Risk of COVID-19 to people of different ages

Coronavirus disease 2019 (COVID-19) poses a risk of infection and death to people of all ages. Data reported shows that the mortality of patients with COVID-19 increases with age. Data reported in South Korea, Spain and Italy indicates that more than 92% of deaths are concentrated in patients over 60 years of age. Less than 1% of total deaths are under age 30. It is worth noting that the proportion of deaths in the age group of over age 70 reported by China is significantly lower than the proportion reported by Korea, Spain and Italy for the same age group. See Chart 1.

The risk of infection in different age groups reported in Italy and Spain is different from the risk reported in South Korea and China. Data from Spain and Italy indicates that the risk of infection increases with age. But data from South Korea indicates that the risk is more evenly distributed across all ages. China's data indicates that patients are more concentrated in the 30-69 age group. See Chart 2. The reason for this difference could be that in addition to different age distributions, test coverage of COVID-19 and even the definition of the diagnosis could be different in different countries.

In the following analysis, the data used for South Korea and Spain are reported as of April 11, 2020 and April 9, 2020 respectively. Data for Italy is based on the 94,088 cases reported April 9, 2020. China's data is based on 44,672 cases reported as of February 11, 2020.

1. Death rate and age

The trend in reported patient mortality in the four countries is very consistent; namely, the risk of patient death increases with age. Data reported in South Korea, Spain, and Italy indicated that 90%–96% of deaths from COVID-19 patients were over the age of 60. Data previously reported in China (44,672 cases) indicated that for the same age group (over 60), the deaths made up 81% of total patient deaths.

3. Infection rate and age

The rates of COVID-19 infections in different age groups reported in Spain and Italy are not entirely consistent with those reported in South Korea and China. Data from Spain and Italy indicates that the risk of infection increases with age. However, data from South Korea indicates that the risk of developing the disease is more evenly distributed across all ages.    Data from China indicates that patients are mostly concentrated in the 30-59 age group. There are two reasons that could explain this difference. First, the four countries have different aging populations. For example, the population over 65 in South Korea is 13.2% of the population [1a]. In Spain, people over 65 comprisesis 17.9% of the population [2a], while in Italy the percent proportion of over 65 is 20% [3a]. It is worth noting that the population over 65 in China is 10.5% [4a], the lowest among the four countries. The second possible reason is that more extensive testing has been performed in South Korea [2020 coronavirus pandemic in South Korea]. As of March 24, 2020, approximately 348,582 people have been tested for the virus in South Korea and 9,037 have been positively diagnosed. The ratio of the number of tested to the number of confirmed patients was 38.5. The large number of tests might have allowed more young people with mild conditions to be detected and included in the statistics. In comparison, as of March 27, 2020, approximately 394,079 people had been tested in Italy, of whom 86,498 were confirmed positive. The ratio of the number of tested to the number of confirmed patients was 4.5. Also as of March 27, 2020, approximately 350,000 people in Spain have been tested for the virus, of whom 64,059 were diagnosed. The ratio of tested people to the confirmed patients was 5.5.

COVID-19 tests and diagnoses

Country	Tests	Confirmed Cases	Ratio	Date & Source
S Korea	348,582	9,037	38.5	Mar 24, 2020 [1]
Spain	350,000	64,059	5.5	Mar 27, 2020 [2]
Italy	394,079	86,498	4.5	Mar 27, 2020 [3]
U.S.	1,951,044	364,058	5.3	Apr 7, 2020 [5]
Japan	46,869	2,617	18.9	Apr 3, 2020 [6]

COVID-19 cases in 3 age groups

Table 1. Covid-19 death and infection rates in South Korea (9 age groups)

Data and statistics are based on the 10,450 cases reported in Korea as of April 11, 2020.

Age	Cases	% of total cases	Deaths	% of total deaths	% of death in age group
All ages	10,450	100%	208	100%
Above 80	474	4.54%	101	48.56%	21.31%
70–79	694	6.64%	62	29.81%	8.93%
60–69	1,320	12.63%	28	13.46%	2.12%
50–59	1,920	18.37%	13	6.25%	0.68%
40–49	1,396	13.36%	3	1.44%	0.21%
30–39	1,113	10.65%	1	0.48%	0.09%
20–29	2,851	27.28%	0	0.00%	-%
10–19	553	5.29%	0	0.00%	-%
0–9	129	1.23%	0	0.00%	-%
Source [1]

Table 1A. Covid-19 death and infection rates in South Korea (3 age groups)

Age	Cases	% of total cases	Deaths	% of total deaths
All ages	10,450	100%	208	100%
Above 60	2,488	23.81%	191	91.83%
30–59	4,429	42.38%	17	8.17%
0–29	3,533	33.81%	0	0.00%

Table 2. Covid-19 death and infection rates in Spain (10 age groups)

Data and statistics are based on the 109,146 cases reported in Spain as of April 9, 2020.

Age	Cases	% of total cases	Deaths	% of total deaths	% of death in age group
All ages	109,146	100.0%	7,106	100.0%
Above 90	5,346	4.9%	1,290	18.2%	24.1%
80-89	14,739	13.5%	3,035	42.7%	20.6%
70-79	17,297	15.8%	1,848	26.0%	10.7%
60-69	18,095	16.6%	624	8.8%	3.4%
50-59	20,342	18.6%	206	2.9%	1.0%
40-49	16,451	15.1%	66	0.9%	0.4%
30-39	10,518	9.6%	24	0.3%	0.2%
20-29	5,477	5.0%	11	0.2%	0.2%
10-19	593	0.5%	1	0.0%	0.2%
0-9	288	0.3%	1	0.0%	0.3%
Source [2]

Table 2A. Covid-19 death and infection rates in Spain (3 age groups)

Age	Cases	% of total cases	Deaths	% of total deaths
All ages	109,146	100.0%	7,106	100.0%
Above 60	55,477	50.83%	10,853	97.23%
30–59	47,311	43.35%	296	2.65%
0–29	6,358	5.83%	13	0.12%

Table 3. Covid-19 death and infection rates in Italy (10 age groups)

Data of infections and deaths is based on the 94,088 cases reported by Italy as of March 30, 2020.

Age	Cases	% of total cases	Deaths	% of total deaths	% of death in age group
All ages	94,312	100.0%	10,026	100.0%
Above 90	3,573	3.8%	939	9.4%	26.3%
80–89	14,186	15.0%	3,984	39.7%	28.1%
70–79	17,464	18.5%	3,456	34.5%	19.8%
60–69	16,395	17.4%	1,162	11.6%	7.1%
50–59	18,678	19.8%	369	3.7%	2.0%
40–49	12,084	12.8%	89	0.9%	0.7%
30–39	6,523	6.9%	20	0.2%	0.3%
20–29	3,830	4.1%	2	0.0%	0.1%
10–19	766	0.8%	0	0.0%	0.0%
0–9	589	0.6%	0	0.0%	0.0%
Source [3]

Table 3A. Covid-19 death and infection rates in Italy (3 age groups)

Age	Cases	% of total cases	Deaths	% of total deaths
All ages	94,312	100.0%	10,026	100.0%
Above 60	51,618	54.86%	9,541	95.21%
30–59	37,285	39.63%	478	4.77%
0–29	5,185	5.51%	2	0.02%

Table 4. Covid-19 death and infection rates in China (9 age groups)

Data of infections and deaths is based on the first 44,672 cases reported by China as of February 11, 2020.

Age	Cases	% of total cases	Deaths	% of total deaths	% of death in age group
All ages	44,672	100%	1,023	100%
Above 80	474	4.54%	101	48.56%	21.31%
70-79	3,918	8.8%	312	30.5%	8.0%
60-69	8,583	19.2%	309	30.2%	3.6%
50-59	10,008	22.4%	130	12.7%	1.3%
40-49	8,571	19.2%	38	3.7%	0.4%
30-39	7,600	17.0%	18	1.8%	0.2%
20-29	3,619	8.1%	7	0.7%	0.2%
10-19	549	1.2%	1	0.1%	0.2%
0-9	416	0.9%	0	0%	0%
Source： The epidemiological characteristics of an outbreak of 2019 novel coronavirus diseases (COVID-19) in China

Table 4A. Covid-19 death and infection rates in China (3 age groups)

Age	Cases	% of total cases	Deaths	% of total deaths
All ages	44,672	100%	1,023	100%
Above 60	13,909	31.14%	829	81.04%
30–59	26,179	58.60%	186	18.18%
0–29	4,584	10.26%	8	0.78%

表5. Covid-19 death rates in New York (10 age groups)

Data as of April 6, 2020.

Age	Deaths	% of total deaths
All Ages	5,489	100%
Above 90	616	11.2%
80–89	1,394	25.4%
70–79	1,446	26.3%
60–69	1,066	19.4%
50–59	587	10.7%
40–49	238	4.3%
30–39	107	2.0%
20–29	27	0.5%
10–19	4	0.1%
0–9	1	0%
Data source： New York Covid-19 Fatalities