Fig. 3.

Representation of sustainable or unsustainable scenarios under combinations of vaccination coverage and population mobility index in epidemic initiated by ancestral strain (A) or its variants including Alpha (B), Beta (C), Gamma (D), Delta (E), and Omicron (F). Using the maximum daily number of hospital admissions and admissions in ICU as a sustainable threshold to maintain the burden in hospital capacity in Hong Kong, scenarios were defined as “unsustainable” if either of two criteria: 1) any 15-day moving averages (Mas) of newly hospital admissions (hereafter, metric A); 2) any 17-day Mas of number of cases in ICU (hereafter, metric B) in the simulated epidemics were larger than the respective sustainable threshold or vice versa.