The academic study from Imperial College which forms the basis of the government's latest coronavirus strategy can be downloaded here. [20 page pdf]
It focuses on whether to adopt a mitigation or suppression strategy, concluding that mitigation would "overwhelm healthcare systems many times over" and "epidemic suppression is the only viable strategy at the current time."
» Mitigation: Here the aim is to use non-pharmaceutical interventions, not to interrupt transmission completely but to reduce the health impact of an epidemic.
» Suppression: Here the aim is to reduce the average number of secondary cases each case generates to below 1, and hence to reduce case numbers to low levels.
• "In the (unlikely) absence of any control measures or spontaneous changes in individual behaviour... we would predict approximately 510,000 deaths in GB."
• "For suppression, early action is important, and interventions need to be in place well before healthcare capacity is overwhelmed."
• "A minimum policy for effective suppression is population-wide social distancing combined with home isolation of cases and school and university closure."
• "Such an intensive policy is predicted to result in a reduction in critical care requirements from a peak approximately 3 weeks after the interventions are introduced and a decline thereafter while the intervention policies remain in place."
• "There are very large uncertainties around the transmission of this virus, the likely effectiveness of different policies and the extent to which the population spontaneously adopts risk reducing behaviours. This means it is difficult to be definitive about the likely initial duration of measures which will be required, except that it will be several months."
• "Once interventions are relaxed, infections begin to rise, resulting in a predicted peak epidemic later in the year. The more successful a strategy is at temporary suppression, the larger the later epidemic is predicted to be."
• "We estimate that for a national GB policy, social distancing would need to be in force for at least 2/3 of the time until a vaccine was available – which could be 18 months or more."
• "The social and economic effects of the measures which are needed to achieve this policy goal will be profound."
