CDC研究都是用最大7天的確診案例，住院和死亡。但Omicron比Delta病程短，所以都用最大7天的住院和死亡數量與base（確診病例）比，有可能Omicron被納入的死亡和住院病人比base多。
原文：
The maximum 7-day moving averages of the daily number of COVID-19 cases, ED visits, hospital admissions, and deaths during the Omicron period were compared with the peak 7-day moving averages for the winter 2020–21 and Delta periods. The maximum percentages of inpatient and ICU bed use overall and by COVID-19 patients were compared between periods. For each period analyzed, ratios of ED visits, hospital admissions, and deaths per 1,000 COVID-19 cases were calculated.
