) and with the NHS providing increasing certainty
around the limits of hospital surge capacity.
We therefore conclude that epidemic suppression is the only viable strategy at the current time. The
social and economic effects of the measures which are needed to achieve this policy goal will be
profound. Many countries have adopted such measures already, but even those countries at an earlier
stage of their epidemic (such as the UK) will need to do so imminently.