Table 1. Definition of grade according to the most intensive treatment or death and the frequency of each severity grade by sex and age groups among 23,414 COVID-19 patients registered in Japan.

Age, years	N	Grade
		0. No oxygen	1. nasal cannula/ oxygen masks	2. high-flow oxygen devices/NIPPV	3. invasive mechanical ventilation	4. ECMO	5. death (regardless of treatment)
Men
20–29	1,666	97.1%	2.6%	0.1%	0.2%	0.0%	0.0%
30–39	1,595	89.0%	9.6%	1.0%	0.4%	0.1%	0.0%
40–49	2,157	78.3%	18.5%	1.9%	0.9%	0.2%	0.2%
50–59	2,593	67.6%	27.2%	2.2%	2.0%	0.3%	0.7%
60–69	2,114	55.0%	35.1%	3.6%	2.7%	0.1%	3.5%
70–79	1,997	47.1%	37.5%	3.5%	2.5%	0.2%	9.3%
80–89	1,238	38.7%	33.0%	1.9%	0.2%	0.0%	26.2%
Total	13,360	67.8%	23.9%	2.1%	1.4%	0.1%	4.5%
Women
20–29	1,546	98.3%	1.5%	0.1%	0.1%	0.0%	0.0%
30–39	1,080	96.2%	3.6%	0.1%	0.1%	0.0%	0.0%
40–49	1,180	90.8%	8.0%	0.4%	0.2%	0.1%	0.5%
50–59	1,490	82.3%	16.3%	0.7%	0.3%	0.0%	0.3%
60–69	1,401	73.2%	23.6%	1.3%	1.1%	0.0%	0.9%
70–79	1,749	63.9%	28.9%	2.1%	0.5%	0.0%	4.5%
80–89	1,608	52.2%	34.3%	1.3%	0.2%	0.0%	12.0%
Total	10,054	78.0%	17.8%	0.9%	0.4%	0.0%	2.9%

Percentage values are for row.