Press Release

Infectious Disease Trends in 2024: What Drove the Surge? KDCA Releases Analysis of Notifiable Infectious Disease Trends – Infectious disease cases up 54.5% year-on-year in 2024

- KDCA publishes the 2024 Annual Report on Notified Infectious Diseases in Korea based on data from the Infectious Disease Information System (IDIS).

- The surge in cases in 2024 was driven by outbreaks of respiratory infections, such as pertussis, particularly among children and adolescents.

- Cases of pertussis, scarlet fever, varicella, and CRE infections rosed, whereas those of mumps, tuberculosis, and viral hepatitis C and A declined.

Osong, 3 July 2025 – The Korea Disease Control and Prevention Agency (KDCA) has published the 2024 Annual Report on Notified Infectious Diseases in Korea, which analyzes trends in notifiable infectious diseases reported nationwide over the past year through the Infectious Disease Information System (IDIS) (formerly the National Infectious Disease Surveillance System). 

The annual report includes statistics on 89 notifiable infectious diseases (Classes 1 to 4) as defined under Article 2 of the Infectious Disease Control and Prevention Act. Among 66 diseases under routine comprehensive surveillance (Classes 1 to 3), 40 were reported in 2024, while 26 had no reported cases.

In 2024, a total of 168,586 cases of notifiable infectious diseases (Classes 1 to 3) were reported (329 cases per 100,000 population), marking a 54.5% increase (+59,499 cases) compared to the previous year (109,087 cases). This figure excludes COVID-19 (5,517,540 cases) and syphilis (2,790 cases), both of which were reclassified between 2023 and 2024. 

* Note: COVID-19 was reclassified from Class 2 to Class 4 in August 2023, while syphilis moved from Class 4 to Class 3 in January 2024.

< Reported Infectious Diseases Over the Past 3 Years >

(Unit :cases)

		2022	2023	2024
Total	Total	28,517,179	5,626,627	171,376
		(4,160.40%)	(-80.3%)	(-97.0)
	Excl. Covid-19 and Syphilis	92,830	109,087	168,586
		(-6.6%)	(17.5%)	(54.5)
Class 1 Infectious Disease	Subtotal	-	1	-
		(Decrease)	(Increase)	(Decrease)
Class 2 Infectious Disease	Subtotal	28,499,681	5,610,190	152,586
		(35,254.1%)	(-80.3%)	(-97.3)
	Excl. Covid-19	75,332	92,650	152,586
		(-6.5%)	(23.0%)	(64.7%)
Class 3 Infectious Disease	Subtotal	17,498	16,436	18,790
		(-6.9)	(-6.1%)	(14.3%)
	Excl. Syphilis	17,498	16,436	16,000
		(-6.9)	(-6.1)	(-2.7%)

The following outlines the major trends by disease classification in 2024:

No cases were reported among Class 1 infectious diseases (17 types) in 2024. In contrast, one case of botulism had been reported in 2023.

There were 152,586 reported cases of Class 2 infectious diseases (21 types), up 64.7% (+59,936 cases) from 2023. The significant rise was largely driven by pertussis, followed by scarlet fever, varicella, and Carbapenem-Resistant Enterobacteriaceae (CRE) infections. Together, these four diseases accounted for 84.5% (128,929 cases) of all Class 2 cases.

In particular, respiratory infection cases such as pertussis and scarlet fever saw a sharp increase, especially among children and adolescents. 

Meanwhile, cases of several Class 2 diseases—including mumps, tuberculosis, and viral hepatitis A—decreased.

Class 3 infectious diseases (28 types) totaled 18,790 reported cases in 2024, indicating a 14.3% uptick (+2,354 cases) year-on-year. However, excluding syphilis (2,790 cases), which was reclassified as a Class 3 disease in 2024, the total actually declined by 2.7% (–436 cases). Scrub typhus was the leading contributor to the increase within this category, with reported cases rising by 10.7% to 6,268 (+605 cases).

Viral hepatitis C cases recorded the largest decrease, with 6,444 cases reported in 2024, an 11.1% decline (–805 cases) compared to 2023, continuing a downward trend since its peak in 2020 (11,850 cases).

Reports of imported infectious diseases also rose significantly, with a 55.8% year-on-year increase (+217 cases). Dengue fever accounted for the largest share at 32.3% (196 cases), followed by primary syphilis at 9.7% (117 cases), malaria at 8.9% (54 cases), varicella at 7.1% (43 cases), and viral hepatitis C at 6.8% (41 cases).

The majority of imported cases (79.5%) originated from Asia, particularly countries such as Indonesia, the Philippines, Vietnam, and Thailand. Africa (e.g., South Sudan) represented 9.1% of imported cases, followed by Europe at 5.1%.

In 2024, there were a total of 1,238 deaths caused by notifiable infectious diseases, excluding tuberculosis, reflecting an 18.2% rise (+191 deaths) from the previous year (1,047 deaths).

* Note: The number of deaths from tuberculosis in 2024 is an official national statistic and will be released in late September 2025 by Statistics Korea's Cause of Death Statistics.

To enhance the timeliness and efficiency of infectious disease response, KDCA launched the Infectious Disease Information System (IDIS) in January 2024, replacing the previous National Infectious Disease Surveillance System. Since its rollout, medical institutions, public health centers, and local governments have actively used the system to report cases. 

Over the past year, this has enabled KDCA to ensure stable collection and monitoring. The surveillance data are now publicly accessible via the Infectious Disease Portal through various resources such as the Infectious Disease Dashboard, statistical summaries, and weekly outbreak trend reports. 

* Note: Class 1 to Class 3infectious diseases under mandatory surveillance are updated daily, while Class 4 infectious diseases under sentinel surveillance are tracked weekly.

< Infectious Disease Reporting System and Public Disclosures Process >

KDCA Commissioner Dr. Youngmee Jee emphasized the critical role of healthcare providers in disease surveillance, stating, “Reporting infectious diseases is the first and most crucial step in our surveillance system. Timely reporting helps us detect outbreaks early and prevent wider transmission in the community.” 

She added, “We sincerely thank the medical institutions nationwide for their diligent reporting, and the local governments for their ongoing work in epidemiological investigations, patient management, and pathogen surveillance.”