Surveillance Reports

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Public Health Weekly Report 2025; 18(4): 157-179

Published online December 18, 2024

https://doi.org/10.56786/PHWR.2025.18.4.1

© The Korea Disease Control and Prevention Agency

Characteristics and Trends of Coronavirus Disease 2019 Outbreak in the Republic of Korea (January 20, 2020–August 30, 2023)

Geehyuk Kim , Boyeong Ryu , Se-jin Jeong , Sun-kyung Baek *

Division of Disease Control Research Planning, Department of Data Science, Korea Disease Control and Prevention Agency, Cheongju, Korea

*Corresponding author: Sun-kyung Baek, Tel: +82-43-719-7730, E-mail: skbaek32@korea.kr

Received: November 7, 2024; Revised: December 13, 2024; Accepted: December 16, 2024

This is an Open Access aritcle distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) which permits unrestricted distribution, and reproduction in any medium, provided the original work is properly cited.

This report analyzes the characteristics of coronavirus disease 2 019 (COVID-19) cases collected through mandatory surveillance between January 20, 2020 and August 30, 2023, by age, sex, and region. During the mandatory surveillance period, 34,572,554 cases, 35,605 deaths, and 38,112 severe/critical cases were recorded. The number of COVID-19 cases gradually increased in 2020 and 2021; however, the cases surged, with 82.2% of the pandemic’s total cases reported in 2022, after the omicron variant became the dominant strain in January 2022. In March 2022, 9,959,368 cases were reported, accounting for the highest proportion (28.8%) of total cases. Individuals in their 40s (15.1%) and 30s (14.7%) represented the highest proportion of cases during the study period. Annually, the highest proportion of cases in 2020, 2021, 2022, and 2023 were observed among individuals in their 50s, 20s, 40s, and 30s, respectively. Regionally, metropolitan region accounted for 52.1% of the total cases. In non-metropolitan regions, most cases in 2020 were reported in Daegu and Gyeongbuk and increased in Busan, Ulsan, and Gyeongnam thereafter. This report complies with and conveys information on the characteristics of COVID-19 cases reported during the mandatory surveillance period. This report may serve as a reference for future respiratory infectious disease crises.

Key words COVID-19; Incidence; Mandatory surveillance; Age; Geography

Key messages

① What is known previously?

During the mandatory surveillance period, 34,572,554 coronavirus disease 2019 cases were reported. The cases gradually increased in 2020 and 2021, and surged in 2022 as the Omicron variant became the dominant strain. The severity and fatality rates peaked early but continuously declined thereafter.

② What new information is presented?

Age-specific analysis showed that individuals in their 20s and 40s accounted for 42.9% and 44.4%, respectively, whereas the proportion of individuals aged ≥60 years ranged from 19.5–28.7%.

③ What are implications?

This report provides foundational data that can be used to prepare for future infectious disease crisis.

After the first case of unexplained pneumonia was reported in Wuhan City, Hubei Province, China, in late December 2019, coronavirus disease 2019 (COVID-19) rapidly spread across countries, resulting in a pandemic that created a global public health crisis. The World Health Organization reported 776,618,091 confirmed cases as of October 13, 2024 [1]. On January 3, 2020, the Korea Disease Control and Prevention Agency (KDCA) declared a “Blue” level of infectious disease crisis alert after a report of 44 pneumonia cases of unknown origin in China. On January 20, 2020, the first confirmed case was reported among in-country arrivals, prompting an upgrade of the crisis level to “Yellow.” Mandatory surveillance of COVID-19 was implemented as Class 1 infectious disease and Class 2 infectious disease (from April 25) until August 30, 2023 [2].

As COVID-19 continued to spread, mutant viruses emerged and vaccinations were introduced, which led to the reduction of the disease severity and the transition of COVID-19 management to an endemic system. Since August 31, 2023, the surveillance system has been operated as a sentinel surveillance system [3]. In transition time, multi-layered surveillance system including monitoring of those who test positive for COVID-19 and wastewater surveillance was implemented [4]. This report aimed to summarize the trends and characteristics of confirmed COVID-19 cases throughout the pandemic and analyze them as a reference for developing strategies to address future respiratory infectious disease pandemics.

1. Subjects and Definition

According to Article 11 of the Infectious Disease Control and Prevention Act, this report utilized information on confirmed cases and deaths reported to the integrated healthcare management system as Class 1 emerging infectious diseases (COVID-19), and Class 2 infectious disease (COVID-19 after April 25, 2022) from January 20, 2020 to August 30, 2023 [5].

In accordance with the diagnostic testing criteria in the COVID-19 Response Guidelines, a confirmed case of COVID-19 was defined as an individual diagnosed through COVID-19 gene detection, virus isolation, a professional rapid antigen test (implemented on March 14, 2022), or an emergency screening test [6]. The severity of COVID-19 was classified into “severe and critical case” and “death.” A severe/critical condition was defined as requiring noninvasive ventilation/high flow oxygen, invasive ventilation, multi-organ failure, extracorporeal membrane oxygenation, or continuous renal replacement therapy while isolated following a COVID-19 diagnosis [7,8]. COVID-19 deaths were defined as cases reported as COVID-19 deaths under the Infectious Disease Control and Prevention Act, excluding deaths caused by external factors [5].

2. Methods of Analysis

Frequency analysis of COVID-19 confirmed cases was conducted based on age, sex, route of infection, and reporting region. To determine the ratio of confirmed cases to the population of each region, the incidence per 100,000 people and age-standardized incidence rate were calculated. The age-standardized incidence rate was based on the 2020 resident registration mid-year population by city, province, and age as provided by Statistics Korea. Confirmed cases in the metropolitan included Seoul, Incheon, and Gyeonggi-do. Cases in the non-metropolitan included Busan, Daegu, Gwangju, Daejeon, Ulsan, Sejong, Gangwon-do, Chungcheongbuk-do, Chungcheongnam-do, Jeollabuk-do, Jeollanam-do, Gyeongsangbuk-do, Gyeongsangnam-do, and Jeju-do. The case severity rates and case fatality rates were calculated to determine severity. The severity rate was calculated as the proportion (%) of severe/critical condition cases and deaths among confirmed cases during the specified period, while the case fatality rate was calculated as the proportion (%) of deaths among confirmed cases in the same period. The variant dominance period was defined as the week in which 50% or more of the weekly variant viruses were detected. Variant dominance period was divided into pre-dominance of the Delta variants (January 20, 2020 to July 24, 2021), dominance of Delta variants (July 25, 2021 to January 15, 2022), and dominance of Omicron variants (January 16, 2022 to August 30, 2023). All analyses were performed using Microsoft Excel 2016 (Microsoft) and Tableau 2021 (Salesforce).

1. Monthly Trend of Confirmed Cases during the Mandatory Surveillance Period

From January 2020 to August 2023, a total of 34,572,554 confirmed cases of COVID-19 were reported through mandatory surveillance, representing 67.3% of the Republic of Korea’s population (51,349,259 based on the 2020 resident registration mid-year population) (Figure 1).

Figure 1. Weekly and monthly trends in COVID-19 cases (January 20, 2020–August 30, 2023)
(A) Trends in weekly confirmed and cumulative COVID-19 cases by week (January 20, 2020–August 30, 2023). (B) Trends in monthly confirmed and cumulative COVID-19 cases by month. COVID-19=coronavirus disease 2019; Jan=January; W=week; Apr=April; Jun=June; Aug=August; Oct=October; Mar=March; Dec=December; Jul=July; Feb=February.

1) 2020: initial outbreak and spread (crisis level: “Blue”→“Yellow”→“Red”)

In 2020, there were 60,722 confirmed cases, with an incidence of 118 per 100,000 people, and 1,313 deaths, resulting in a fatality rate of 2.16% (Table 1).

Table 1. Characteristic of COVID-19 cases by year
ClassTotal
(2020.1.20.–2023.8.30.)
2020 (1.20.–)202120222023 (–8.30.)
Total34,572,55460,722569,94328,424,3495,517,540
Age (yr)
0–93,270,282 (9.5)2,091 (3.4)47,042 (8.3)2,967,570 (10.4)253,579 (4.6)
10–194,246,977 (12.3)3,769 (6.2)59,269 (10.4)3,603,042 (12.7)580,897 (10.5)
20–295,001,143 (14.5)9,708 (16.0)84,714 (14.9)4,141,840 (14.6)764,881 (13.9)
30–395,077,726 (14.7)7,726 (12.7)83,946 (14.7)4,149,721 (14.6)836,333 (15.2)
40–495,237,546 (15.1)8,621 (14.2)83,495 (14.6)4,337,066 (15.3)808,364 (14.7)
50–594,531,012 (13.1)11,393 (18.8)80,146 (14.1)3,680,898 (12.9)758,575 (13.7)
60–693,898,836 (11.3)9,624 (15.8)80,209 (14.1)3,050,649 (10.7)758,354 (13.7)
70–792,056,083 (5.9)4,768 (7.9)33,643 (5.9)1,553,122 (5.5)464,550 (8.4)
≥801,252,949 (3.6)3,022 (5.0)17,479 (3.1)940,441 (3.3)292,007 (5.3)
Sex
Male15,892,229 (46.0)29,597 (48.7)298,520 (52.4)13,156,843 (46.3)2,407,269 (43.6)
Female18,680,325 (54.0)31,125 (51.3)271,423 (47.6)15,267,506 (53.7)3,110,271 (56.4)
Transmission route
Local cases34,492,629 (99.8)55,343 (91.1)557,985 (97.9)28,368,494 (99.8)5,510,807 (99.9)
Imported cases79,925 (0.2)5,379 (8.9)11,958 (2.1)55,855 (0.2)6,733 (0.1)
Region
Metropolitan
Seoul6,751,335 (19.5)18,992 (31.3)206,109 (36.2)5,436,495 (19.1)1,089,739 (19.8)
Incheon1,991,892 (5.8)2,839 (4.7)33,880 (5.9)1,649,641 (5.8)305,532 (5.5)
Gyeonggi9,266,797 (26.8)14,450 (23.8)171,882 (30.2)7,680,724 (27.0)1,399,741 (25.4)
Non-metropolitan
Busan2,092,642 (6.1)1,867 (3.1)23,207 (4.1)1,691,534 (6.0)376,034 (6.8)
Daegu1,516,421 (4.4)7,801 (12.8)15,323 (2.7)1,245,690 (4.4)247,607 (4.5)
Gwangju1,018,499 (2.9)1,081 (1.8)6,945 (1.2)841,026 (3.0)169,447 (3.1)
Daejeon1,013,275 (2.9)845 (1.4)11,405 (2.0)836,323 (2.9)164,702 (3.0)
Ulsan738,128 (2.1)672 (1.1)6,200 (1.1)611,309 (2.2)119,947 (2.2)
Sejong273,413 (0.8)149 (0.2)1,993 (0.3)228,054 (0.8)43,217 (0.8)
Gangwon1,005,836 (2.9)1,207 (2.0)11,198 (2.0)847,429 (3.0)146,002 (2.6)
Chungbuk1,075,474 (3.1)1,163 (1.9)10,335 (1.8)900,824 (3.2)163,152 (3.0)
Chungnam1,390,798 (4.0)1,653 (2.7)16,441 (2.9)1,155,658 (4.1)217,046 (3.9)
Jeonbuk1,167,948 (3.4)837 (1.4)8,731 (1.5)963,247 (3.4)195,133 (3.5)
Jeonnam1,142,483 (3.3)560 (0.9)5,518 (1.0)941,437 (3.3)194,968 (3.5)
Gyeongbuk1,581,207 (4.6)2,424 (4.0)12,890 (2.3)1,311,391 (4.6)254,502 (4.6)
Gyeongnam2,075,991 (6.0)1,325 (2.2)19,351 (3.4)1,712,297 (6.0)343,018 (6.2)
Jeju451,523 (1.3)416 (0.7)4,222 (0.7)361,316 (1.3)85,569 (1.6)
Quarantine18,892 (0.1)2,441 (4.0)4,313 (0.8)9,954 (0.04)2,184 (0.04)
Severity
Deaths35,6051,3135,16425,9153,213
Severe/critical cases38,1122,00610,38220,0235,701
Case severity rate (%)a)0.194.332.250.140.15
Case fatality rate (%)a)0.102.160.910.090.06

Unit: n (%). COVID-19=coronavirus disease 2019. a)The case severity rate and case fatality rate were analyzed continuously observing the progress of confirmed cases during each respective period. The monitoring period includes confirmed cases up to two weeks prior (August 12th, 2023, 12 am).



(1) January–February: initial outbreak (“Blue”→“Yellow”→“Red”)

The first confirmed case was reported on January 20, 2020, among travelers entering the country from Wuhan City. Subsequently, there were 29 individual sporadic cases, followed by the first large-scale outbreak centered in Daegu and Gyeongsangbuk-do. The number of daily confirmed cases gradually increased, reaching 190 cases on February 22, and spiked to 2,920 cases by the end of February, compared to 11 in January.

(2) March–December: outbreak spread and pandemic response (crisis level: “Red”)

From March 2020 to December 2020, the number of confirmed cases fluctuated, with a general upward trend. Significant outbreaks occurred in August (5,651 cases) and December (26,523 cases), compared to the lower numbers at the start of the year (10 in January and 2,920 in February). In August, outbreaks primarily occurred in religious facilities in metropolitan areas, large urban gatherings, and multi-use facilities. By November, the outbreaks has spread nationwide, focusing on gatherings and religious facilities.

2) 2021: vaccine introduction and resurgence (crisis level: “Red”)

In 2021, there were 569,943 confirmed cases, with an incidence rate of 1,110 per 100,000 people, and 5,164 deaths, yielding a case fatality rate of 0.91%. In the first half of the year, there were about 10,000 monthly confirmed cases (17,470 in January and 11,466 in February), which increased to more than 100,000 in the second half of the year (82,499 in November and 183,514 in December). On February 26, 2021, vaccinations began, and the primary national vaccination rate reached 70% (September 17, 2020). Despite vaccination efforts, the spread of the Delta variant (July 2021–January 2022) led to a large-scale epidemic, especially in the metropolitan region.

3) 2022–2023: Omicron variants and surge in increase confirmed cases (crisis level: “Red”→“Orange”)

In 2022 and 2023, there were 28,424,349 and 5,517,540 confirmed cases, with an incidence rates of 55,355 and 10,745 per 100,000 people, respectively. There were 25,915 and 3,213 deaths, with case fatality rates of 0.09% and 0.06%, respectively (Table 1).

The emergence of the Omicron variant in December 2021 led to an exponential increase in confirmed cases, exceeding 50% of detected cases from January 2022 onward. When comparing monthly outbreaks, the highest number of confirmed cases during the COVID-19 pandemic occurred in March 2022, with 9,959,368 confirmed cases (28.8% of the total outbreak). In April, the number of confirmed cases decreased to approximately 4,142,095, which is still a higher number of cases than before 2022. Following the March 2022 peak, the number of cases declined, with one peak in summer and winter, with 3,469,887 cases in August and 1,960,578 cases in December. In 2023, monthly cases stabilized at approximately 300,000 since February. On August 31, 2023, mandatory surveillance ended with the transition of COVID-19 to Class 4 infectious disease sentinel surveillance.

2. Basic Characteristics and Geographic Distribution of Confirmed Cases by Year

1) Demographic characteristics and routes of infection

During the entire period, individuals in their 40s accounted for the largest proportion of COVID-19 confirmed cases (5,237,546; 15.1%) and those aged 80 and older accounted for the smallest proportion (1,252,949; 3.6%). By year, the largest proportion of cases by age group was among those in their 50s in 2020 at 18.8% (11,393), followed by those in their 20s in 2021 at 14.9% (84,714), those in their 40s in 2022 at 15.3% (4,337,066), and those in their 30s in 2023 at 15.2% (836,333). By sex, female confirmed cases (18,680,325; 54.0%) outnumbered male confirmed cases (15,892,229; 46.0%), across all years except 2021. Most cases were domestic (34,492,629; 99.8%), with imported cases accounting for only 0.2% (79,925).

2) Incidence by region

By region, the highest number of cases occurred in Gyeonggi-do (9,266,797; 26.8%), followed by Seoul (6,751,335; 19.5%), and Busan (2,092,642; 6.1%) in order. By year, the largest proportion of cases (46.1% to 66.3%) occurred in Seoul and Gyeonggi-do (Tables 1, 2).

In terms of confirmed cases by region, the incidence per 100,000 people was highest in Sejong (78,778), followed by Seoul (70,818), and Gwangju (70,510), with variations by year (Table 2). In 2020, the highest numbers of cases were in Daegu (324), followed by Seoul (199) and Gyeonggi-do (109); in 2021, the highest number of cases were in Seoul (2,162), followed by Gyeonggi-do (1,300) and Incheon (1,159) in this order. In 2022, the highest numbers of cases were reported in Sejong (65,708), Gwangju (58,224), and Gyeonggi-do (58,098) in this order. In 2023, the regions with the highest incidence were Jeju-do (12,824), Sejong (12,452), and Gwangju (11,731) in this order.

Table 2. COVID-19 cases and incidence rates by region
Total2020 (1.20.–)202120222023 (–8.30.)
Case
(crude incidence rate)
Standardized ratea)Case (crude incidence rate)Standardized ratea)Case
(crude incidence rate)
Standardized ratea)Case
(crude incidence rate)
Standardized ratea)Case
(crude incidence rate)
Standardized ratea)
Total34,572,554 (67,328)67,32860,722 (118)118569,943 (1,110)1,11028,424,349 (55,355)55,3555,517,540 (10,745)10,745
Seoul6,751,335 (70,818)70,47018,992 (199)199206,109 (2,162)2,1635,436,495 (57,026)56,8151,089,739 (11,431)11,293
Busan2,092,642 (62,159)62,8341,867 (55)5423,207 (689)6901,691,534 (50,245)51,032376,034 (11,170)11,058
Daegu1,516,421 (62,917)63,1437,801 (324)32215,323 (636)6381,245,690 (51,684)51,898247,607 (10,273)10,285
Incheon1,991,892 (68,166)68,1002,839 (97)9833,880 (1,159)1,1621,649,641 (56,454)56,286305,532 (10,456)10,554
Gwangju1,018,499 (70,510)70,0261,081 (75)776,945 (481)479841,026 (58,224)57,608169,447 (11,731)11,862
Daejeon1,013,275 (69,442)69,063845 (58)5811,405 (782)778836,323 (57,315)56,864164,702 (11,287)11,363
Ulsan738,128 (64,970)64,864672 (59)676,200 (546)540611,309 (53,807)53,489119,947 (10,558)10,768
Sejong273,413 (78,778)75,792149 (43)431,993 (574)558228,054 (65,708)62,34443,217 (12,452)12,848
Gyeonggi9,266,797 (70,096)69,59614,450 (109)112171,882 (1,300)1,3007,680,724 (58,098)57,4631,399,741 (10,588)10,721
Gangwon1,005,836 (65,797)67,3761,207 (79)7911,198 (733)747847,429 (55,435)56,950146,002 (9,551)9,601
Chungbuk1,075,474 (67,624)68,0111,163 (73)7210,335 (650)659900,824 (56,642)57,020163,152 (10,259)10,259
Chungnam1,390,798 (65,974)66,3031,653 (78)8016,441 (780)7891,155,658 (54,820)55,119217,046 (10,296)10,316
Jeonbuk1,167,948 (64,890)65,227837 (47)468,731 (485)496963,247 (53,517)54,010195,133 (10,841)10,675
Jeonnam1,142,483 (61,829)62,652560 (30)325,518 (299)308941,437 (50,949)51,957194,968 (10,551)10,356
Gyeongbuk1,581,207 (59,990)61,0062,424 (92)9212,890 (489)5031,311,391 (49,754)50,793254,502 (9,656)9,618
Gyeongnam2,075,991 (62,304)62,3701,325 (40)4019,351 (581)5831,712,297 (51,389)51,467343,018 (10,295)10,280
Jeju451,523 (67,667)67,117416 (62)634,222 (633)631361,316 (54,149)53,55685,569 (12,824)12,867

Unit: n (incidence per 100,000 population). COVID-19=coronavirus disease 2019. a)Age-adjusted rates (standard population: mid-year estimates of the population for 2020).



The age-standardized incidence, calculated by standardizing the proportion of the region’s population by age, was the highest in Sejong (75,792), followed by Seoul (70,470), and Gwangju (70,026) across all years (Table 2). In 2020, the highest age-standardized incidence was in Daegu (322), followed by Seoul (199), and Gyeonggi-do (112) in order. In 2021, the highest age-standardized incidence was in Seoul (2,163), followed by Gyeonggi-do (1,300), and Incheon (1,162). In 2022, Sejong (62,344) showed the highest age-standardized incidence, followed by Gwangju (57,608), and Gyeonggi-do (57,463) in order. In 2023, Jeju-do (12,867), Sejong (12,848), and Gwangju (11,862) had the highest age-standardized incidence in that order.

3. Basic Characteristics and Geographic Incidence of Confirmed Cases by Variant Dominance Period

The number of COVID-19 confirmed cases differed across variant dominance periods, with 187,339 cases during the Delta variant pre-dominance period, 500,410 cases during the Delta variant dominance period, and 33,884,805 cases during the Omicron variant dominance period (Table 3). The average daily number of confirmed cases was 340 during the Delta variant pre-dominance period, 2,876 during the Delta variant dominance period, and 57,335 during the Omicron variant dominance period.

Table 3. Characteristic of COVID-19 cases by variant dominant period
ClassTotal
(2020.1.20.–2023.8.30.)
Pre-Delta dominant period
(2020.1.20.–2021.7.24.)
Delta dominant period
(2021.7.25.–2022.1.15.)
Omicron dominant period(2022.1.16.–2023.8.30.)
Total (average daily case)34,572,554 (26,231)187,339 (340)500,410 (2,876)33,884,805 (57,335)
Age (yr)
0–93,270,282 (9.5)8,914 (4.8)47,378 (9.5)3,213,990 (9.5)
10–194,246,977 (12.3)14,407 (7.7)55,961 (11.2)4,176,609 (12.3)
20–295,001,143 (14.5)31,608 (16.9)72,070 (14.4)4,897,465 (14.5)
30–395,077,726 (14.7)27,270 (14.6)73,565 (14.7)4,976,891 (14.7)
40–495,237,546 (15.1)29,639 (15.8)71,544 (14.3)5,136,363 (15.2)
50–594,531,012 (13.1)33,776 (18.0)64,582 (12.9)4,432,654 (13.1)
60–693,898,836 (11.3)24,842 (13.3)70,267 (14.0)3,803,727 (11.2)
70–792,056,083 (5.9)10,800 (5.8)29,444 (5.9)2,015,839 (5.9)
≥801,252,949 (3.6)6,083 (3.2)15,599 (3.1)1,231,267 (3.6)
Sex
Male15,892,229 (46.0)95,427 (50.9)262,151 (52.4)15,534,651 (45.8)
Female18,680,325 (54.0)91,912 (49.1)238,259 (47.6)18,350,154 (54.2)
Transmission route
Local cases34,492,629 (99.8)172,532 (92.1)450,343 (90.0)33,196,273 (98.0)
Imported cases79,925 (0.2)14,807 (7.9)50,067 (10.0)688,532 (2.0)
Region
Metropolitan
Seoul6,751,335 (19.5)61,112 (32.6)179,580 (35.9)6,510,643 (19.2)
Incheon1,991,892 (5.8)8,423 (4.5)31,545 (6.3)1,951,924 (5.8)
Gyeonggi9,266,797 (26.8)52,791 (28.2)153,602 (30.7)9,060,404 (26.7)
Non-metropolitan
Busan2,092,642 (6.1)7,609 (4.1)20,114 (4.0)2,064,919 (6.1)
Daegu1,516,421 (4.4)11,252 (6.0)13,399 (2.7)1,491,770 (4.4)
Gwangju1,018,499 (2.9)3,232 (1.7)6,634 (1.3)1,008,633 (3.0)
Daejeon1,013,275 (2.9)3,678 (2.0)9,340 (1.9)1,000,257 (3.0)
Ulsan738,128 (2.1)3,121 (1.7)4,264 (0.9)730,743 (2.2)
Sejong273,413 (0.8)684 (0.4)1,654 (0.3)271,075 (0.8)
Gangwon1,005,836 (2.9)4,198 (2.2)9,393 (1.9)992,245 (2.9)
Chungbuk1,075,474 (3.1)3,639 (1.9)8,776 (1.8)1,063,059 (3.1)
Chungnam1,390,798 (4.0)4,618 (2.5)15,160 (3.0)1,371,020 (4.0)
Jeonbuk1,167,948 (3.4)2,613 (1.4)8,233 (1.6)1,157,102 (3.4)
Jeonnam1,142,483 (3.3)1,904 (1.0)5,557 (1.1)1,135,022 (3.3)
Gyeongbuk1,581,207 (4.6)5,269 (2.8)11,351 (2.3)1,564,587 (4.6)
Gyeongnam2,075,991 (6.0)6,532 (3.5)15,860 (3.2)2,053,599 (6.1)
Jeju451,523 (1.3)1,598 (0.9)3,279 (0.7)446,646 (1.3)
Quarantine18,892 (0.1)5,066 (2.7)2,669 (0.5)11,157 (0.03)
Severity
Deaths35,6052,1394,73328,733
Severe/critical cases38,1124,6658,29625,151
Case severity rate (%)a)0.192.972.140.15
Case fatality rate (%)a)0.101.140.950.08

Unit: n (%). COVID-19=coronavirus disease 2019. a)The case severity rate and case fatality rate were analyzed continuously observing the progress of confirmed cases during each respective period. The monitoring period includes confirmed cases up to two weeks prior (August 12th, 2023, 12 am).



The highest incidence for each dominance period by age group was 18.0% (33,776) in their 50s during the Delta variant pre-dominance period, 14.7% (73,565) in their 30s during the Delta variant dominance period, and 15.2% (5,136,363) in their 40s during the Omicron variant dominance period. By sex, female accounted for a larger proportion of confirmed cases during all periods except the Omicron variant dominance period. As for the route of infection, imported cases accounted for 10% of cases during the Delta variant dominance period and decreased to 2% during the Omicron variant dominance period.

During the variant dominance periods, most cases (51.7% to 72.9%) occurred in the metropolitan region.

4. Severity

During the entire pandemic, the case severity rate and case fatality rate were 0.19% and 0.10%, respectively (Tables 1, 3, Figure 2). In 2020, the case severity rate was 4.33% and the case fatality rate was 2.16%, showing fluctuating trends. In 2021, the severity rate was 2.25% and the fatality rate was 0.91%, indicating an overall decrease, followed by an increase in severity in the second half of the year, when the Delta variants became dominant. By month in 2021, the case severity rate decreased steadily from 3.16% in January, began to rise in September, peaked at 3.02% in November, and then declined again. The fatality rate had the lowest rate of 0.31% in July and increased in September, peaking at 1.55% in November. From 2022 to the end of mandatory surveillance in 2023, the severity rate and fatality rate decreased substantially as the Omicron variants became dominant. By 2022, the severity and fatality rates were 0.14% and 0.09%, respectively, while in 2023, they were 0.15% and 0.06%, respectively.

Figure 2. Monthly COVID-19 case severity rate and case fatality rate
COVID-19=coronavirus disease 2019.

During the entire COVID-19 pandemic, both severity and fatality rates were highest in 2020 (4.33% and 2.16%, respectively). After 2022, the severity rate remained consistently low at 0.14%, and the fatality rate reached its lowest point of 0.06% in 2023. By variant dominance period, death and severe/critical condition cases were highest during the Omicron variant dominance period (28,733 and 25,151, respectively), while the severity and fatality rates were highest during the Delta variant pre-dominance period (2.97% and 1.14%, respectively).

The present report analyzed COVID-19 data reported to the KDCA from January 20, 2020 to August 30, 2023, covering the mandatory surveillance period of COVID-19 infection, thereby investigating the outbreak trends and characteristics.

In 2020 and 2021, confirmed cases of COVID-19 gradually increased. After January 2022 corresponding to the Omicron variant dominance period, there was an rapidly rise in cases in 2022, accounting for 82.2% of all confirmed cases during the entire surveillance period. In particular, March 2022 recorded the highest monthly number of confirmed cases at 9,959,368. The average daily case was highest during the Omicron variant dominance period, which included 57,335 cases. By age group, the proportion of confirmed cases during the mandatory surveillance period was highest in those in their 40s (15.1%), 30s (14.7%), and 20s (14.5%), who are more socially active. Variations in age proportions by year were 1.1% (14.2–15.3%) in their 40s, 2.1% (13.9–16.0%) in their 20s, 2.2% (3.1–5.3%) in their 80s and older, and 2.5% (12.7–15.2%) in their 30s, compared to 7.0% (3.4–10.4%) in those aged 9 and under, 6.5% (6.2–12.7%) in their 10s, 5.9% (12.9–18.8%) in their 50s, and 5.1% (10.7–15.8%) in their 60s, indicating that the occurence of COVID-19 was different between younger and older age groups at different times. In addition, the proportion of confirmed cases in the metropolitan region compared to the whole country was 59.7% in 2020, 72.3% in 2021, 52.0% in 2022, and 50.7% in 2023. These were higher than the proportion of the population in the metropolitan region (50%), suggesting a disproportionately higher number of confirmed cases in this region.

Severity was highest in the early stages of the pandemic, fluctuated over time, and began decreasing consistently from 2021 onwards. This could be attributed to the stabilization of the COVID-19 response system and the start of COVID-19 vaccination as the COVID-19 pandemic continued [9]. However, the second half of 2021 saw an increase in severity and fatality rates with the emergence of the Delta variant. In 2022, the severity rate declined significantly with the emergence of the Omicron variants, which demonstrated higher transmissibility but lower severity compared to previous variants [10]. In addition, COVID-19 was regarded as a manageable disease due to continued vaccination, treatment, and other measures, leading to changes in the monitoring system in 2023.

When comparing COVID-19 outbreaks by year and variant dominance, temporal categorization revealed some differences. However, adopting a multifaceted approach in future analyses could provide more comprehensive insights by considering diverse influencing factors beyond time periods.

Using the information collected during the mandatory surveillance of COVID-19, the KDCA produced statistics and publicized them through press releases to monitor the daily outbreak situation. Moreover, this information served as a basis for research on risk assessment for outbreaks, forecasting to establish response strategies, and risk factor analysis. Since confirmed case reports were influenced by quarantine policies, healthcare systems, COVID-19 variants, and non-pharmaceutical interventions such as vaccination, it is important to interpret trends with caution while considering these factors. Therefore, further analysis is recommended to account for the impact of various interventions, as this could provide a foundation for preparing for future infectious disease crises.

Ethics Statement: Not applicable.

Funding Source: None.

Acknowledgments: We would like to thank regional centers for Disease Control and Prevention, local governments and healthcare facilities for investigation of COVID-19 deaths.

Conflict of Interest: Sun-kyung Baek is an editorial board member of the journal, but was not involved in the review process of this manuscript. Otherwise, there is no conflict of interest to declare.

Author Contributions: Conceptualization: GHK, BYR, SKB. Data curation: GHK, SJJ. Formal analysis: GHK, BYR. Investigation: GHK, BYR, SJJ. Methodology: GHK, BYR. Project administration: BYR, SKB. Resources: GHK, SJJ. Software: GHK, BYR, SJJ. Supervision: SKB. Validation: BYR, SKB. Visualization: GHK, BYR. Writing – original draft: GHK. Writing – review & editing: BYR, SKB..

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Surveillance Reports

Public Health Weekly Report 2025; 18(4): 157-179

Published online January 23, 2025 https://doi.org/10.56786/PHWR.2025.18.4.1

Copyright © The Korea Disease Control and Prevention Agency.

Characteristics and Trends of Coronavirus Disease 2019 Outbreak in the Republic of Korea (January 20, 2020–August 30, 2023)

Geehyuk Kim , Boyeong Ryu , Se-jin Jeong , Sun-kyung Baek *

Division of Disease Control Research Planning, Department of Data Science, Korea Disease Control and Prevention Agency, Cheongju, Korea

Correspondence to:*Corresponding author: Sun-kyung Baek, Tel: +82-43-719-7730, E-mail: skbaek32@korea.kr

Received: November 7, 2024; Revised: December 13, 2024; Accepted: December 16, 2024

This is an Open Access aritcle distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) which permits unrestricted distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This report analyzes the characteristics of coronavirus disease 2 019 (COVID-19) cases collected through mandatory surveillance between January 20, 2020 and August 30, 2023, by age, sex, and region. During the mandatory surveillance period, 34,572,554 cases, 35,605 deaths, and 38,112 severe/critical cases were recorded. The number of COVID-19 cases gradually increased in 2020 and 2021; however, the cases surged, with 82.2% of the pandemic’s total cases reported in 2022, after the omicron variant became the dominant strain in January 2022. In March 2022, 9,959,368 cases were reported, accounting for the highest proportion (28.8%) of total cases. Individuals in their 40s (15.1%) and 30s (14.7%) represented the highest proportion of cases during the study period. Annually, the highest proportion of cases in 2020, 2021, 2022, and 2023 were observed among individuals in their 50s, 20s, 40s, and 30s, respectively. Regionally, metropolitan region accounted for 52.1% of the total cases. In non-metropolitan regions, most cases in 2020 were reported in Daegu and Gyeongbuk and increased in Busan, Ulsan, and Gyeongnam thereafter. This report complies with and conveys information on the characteristics of COVID-19 cases reported during the mandatory surveillance period. This report may serve as a reference for future respiratory infectious disease crises.

Keywords: COVID-19, Incidence, Mandatory surveillance, Age, Geography

Body

Key messages

① What is known previously?

During the mandatory surveillance period, 34,572,554 coronavirus disease 2019 cases were reported. The cases gradually increased in 2020 and 2021, and surged in 2022 as the Omicron variant became the dominant strain. The severity and fatality rates peaked early but continuously declined thereafter.

② What new information is presented?

Age-specific analysis showed that individuals in their 20s and 40s accounted for 42.9% and 44.4%, respectively, whereas the proportion of individuals aged ≥60 years ranged from 19.5–28.7%.

③ What are implications?

This report provides foundational data that can be used to prepare for future infectious disease crisis.

Introduction

After the first case of unexplained pneumonia was reported in Wuhan City, Hubei Province, China, in late December 2019, coronavirus disease 2019 (COVID-19) rapidly spread across countries, resulting in a pandemic that created a global public health crisis. The World Health Organization reported 776,618,091 confirmed cases as of October 13, 2024 [1]. On January 3, 2020, the Korea Disease Control and Prevention Agency (KDCA) declared a “Blue” level of infectious disease crisis alert after a report of 44 pneumonia cases of unknown origin in China. On January 20, 2020, the first confirmed case was reported among in-country arrivals, prompting an upgrade of the crisis level to “Yellow.” Mandatory surveillance of COVID-19 was implemented as Class 1 infectious disease and Class 2 infectious disease (from April 25) until August 30, 2023 [2].

As COVID-19 continued to spread, mutant viruses emerged and vaccinations were introduced, which led to the reduction of the disease severity and the transition of COVID-19 management to an endemic system. Since August 31, 2023, the surveillance system has been operated as a sentinel surveillance system [3]. In transition time, multi-layered surveillance system including monitoring of those who test positive for COVID-19 and wastewater surveillance was implemented [4]. This report aimed to summarize the trends and characteristics of confirmed COVID-19 cases throughout the pandemic and analyze them as a reference for developing strategies to address future respiratory infectious disease pandemics.

Methods

1. Subjects and Definition

According to Article 11 of the Infectious Disease Control and Prevention Act, this report utilized information on confirmed cases and deaths reported to the integrated healthcare management system as Class 1 emerging infectious diseases (COVID-19), and Class 2 infectious disease (COVID-19 after April 25, 2022) from January 20, 2020 to August 30, 2023 [5].

In accordance with the diagnostic testing criteria in the COVID-19 Response Guidelines, a confirmed case of COVID-19 was defined as an individual diagnosed through COVID-19 gene detection, virus isolation, a professional rapid antigen test (implemented on March 14, 2022), or an emergency screening test [6]. The severity of COVID-19 was classified into “severe and critical case” and “death.” A severe/critical condition was defined as requiring noninvasive ventilation/high flow oxygen, invasive ventilation, multi-organ failure, extracorporeal membrane oxygenation, or continuous renal replacement therapy while isolated following a COVID-19 diagnosis [7,8]. COVID-19 deaths were defined as cases reported as COVID-19 deaths under the Infectious Disease Control and Prevention Act, excluding deaths caused by external factors [5].

2. Methods of Analysis

Frequency analysis of COVID-19 confirmed cases was conducted based on age, sex, route of infection, and reporting region. To determine the ratio of confirmed cases to the population of each region, the incidence per 100,000 people and age-standardized incidence rate were calculated. The age-standardized incidence rate was based on the 2020 resident registration mid-year population by city, province, and age as provided by Statistics Korea. Confirmed cases in the metropolitan included Seoul, Incheon, and Gyeonggi-do. Cases in the non-metropolitan included Busan, Daegu, Gwangju, Daejeon, Ulsan, Sejong, Gangwon-do, Chungcheongbuk-do, Chungcheongnam-do, Jeollabuk-do, Jeollanam-do, Gyeongsangbuk-do, Gyeongsangnam-do, and Jeju-do. The case severity rates and case fatality rates were calculated to determine severity. The severity rate was calculated as the proportion (%) of severe/critical condition cases and deaths among confirmed cases during the specified period, while the case fatality rate was calculated as the proportion (%) of deaths among confirmed cases in the same period. The variant dominance period was defined as the week in which 50% or more of the weekly variant viruses were detected. Variant dominance period was divided into pre-dominance of the Delta variants (January 20, 2020 to July 24, 2021), dominance of Delta variants (July 25, 2021 to January 15, 2022), and dominance of Omicron variants (January 16, 2022 to August 30, 2023). All analyses were performed using Microsoft Excel 2016 (Microsoft) and Tableau 2021 (Salesforce).

Results

1. Monthly Trend of Confirmed Cases during the Mandatory Surveillance Period

From January 2020 to August 2023, a total of 34,572,554 confirmed cases of COVID-19 were reported through mandatory surveillance, representing 67.3% of the Republic of Korea’s population (51,349,259 based on the 2020 resident registration mid-year population) (Figure 1).

Figure 1. Weekly and monthly trends in COVID-19 cases (January 20, 2020–August 30, 2023)
(A) Trends in weekly confirmed and cumulative COVID-19 cases by week (January 20, 2020–August 30, 2023). (B) Trends in monthly confirmed and cumulative COVID-19 cases by month. COVID-19=coronavirus disease 2019; Jan=January; W=week; Apr=April; Jun=June; Aug=August; Oct=October; Mar=March; Dec=December; Jul=July; Feb=February.

1) 2020: initial outbreak and spread (crisis level: “Blue”→“Yellow”→“Red”)

In 2020, there were 60,722 confirmed cases, with an incidence of 118 per 100,000 people, and 1,313 deaths, resulting in a fatality rate of 2.16% (Table 1).

Characteristic of COVID-19 cases by year
ClassTotal
(2020.1.20.–2023.8.30.)
2020 (1.20.–)202120222023 (–8.30.)
Total34,572,55460,722569,94328,424,3495,517,540
Age (yr)
0–93,270,282 (9.5)2,091 (3.4)47,042 (8.3)2,967,570 (10.4)253,579 (4.6)
10–194,246,977 (12.3)3,769 (6.2)59,269 (10.4)3,603,042 (12.7)580,897 (10.5)
20–295,001,143 (14.5)9,708 (16.0)84,714 (14.9)4,141,840 (14.6)764,881 (13.9)
30–395,077,726 (14.7)7,726 (12.7)83,946 (14.7)4,149,721 (14.6)836,333 (15.2)
40–495,237,546 (15.1)8,621 (14.2)83,495 (14.6)4,337,066 (15.3)808,364 (14.7)
50–594,531,012 (13.1)11,393 (18.8)80,146 (14.1)3,680,898 (12.9)758,575 (13.7)
60–693,898,836 (11.3)9,624 (15.8)80,209 (14.1)3,050,649 (10.7)758,354 (13.7)
70–792,056,083 (5.9)4,768 (7.9)33,643 (5.9)1,553,122 (5.5)464,550 (8.4)
≥801,252,949 (3.6)3,022 (5.0)17,479 (3.1)940,441 (3.3)292,007 (5.3)
Sex
Male15,892,229 (46.0)29,597 (48.7)298,520 (52.4)13,156,843 (46.3)2,407,269 (43.6)
Female18,680,325 (54.0)31,125 (51.3)271,423 (47.6)15,267,506 (53.7)3,110,271 (56.4)
Transmission route
Local cases34,492,629 (99.8)55,343 (91.1)557,985 (97.9)28,368,494 (99.8)5,510,807 (99.9)
Imported cases79,925 (0.2)5,379 (8.9)11,958 (2.1)55,855 (0.2)6,733 (0.1)
Region
Metropolitan
Seoul6,751,335 (19.5)18,992 (31.3)206,109 (36.2)5,436,495 (19.1)1,089,739 (19.8)
Incheon1,991,892 (5.8)2,839 (4.7)33,880 (5.9)1,649,641 (5.8)305,532 (5.5)
Gyeonggi9,266,797 (26.8)14,450 (23.8)171,882 (30.2)7,680,724 (27.0)1,399,741 (25.4)
Non-metropolitan
Busan2,092,642 (6.1)1,867 (3.1)23,207 (4.1)1,691,534 (6.0)376,034 (6.8)
Daegu1,516,421 (4.4)7,801 (12.8)15,323 (2.7)1,245,690 (4.4)247,607 (4.5)
Gwangju1,018,499 (2.9)1,081 (1.8)6,945 (1.2)841,026 (3.0)169,447 (3.1)
Daejeon1,013,275 (2.9)845 (1.4)11,405 (2.0)836,323 (2.9)164,702 (3.0)
Ulsan738,128 (2.1)672 (1.1)6,200 (1.1)611,309 (2.2)119,947 (2.2)
Sejong273,413 (0.8)149 (0.2)1,993 (0.3)228,054 (0.8)43,217 (0.8)
Gangwon1,005,836 (2.9)1,207 (2.0)11,198 (2.0)847,429 (3.0)146,002 (2.6)
Chungbuk1,075,474 (3.1)1,163 (1.9)10,335 (1.8)900,824 (3.2)163,152 (3.0)
Chungnam1,390,798 (4.0)1,653 (2.7)16,441 (2.9)1,155,658 (4.1)217,046 (3.9)
Jeonbuk1,167,948 (3.4)837 (1.4)8,731 (1.5)963,247 (3.4)195,133 (3.5)
Jeonnam1,142,483 (3.3)560 (0.9)5,518 (1.0)941,437 (3.3)194,968 (3.5)
Gyeongbuk1,581,207 (4.6)2,424 (4.0)12,890 (2.3)1,311,391 (4.6)254,502 (4.6)
Gyeongnam2,075,991 (6.0)1,325 (2.2)19,351 (3.4)1,712,297 (6.0)343,018 (6.2)
Jeju451,523 (1.3)416 (0.7)4,222 (0.7)361,316 (1.3)85,569 (1.6)
Quarantine18,892 (0.1)2,441 (4.0)4,313 (0.8)9,954 (0.04)2,184 (0.04)
Severity
Deaths35,6051,3135,16425,9153,213
Severe/critical cases38,1122,00610,38220,0235,701
Case severity rate (%)a)0.194.332.250.140.15
Case fatality rate (%)a)0.102.160.910.090.06

Unit: n (%). COVID-19=coronavirus disease 2019. a)The case severity rate and case fatality rate were analyzed continuously observing the progress of confirmed cases during each respective period. The monitoring period includes confirmed cases up to two weeks prior (August 12th, 2023, 12 am)..



(1) January–February: initial outbreak (“Blue”→“Yellow”→“Red”)

The first confirmed case was reported on January 20, 2020, among travelers entering the country from Wuhan City. Subsequently, there were 29 individual sporadic cases, followed by the first large-scale outbreak centered in Daegu and Gyeongsangbuk-do. The number of daily confirmed cases gradually increased, reaching 190 cases on February 22, and spiked to 2,920 cases by the end of February, compared to 11 in January.

(2) March–December: outbreak spread and pandemic response (crisis level: “Red”)

From March 2020 to December 2020, the number of confirmed cases fluctuated, with a general upward trend. Significant outbreaks occurred in August (5,651 cases) and December (26,523 cases), compared to the lower numbers at the start of the year (10 in January and 2,920 in February). In August, outbreaks primarily occurred in religious facilities in metropolitan areas, large urban gatherings, and multi-use facilities. By November, the outbreaks has spread nationwide, focusing on gatherings and religious facilities.

2) 2021: vaccine introduction and resurgence (crisis level: “Red”)

In 2021, there were 569,943 confirmed cases, with an incidence rate of 1,110 per 100,000 people, and 5,164 deaths, yielding a case fatality rate of 0.91%. In the first half of the year, there were about 10,000 monthly confirmed cases (17,470 in January and 11,466 in February), which increased to more than 100,000 in the second half of the year (82,499 in November and 183,514 in December). On February 26, 2021, vaccinations began, and the primary national vaccination rate reached 70% (September 17, 2020). Despite vaccination efforts, the spread of the Delta variant (July 2021–January 2022) led to a large-scale epidemic, especially in the metropolitan region.

3) 2022–2023: Omicron variants and surge in increase confirmed cases (crisis level: “Red”→“Orange”)

In 2022 and 2023, there were 28,424,349 and 5,517,540 confirmed cases, with an incidence rates of 55,355 and 10,745 per 100,000 people, respectively. There were 25,915 and 3,213 deaths, with case fatality rates of 0.09% and 0.06%, respectively (Table 1).

The emergence of the Omicron variant in December 2021 led to an exponential increase in confirmed cases, exceeding 50% of detected cases from January 2022 onward. When comparing monthly outbreaks, the highest number of confirmed cases during the COVID-19 pandemic occurred in March 2022, with 9,959,368 confirmed cases (28.8% of the total outbreak). In April, the number of confirmed cases decreased to approximately 4,142,095, which is still a higher number of cases than before 2022. Following the March 2022 peak, the number of cases declined, with one peak in summer and winter, with 3,469,887 cases in August and 1,960,578 cases in December. In 2023, monthly cases stabilized at approximately 300,000 since February. On August 31, 2023, mandatory surveillance ended with the transition of COVID-19 to Class 4 infectious disease sentinel surveillance.

2. Basic Characteristics and Geographic Distribution of Confirmed Cases by Year

1) Demographic characteristics and routes of infection

During the entire period, individuals in their 40s accounted for the largest proportion of COVID-19 confirmed cases (5,237,546; 15.1%) and those aged 80 and older accounted for the smallest proportion (1,252,949; 3.6%). By year, the largest proportion of cases by age group was among those in their 50s in 2020 at 18.8% (11,393), followed by those in their 20s in 2021 at 14.9% (84,714), those in their 40s in 2022 at 15.3% (4,337,066), and those in their 30s in 2023 at 15.2% (836,333). By sex, female confirmed cases (18,680,325; 54.0%) outnumbered male confirmed cases (15,892,229; 46.0%), across all years except 2021. Most cases were domestic (34,492,629; 99.8%), with imported cases accounting for only 0.2% (79,925).

2) Incidence by region

By region, the highest number of cases occurred in Gyeonggi-do (9,266,797; 26.8%), followed by Seoul (6,751,335; 19.5%), and Busan (2,092,642; 6.1%) in order. By year, the largest proportion of cases (46.1% to 66.3%) occurred in Seoul and Gyeonggi-do (Tables 1, 2).

In terms of confirmed cases by region, the incidence per 100,000 people was highest in Sejong (78,778), followed by Seoul (70,818), and Gwangju (70,510), with variations by year (Table 2). In 2020, the highest numbers of cases were in Daegu (324), followed by Seoul (199) and Gyeonggi-do (109); in 2021, the highest number of cases were in Seoul (2,162), followed by Gyeonggi-do (1,300) and Incheon (1,159) in this order. In 2022, the highest numbers of cases were reported in Sejong (65,708), Gwangju (58,224), and Gyeonggi-do (58,098) in this order. In 2023, the regions with the highest incidence were Jeju-do (12,824), Sejong (12,452), and Gwangju (11,731) in this order.

COVID-19 cases and incidence rates by region
Total2020 (1.20.–)202120222023 (–8.30.)
Case
(crude incidence rate)
Standardized ratea)Case (crude incidence rate)Standardized ratea)Case
(crude incidence rate)
Standardized ratea)Case
(crude incidence rate)
Standardized ratea)Case
(crude incidence rate)
Standardized ratea)
Total34,572,554 (67,328)67,32860,722 (118)118569,943 (1,110)1,11028,424,349 (55,355)55,3555,517,540 (10,745)10,745
Seoul6,751,335 (70,818)70,47018,992 (199)199206,109 (2,162)2,1635,436,495 (57,026)56,8151,089,739 (11,431)11,293
Busan2,092,642 (62,159)62,8341,867 (55)5423,207 (689)6901,691,534 (50,245)51,032376,034 (11,170)11,058
Daegu1,516,421 (62,917)63,1437,801 (324)32215,323 (636)6381,245,690 (51,684)51,898247,607 (10,273)10,285
Incheon1,991,892 (68,166)68,1002,839 (97)9833,880 (1,159)1,1621,649,641 (56,454)56,286305,532 (10,456)10,554
Gwangju1,018,499 (70,510)70,0261,081 (75)776,945 (481)479841,026 (58,224)57,608169,447 (11,731)11,862
Daejeon1,013,275 (69,442)69,063845 (58)5811,405 (782)778836,323 (57,315)56,864164,702 (11,287)11,363
Ulsan738,128 (64,970)64,864672 (59)676,200 (546)540611,309 (53,807)53,489119,947 (10,558)10,768
Sejong273,413 (78,778)75,792149 (43)431,993 (574)558228,054 (65,708)62,34443,217 (12,452)12,848
Gyeonggi9,266,797 (70,096)69,59614,450 (109)112171,882 (1,300)1,3007,680,724 (58,098)57,4631,399,741 (10,588)10,721
Gangwon1,005,836 (65,797)67,3761,207 (79)7911,198 (733)747847,429 (55,435)56,950146,002 (9,551)9,601
Chungbuk1,075,474 (67,624)68,0111,163 (73)7210,335 (650)659900,824 (56,642)57,020163,152 (10,259)10,259
Chungnam1,390,798 (65,974)66,3031,653 (78)8016,441 (780)7891,155,658 (54,820)55,119217,046 (10,296)10,316
Jeonbuk1,167,948 (64,890)65,227837 (47)468,731 (485)496963,247 (53,517)54,010195,133 (10,841)10,675
Jeonnam1,142,483 (61,829)62,652560 (30)325,518 (299)308941,437 (50,949)51,957194,968 (10,551)10,356
Gyeongbuk1,581,207 (59,990)61,0062,424 (92)9212,890 (489)5031,311,391 (49,754)50,793254,502 (9,656)9,618
Gyeongnam2,075,991 (62,304)62,3701,325 (40)4019,351 (581)5831,712,297 (51,389)51,467343,018 (10,295)10,280
Jeju451,523 (67,667)67,117416 (62)634,222 (633)631361,316 (54,149)53,55685,569 (12,824)12,867

Unit: n (incidence per 100,000 population). COVID-19=coronavirus disease 2019. a)Age-adjusted rates (standard population: mid-year estimates of the population for 2020)..



The age-standardized incidence, calculated by standardizing the proportion of the region’s population by age, was the highest in Sejong (75,792), followed by Seoul (70,470), and Gwangju (70,026) across all years (Table 2). In 2020, the highest age-standardized incidence was in Daegu (322), followed by Seoul (199), and Gyeonggi-do (112) in order. In 2021, the highest age-standardized incidence was in Seoul (2,163), followed by Gyeonggi-do (1,300), and Incheon (1,162). In 2022, Sejong (62,344) showed the highest age-standardized incidence, followed by Gwangju (57,608), and Gyeonggi-do (57,463) in order. In 2023, Jeju-do (12,867), Sejong (12,848), and Gwangju (11,862) had the highest age-standardized incidence in that order.

3. Basic Characteristics and Geographic Incidence of Confirmed Cases by Variant Dominance Period

The number of COVID-19 confirmed cases differed across variant dominance periods, with 187,339 cases during the Delta variant pre-dominance period, 500,410 cases during the Delta variant dominance period, and 33,884,805 cases during the Omicron variant dominance period (Table 3). The average daily number of confirmed cases was 340 during the Delta variant pre-dominance period, 2,876 during the Delta variant dominance period, and 57,335 during the Omicron variant dominance period.

Characteristic of COVID-19 cases by variant dominant period
ClassTotal
(2020.1.20.–2023.8.30.)
Pre-Delta dominant period
(2020.1.20.–2021.7.24.)
Delta dominant period
(2021.7.25.–2022.1.15.)
Omicron dominant period(2022.1.16.–2023.8.30.)
Total (average daily case)34,572,554 (26,231)187,339 (340)500,410 (2,876)33,884,805 (57,335)
Age (yr)
0–93,270,282 (9.5)8,914 (4.8)47,378 (9.5)3,213,990 (9.5)
10–194,246,977 (12.3)14,407 (7.7)55,961 (11.2)4,176,609 (12.3)
20–295,001,143 (14.5)31,608 (16.9)72,070 (14.4)4,897,465 (14.5)
30–395,077,726 (14.7)27,270 (14.6)73,565 (14.7)4,976,891 (14.7)
40–495,237,546 (15.1)29,639 (15.8)71,544 (14.3)5,136,363 (15.2)
50–594,531,012 (13.1)33,776 (18.0)64,582 (12.9)4,432,654 (13.1)
60–693,898,836 (11.3)24,842 (13.3)70,267 (14.0)3,803,727 (11.2)
70–792,056,083 (5.9)10,800 (5.8)29,444 (5.9)2,015,839 (5.9)
≥801,252,949 (3.6)6,083 (3.2)15,599 (3.1)1,231,267 (3.6)
Sex
Male15,892,229 (46.0)95,427 (50.9)262,151 (52.4)15,534,651 (45.8)
Female18,680,325 (54.0)91,912 (49.1)238,259 (47.6)18,350,154 (54.2)
Transmission route
Local cases34,492,629 (99.8)172,532 (92.1)450,343 (90.0)33,196,273 (98.0)
Imported cases79,925 (0.2)14,807 (7.9)50,067 (10.0)688,532 (2.0)
Region
Metropolitan
Seoul6,751,335 (19.5)61,112 (32.6)179,580 (35.9)6,510,643 (19.2)
Incheon1,991,892 (5.8)8,423 (4.5)31,545 (6.3)1,951,924 (5.8)
Gyeonggi9,266,797 (26.8)52,791 (28.2)153,602 (30.7)9,060,404 (26.7)
Non-metropolitan
Busan2,092,642 (6.1)7,609 (4.1)20,114 (4.0)2,064,919 (6.1)
Daegu1,516,421 (4.4)11,252 (6.0)13,399 (2.7)1,491,770 (4.4)
Gwangju1,018,499 (2.9)3,232 (1.7)6,634 (1.3)1,008,633 (3.0)
Daejeon1,013,275 (2.9)3,678 (2.0)9,340 (1.9)1,000,257 (3.0)
Ulsan738,128 (2.1)3,121 (1.7)4,264 (0.9)730,743 (2.2)
Sejong273,413 (0.8)684 (0.4)1,654 (0.3)271,075 (0.8)
Gangwon1,005,836 (2.9)4,198 (2.2)9,393 (1.9)992,245 (2.9)
Chungbuk1,075,474 (3.1)3,639 (1.9)8,776 (1.8)1,063,059 (3.1)
Chungnam1,390,798 (4.0)4,618 (2.5)15,160 (3.0)1,371,020 (4.0)
Jeonbuk1,167,948 (3.4)2,613 (1.4)8,233 (1.6)1,157,102 (3.4)
Jeonnam1,142,483 (3.3)1,904 (1.0)5,557 (1.1)1,135,022 (3.3)
Gyeongbuk1,581,207 (4.6)5,269 (2.8)11,351 (2.3)1,564,587 (4.6)
Gyeongnam2,075,991 (6.0)6,532 (3.5)15,860 (3.2)2,053,599 (6.1)
Jeju451,523 (1.3)1,598 (0.9)3,279 (0.7)446,646 (1.3)
Quarantine18,892 (0.1)5,066 (2.7)2,669 (0.5)11,157 (0.03)
Severity
Deaths35,6052,1394,73328,733
Severe/critical cases38,1124,6658,29625,151
Case severity rate (%)a)0.192.972.140.15
Case fatality rate (%)a)0.101.140.950.08

Unit: n (%). COVID-19=coronavirus disease 2019. a)The case severity rate and case fatality rate were analyzed continuously observing the progress of confirmed cases during each respective period. The monitoring period includes confirmed cases up to two weeks prior (August 12th, 2023, 12 am)..



The highest incidence for each dominance period by age group was 18.0% (33,776) in their 50s during the Delta variant pre-dominance period, 14.7% (73,565) in their 30s during the Delta variant dominance period, and 15.2% (5,136,363) in their 40s during the Omicron variant dominance period. By sex, female accounted for a larger proportion of confirmed cases during all periods except the Omicron variant dominance period. As for the route of infection, imported cases accounted for 10% of cases during the Delta variant dominance period and decreased to 2% during the Omicron variant dominance period.

During the variant dominance periods, most cases (51.7% to 72.9%) occurred in the metropolitan region.

4. Severity

During the entire pandemic, the case severity rate and case fatality rate were 0.19% and 0.10%, respectively (Tables 1, 3, Figure 2). In 2020, the case severity rate was 4.33% and the case fatality rate was 2.16%, showing fluctuating trends. In 2021, the severity rate was 2.25% and the fatality rate was 0.91%, indicating an overall decrease, followed by an increase in severity in the second half of the year, when the Delta variants became dominant. By month in 2021, the case severity rate decreased steadily from 3.16% in January, began to rise in September, peaked at 3.02% in November, and then declined again. The fatality rate had the lowest rate of 0.31% in July and increased in September, peaking at 1.55% in November. From 2022 to the end of mandatory surveillance in 2023, the severity rate and fatality rate decreased substantially as the Omicron variants became dominant. By 2022, the severity and fatality rates were 0.14% and 0.09%, respectively, while in 2023, they were 0.15% and 0.06%, respectively.

Figure 2. Monthly COVID-19 case severity rate and case fatality rate
COVID-19=coronavirus disease 2019.

During the entire COVID-19 pandemic, both severity and fatality rates were highest in 2020 (4.33% and 2.16%, respectively). After 2022, the severity rate remained consistently low at 0.14%, and the fatality rate reached its lowest point of 0.06% in 2023. By variant dominance period, death and severe/critical condition cases were highest during the Omicron variant dominance period (28,733 and 25,151, respectively), while the severity and fatality rates were highest during the Delta variant pre-dominance period (2.97% and 1.14%, respectively).

Discussion

The present report analyzed COVID-19 data reported to the KDCA from January 20, 2020 to August 30, 2023, covering the mandatory surveillance period of COVID-19 infection, thereby investigating the outbreak trends and characteristics.

In 2020 and 2021, confirmed cases of COVID-19 gradually increased. After January 2022 corresponding to the Omicron variant dominance period, there was an rapidly rise in cases in 2022, accounting for 82.2% of all confirmed cases during the entire surveillance period. In particular, March 2022 recorded the highest monthly number of confirmed cases at 9,959,368. The average daily case was highest during the Omicron variant dominance period, which included 57,335 cases. By age group, the proportion of confirmed cases during the mandatory surveillance period was highest in those in their 40s (15.1%), 30s (14.7%), and 20s (14.5%), who are more socially active. Variations in age proportions by year were 1.1% (14.2–15.3%) in their 40s, 2.1% (13.9–16.0%) in their 20s, 2.2% (3.1–5.3%) in their 80s and older, and 2.5% (12.7–15.2%) in their 30s, compared to 7.0% (3.4–10.4%) in those aged 9 and under, 6.5% (6.2–12.7%) in their 10s, 5.9% (12.9–18.8%) in their 50s, and 5.1% (10.7–15.8%) in their 60s, indicating that the occurence of COVID-19 was different between younger and older age groups at different times. In addition, the proportion of confirmed cases in the metropolitan region compared to the whole country was 59.7% in 2020, 72.3% in 2021, 52.0% in 2022, and 50.7% in 2023. These were higher than the proportion of the population in the metropolitan region (50%), suggesting a disproportionately higher number of confirmed cases in this region.

Severity was highest in the early stages of the pandemic, fluctuated over time, and began decreasing consistently from 2021 onwards. This could be attributed to the stabilization of the COVID-19 response system and the start of COVID-19 vaccination as the COVID-19 pandemic continued [9]. However, the second half of 2021 saw an increase in severity and fatality rates with the emergence of the Delta variant. In 2022, the severity rate declined significantly with the emergence of the Omicron variants, which demonstrated higher transmissibility but lower severity compared to previous variants [10]. In addition, COVID-19 was regarded as a manageable disease due to continued vaccination, treatment, and other measures, leading to changes in the monitoring system in 2023.

When comparing COVID-19 outbreaks by year and variant dominance, temporal categorization revealed some differences. However, adopting a multifaceted approach in future analyses could provide more comprehensive insights by considering diverse influencing factors beyond time periods.

Using the information collected during the mandatory surveillance of COVID-19, the KDCA produced statistics and publicized them through press releases to monitor the daily outbreak situation. Moreover, this information served as a basis for research on risk assessment for outbreaks, forecasting to establish response strategies, and risk factor analysis. Since confirmed case reports were influenced by quarantine policies, healthcare systems, COVID-19 variants, and non-pharmaceutical interventions such as vaccination, it is important to interpret trends with caution while considering these factors. Therefore, further analysis is recommended to account for the impact of various interventions, as this could provide a foundation for preparing for future infectious disease crises.

Declarations

Ethics Statement: Not applicable.

Funding Source: None.

Acknowledgments: We would like to thank regional centers for Disease Control and Prevention, local governments and healthcare facilities for investigation of COVID-19 deaths.

Conflict of Interest: Sun-kyung Baek is an editorial board member of the journal, but was not involved in the review process of this manuscript. Otherwise, there is no conflict of interest to declare.

Author Contributions: Conceptualization: GHK, BYR, SKB. Data curation: GHK, SJJ. Formal analysis: GHK, BYR. Investigation: GHK, BYR, SJJ. Methodology: GHK, BYR. Project administration: BYR, SKB. Resources: GHK, SJJ. Software: GHK, BYR, SJJ. Supervision: SKB. Validation: BYR, SKB. Visualization: GHK, BYR. Writing – original draft: GHK. Writing – review & editing: BYR, SKB..

Fig 1.

Figure 1.Weekly and monthly trends in COVID-19 cases (January 20, 2020–August 30, 2023)
(A) Trends in weekly confirmed and cumulative COVID-19 cases by week (January 20, 2020–August 30, 2023). (B) Trends in monthly confirmed and cumulative COVID-19 cases by month. COVID-19=coronavirus disease 2019; Jan=January; W=week; Apr=April; Jun=June; Aug=August; Oct=October; Mar=March; Dec=December; Jul=July; Feb=February.
Public Health Weekly Report 2025; 18: 157-179https://doi.org/10.56786/PHWR.2025.18.4.1

Fig 2.

Figure 2.Monthly COVID-19 case severity rate and case fatality rate
COVID-19=coronavirus disease 2019.
Public Health Weekly Report 2025; 18: 157-179https://doi.org/10.56786/PHWR.2025.18.4.1
Characteristic of COVID-19 cases by year
ClassTotal
(2020.1.20.–2023.8.30.)
2020 (1.20.–)202120222023 (–8.30.)
Total34,572,55460,722569,94328,424,3495,517,540
Age (yr)
0–93,270,282 (9.5)2,091 (3.4)47,042 (8.3)2,967,570 (10.4)253,579 (4.6)
10–194,246,977 (12.3)3,769 (6.2)59,269 (10.4)3,603,042 (12.7)580,897 (10.5)
20–295,001,143 (14.5)9,708 (16.0)84,714 (14.9)4,141,840 (14.6)764,881 (13.9)
30–395,077,726 (14.7)7,726 (12.7)83,946 (14.7)4,149,721 (14.6)836,333 (15.2)
40–495,237,546 (15.1)8,621 (14.2)83,495 (14.6)4,337,066 (15.3)808,364 (14.7)
50–594,531,012 (13.1)11,393 (18.8)80,146 (14.1)3,680,898 (12.9)758,575 (13.7)
60–693,898,836 (11.3)9,624 (15.8)80,209 (14.1)3,050,649 (10.7)758,354 (13.7)
70–792,056,083 (5.9)4,768 (7.9)33,643 (5.9)1,553,122 (5.5)464,550 (8.4)
≥801,252,949 (3.6)3,022 (5.0)17,479 (3.1)940,441 (3.3)292,007 (5.3)
Sex
Male15,892,229 (46.0)29,597 (48.7)298,520 (52.4)13,156,843 (46.3)2,407,269 (43.6)
Female18,680,325 (54.0)31,125 (51.3)271,423 (47.6)15,267,506 (53.7)3,110,271 (56.4)
Transmission route
Local cases34,492,629 (99.8)55,343 (91.1)557,985 (97.9)28,368,494 (99.8)5,510,807 (99.9)
Imported cases79,925 (0.2)5,379 (8.9)11,958 (2.1)55,855 (0.2)6,733 (0.1)
Region
Metropolitan
Seoul6,751,335 (19.5)18,992 (31.3)206,109 (36.2)5,436,495 (19.1)1,089,739 (19.8)
Incheon1,991,892 (5.8)2,839 (4.7)33,880 (5.9)1,649,641 (5.8)305,532 (5.5)
Gyeonggi9,266,797 (26.8)14,450 (23.8)171,882 (30.2)7,680,724 (27.0)1,399,741 (25.4)
Non-metropolitan
Busan2,092,642 (6.1)1,867 (3.1)23,207 (4.1)1,691,534 (6.0)376,034 (6.8)
Daegu1,516,421 (4.4)7,801 (12.8)15,323 (2.7)1,245,690 (4.4)247,607 (4.5)
Gwangju1,018,499 (2.9)1,081 (1.8)6,945 (1.2)841,026 (3.0)169,447 (3.1)
Daejeon1,013,275 (2.9)845 (1.4)11,405 (2.0)836,323 (2.9)164,702 (3.0)
Ulsan738,128 (2.1)672 (1.1)6,200 (1.1)611,309 (2.2)119,947 (2.2)
Sejong273,413 (0.8)149 (0.2)1,993 (0.3)228,054 (0.8)43,217 (0.8)
Gangwon1,005,836 (2.9)1,207 (2.0)11,198 (2.0)847,429 (3.0)146,002 (2.6)
Chungbuk1,075,474 (3.1)1,163 (1.9)10,335 (1.8)900,824 (3.2)163,152 (3.0)
Chungnam1,390,798 (4.0)1,653 (2.7)16,441 (2.9)1,155,658 (4.1)217,046 (3.9)
Jeonbuk1,167,948 (3.4)837 (1.4)8,731 (1.5)963,247 (3.4)195,133 (3.5)
Jeonnam1,142,483 (3.3)560 (0.9)5,518 (1.0)941,437 (3.3)194,968 (3.5)
Gyeongbuk1,581,207 (4.6)2,424 (4.0)12,890 (2.3)1,311,391 (4.6)254,502 (4.6)
Gyeongnam2,075,991 (6.0)1,325 (2.2)19,351 (3.4)1,712,297 (6.0)343,018 (6.2)
Jeju451,523 (1.3)416 (0.7)4,222 (0.7)361,316 (1.3)85,569 (1.6)
Quarantine18,892 (0.1)2,441 (4.0)4,313 (0.8)9,954 (0.04)2,184 (0.04)
Severity
Deaths35,6051,3135,16425,9153,213
Severe/critical cases38,1122,00610,38220,0235,701
Case severity rate (%)a)0.194.332.250.140.15
Case fatality rate (%)a)0.102.160.910.090.06

Unit: n (%). COVID-19=coronavirus disease 2019. a)The case severity rate and case fatality rate were analyzed continuously observing the progress of confirmed cases during each respective period. The monitoring period includes confirmed cases up to two weeks prior (August 12th, 2023, 12 am)..


COVID-19 cases and incidence rates by region
Total2020 (1.20.–)202120222023 (–8.30.)
Case
(crude incidence rate)
Standardized ratea)Case (crude incidence rate)Standardized ratea)Case
(crude incidence rate)
Standardized ratea)Case
(crude incidence rate)
Standardized ratea)Case
(crude incidence rate)
Standardized ratea)
Total34,572,554 (67,328)67,32860,722 (118)118569,943 (1,110)1,11028,424,349 (55,355)55,3555,517,540 (10,745)10,745
Seoul6,751,335 (70,818)70,47018,992 (199)199206,109 (2,162)2,1635,436,495 (57,026)56,8151,089,739 (11,431)11,293
Busan2,092,642 (62,159)62,8341,867 (55)5423,207 (689)6901,691,534 (50,245)51,032376,034 (11,170)11,058
Daegu1,516,421 (62,917)63,1437,801 (324)32215,323 (636)6381,245,690 (51,684)51,898247,607 (10,273)10,285
Incheon1,991,892 (68,166)68,1002,839 (97)9833,880 (1,159)1,1621,649,641 (56,454)56,286305,532 (10,456)10,554
Gwangju1,018,499 (70,510)70,0261,081 (75)776,945 (481)479841,026 (58,224)57,608169,447 (11,731)11,862
Daejeon1,013,275 (69,442)69,063845 (58)5811,405 (782)778836,323 (57,315)56,864164,702 (11,287)11,363
Ulsan738,128 (64,970)64,864672 (59)676,200 (546)540611,309 (53,807)53,489119,947 (10,558)10,768
Sejong273,413 (78,778)75,792149 (43)431,993 (574)558228,054 (65,708)62,34443,217 (12,452)12,848
Gyeonggi9,266,797 (70,096)69,59614,450 (109)112171,882 (1,300)1,3007,680,724 (58,098)57,4631,399,741 (10,588)10,721
Gangwon1,005,836 (65,797)67,3761,207 (79)7911,198 (733)747847,429 (55,435)56,950146,002 (9,551)9,601
Chungbuk1,075,474 (67,624)68,0111,163 (73)7210,335 (650)659900,824 (56,642)57,020163,152 (10,259)10,259
Chungnam1,390,798 (65,974)66,3031,653 (78)8016,441 (780)7891,155,658 (54,820)55,119217,046 (10,296)10,316
Jeonbuk1,167,948 (64,890)65,227837 (47)468,731 (485)496963,247 (53,517)54,010195,133 (10,841)10,675
Jeonnam1,142,483 (61,829)62,652560 (30)325,518 (299)308941,437 (50,949)51,957194,968 (10,551)10,356
Gyeongbuk1,581,207 (59,990)61,0062,424 (92)9212,890 (489)5031,311,391 (49,754)50,793254,502 (9,656)9,618
Gyeongnam2,075,991 (62,304)62,3701,325 (40)4019,351 (581)5831,712,297 (51,389)51,467343,018 (10,295)10,280
Jeju451,523 (67,667)67,117416 (62)634,222 (633)631361,316 (54,149)53,55685,569 (12,824)12,867

Unit: n (incidence per 100,000 population). COVID-19=coronavirus disease 2019. a)Age-adjusted rates (standard population: mid-year estimates of the population for 2020)..


Characteristic of COVID-19 cases by variant dominant period
ClassTotal
(2020.1.20.–2023.8.30.)
Pre-Delta dominant period
(2020.1.20.–2021.7.24.)
Delta dominant period
(2021.7.25.–2022.1.15.)
Omicron dominant period(2022.1.16.–2023.8.30.)
Total (average daily case)34,572,554 (26,231)187,339 (340)500,410 (2,876)33,884,805 (57,335)
Age (yr)
0–93,270,282 (9.5)8,914 (4.8)47,378 (9.5)3,213,990 (9.5)
10–194,246,977 (12.3)14,407 (7.7)55,961 (11.2)4,176,609 (12.3)
20–295,001,143 (14.5)31,608 (16.9)72,070 (14.4)4,897,465 (14.5)
30–395,077,726 (14.7)27,270 (14.6)73,565 (14.7)4,976,891 (14.7)
40–495,237,546 (15.1)29,639 (15.8)71,544 (14.3)5,136,363 (15.2)
50–594,531,012 (13.1)33,776 (18.0)64,582 (12.9)4,432,654 (13.1)
60–693,898,836 (11.3)24,842 (13.3)70,267 (14.0)3,803,727 (11.2)
70–792,056,083 (5.9)10,800 (5.8)29,444 (5.9)2,015,839 (5.9)
≥801,252,949 (3.6)6,083 (3.2)15,599 (3.1)1,231,267 (3.6)
Sex
Male15,892,229 (46.0)95,427 (50.9)262,151 (52.4)15,534,651 (45.8)
Female18,680,325 (54.0)91,912 (49.1)238,259 (47.6)18,350,154 (54.2)
Transmission route
Local cases34,492,629 (99.8)172,532 (92.1)450,343 (90.0)33,196,273 (98.0)
Imported cases79,925 (0.2)14,807 (7.9)50,067 (10.0)688,532 (2.0)
Region
Metropolitan
Seoul6,751,335 (19.5)61,112 (32.6)179,580 (35.9)6,510,643 (19.2)
Incheon1,991,892 (5.8)8,423 (4.5)31,545 (6.3)1,951,924 (5.8)
Gyeonggi9,266,797 (26.8)52,791 (28.2)153,602 (30.7)9,060,404 (26.7)
Non-metropolitan
Busan2,092,642 (6.1)7,609 (4.1)20,114 (4.0)2,064,919 (6.1)
Daegu1,516,421 (4.4)11,252 (6.0)13,399 (2.7)1,491,770 (4.4)
Gwangju1,018,499 (2.9)3,232 (1.7)6,634 (1.3)1,008,633 (3.0)
Daejeon1,013,275 (2.9)3,678 (2.0)9,340 (1.9)1,000,257 (3.0)
Ulsan738,128 (2.1)3,121 (1.7)4,264 (0.9)730,743 (2.2)
Sejong273,413 (0.8)684 (0.4)1,654 (0.3)271,075 (0.8)
Gangwon1,005,836 (2.9)4,198 (2.2)9,393 (1.9)992,245 (2.9)
Chungbuk1,075,474 (3.1)3,639 (1.9)8,776 (1.8)1,063,059 (3.1)
Chungnam1,390,798 (4.0)4,618 (2.5)15,160 (3.0)1,371,020 (4.0)
Jeonbuk1,167,948 (3.4)2,613 (1.4)8,233 (1.6)1,157,102 (3.4)
Jeonnam1,142,483 (3.3)1,904 (1.0)5,557 (1.1)1,135,022 (3.3)
Gyeongbuk1,581,207 (4.6)5,269 (2.8)11,351 (2.3)1,564,587 (4.6)
Gyeongnam2,075,991 (6.0)6,532 (3.5)15,860 (3.2)2,053,599 (6.1)
Jeju451,523 (1.3)1,598 (0.9)3,279 (0.7)446,646 (1.3)
Quarantine18,892 (0.1)5,066 (2.7)2,669 (0.5)11,157 (0.03)
Severity
Deaths35,6052,1394,73328,733
Severe/critical cases38,1124,6658,29625,151
Case severity rate (%)a)0.192.972.140.15
Case fatality rate (%)a)0.101.140.950.08

Unit: n (%). COVID-19=coronavirus disease 2019. a)The case severity rate and case fatality rate were analyzed continuously observing the progress of confirmed cases during each respective period. The monitoring period includes confirmed cases up to two weeks prior (August 12th, 2023, 12 am)..


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