Novel coronavirus (154) Coronavirus predictions - 80% of population? (6) Coronavirus modelling

18 March, 2020

HIFA colleagues

So, the UK govt has now shifted position and is moving from a mitigation strategy towards one of suppression, with more stringent preventative measures (though still nowhere near enough testing) .

The underlying modelling is presented in the latest (praiseworthily lucid) paper from the Imperial College COVID-19 Response Team

(Report 9: Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand ; available at ).

The Imperial College paper projections for total epidemic deaths - around 90k under the revised strategy announced on 16 March by the UK government (case-isolation, household quarantine and social distancing - reducing further to around 20k deaths if school closures are added) , are considerably better than under the (knowingly unrealistic) do nothing scenario with 80% of GB population infected and 500k deaths . However, even under the preferred strategy the figures are considerably less optimistic than what would be obtained if we managed to approach South Korea's ( or even China’s) epidemic trajectory. In South Korea, a country with a not dissimilar population size to England, the epidemic is (at least currently) levelling off with under 10k cases and under 100 deaths.

Some of this difference will be down to demography - South Korea has relatively young population and coronavirus hits the elderly hardest. But another reason may be that the modelling has explicitly (and understandably) been conservative in estimates of the UK population's voluntary adherence to the announced preventative measures. If these estimates have been too conservative (or if currently voluntary measures become compulsory), the current model may be a good one for the early stages of the epidemic but a poor one for the later stages, if preventative measures began to bite hard. ( In relation to that I note that a key Lancet paper by the same team on the modelling the Wuhan epidemic - Early dynamics of transmission and control of COVID-19:a mathematical modelling study , available at - states that that model predicted at least ten times higher cases than were reported in early February 2020, and that it also did not predict the more recent slowdown in cases, suggesting that transmission might have declined more than in the model.)

Given that, it could be helpful to see - not least as a counterpart to the publicised worst case (do-nothing) modelling - results of modelling a GB best case (do-everything) i.e. an aspirational combination of :

(a) much higher levels of public adherence to the suppression regime

(b) much more extensive infection testing and associated case-isolation and contact tracing

If the results looked good, it could help in sending a more encouraging message to the public about the potential impact of the measures they are being asked to take, demonstrate the big difference a fully co-operative effort could make, stimulate more assiduous testing, and perhaps also offer some comfort to hard-pressed health workers.



Dr Geoff Royston

+44(0)7531 125436

Skype geoff.royston

HIFA profile: Geoff Royston is an Independent Health Analyst and Researcher, former Head of Strategic Analysis and Operational Research in the Department of Health for England, and Past President of the UK Operational Research Society. His work has focused on informing the design, implementation and evaluation of policies and programmes in health and social care, and on fostering the capabilities of others to work in these areas. Associated activities have included modelling for understanding the performance of complex systems, analysis and communication of risk, and horizon scanning and futures thinking. He has also worked on information and communication technology in the health sector, notably in leading the design and national launch of the telephone and online health information and advice service NHS Direct. He has served on both scientific and medical UK Research Council panels, and as an impact assessor for the UK higher education Research Excellence Framework. He is a member of the editorial board for the journal Health Care Management Science and in 2012 was Guest Editor for its special issue on Global Health. He has been a consultant for the World Health Organisation, is a long standing member of the EURO Working Group on Operational Research Applied to Health Services, and is an expert adviser to the mHIFA (mobile Healthcare Information for All) programme. He is also a member of the main HIFA Steering Group and the HIFA working group on Evaluating the Impact of Healthcare Information.

geoff.royston AT