  It is evident that increasing the intensive-care-unit (ICU) capacity and
giving priority to admitting and treating younger patients will reduce the
number of COVID-19 deaths, but a quantitative assessment of these measures has
remained inadequate. We develop a comprehensive, non-Markovian state transition
model, which is validated through accurate prediction of the daily death toll
for two epicenters: Wuhan, China and Lombardy, Italy. The model enables
prediction of COVID-19 deaths in various scenarios. For example, if treatment
priorities had been given to younger patients, the death toll in Wuhan and
Lombardy would have been reduced by 10.4\% and 6.7\%, respectively. The
strategy depends on the epidemic scale and is more effective in countries with
a younger population structure. Analyses of data from China, South Korea,
Italy, and Spain suggest that countries with less per capita ICU medical
resources should implement this strategy in the early stage of the pandemic to
reduce mortalities.
