16 March 2020 Imperial College COVID-19 Response Team 1400 1200 sse1000 a c800 ICUkly 600 ee W 400 200 0 Figure 4: Illustration of adaptive triggering of suppression strategies in GB, for R0=2.2, a policy of all four interventions considered, an “on” trigger of 100 ICU cases in a week and an “off” trigger of 50 ICU cases. The policy is in force approximate 2/3 of the time. Only social distancing and school/university closure are triggered; other policies remain in force throughout. Weekly ICU incidence is shown in orange, policy triggering in blue. DOI: https://doi.org/10.25561/77482 Page 12 of 20