Last year, the number of cases of legally designated infectious diseases in Korea fell by more than 20% from the year before. Whooping cough, which saw a large outbreak after COVID-19, dropped sharply, and scrub typhus and chickenpox also declined. In contrast, carbapenem-resistant Enterobacterales (CRE) infections, which occur mainly among older adults, and scarlet fever, a childhood infectious disease, increased.
The Korea Disease Control and Prevention Agency said on the 28th it published the 2025 annual report on infectious disease notifications.
According to the annual report, there were a total of 139,368 reported patients with legally designated infectious diseases under complete enumeration surveillance (grades 1–3) last year. That is 272 per 100,000 people, a 20.3% decrease from 174,908 (341 per 100,000) a year earlier.
There are 90 legally designated infectious diseases in total. Of these, 67 are under complete enumeration surveillance and 23 are under sentinel surveillance. Last year, 41 of the 67 diseases under complete enumeration surveillance were reported, while the remaining 26 had no reported cases.
Whooping cough led the decline. Whooping cough experienced a large-scale outbreak in 2024 due to factors such as the lifting of social distancing after COVID-19, but 5,491 cases were reported last year, an 88.6% plunge from 48,048 the year before.
Chickenpox totaled 30,248, down 5.2% from the previous year, and scrub typhus, a grade 3 infectious disease, was 3,405, a 45.7% decrease year over year. Scrub typhus is an illness that causes high fever and headache after being bitten by the larvae of chigger mites. The agency noted that including the presence of eschar (scab) formation in the reporting criteria to more accurately determine infection status recently likely contributed to the drop in reports.
Some infectious diseases, however, increased. CRE infections totaled 49,053 last year, up 15.8% from a year earlier, and scarlet fever surged 97.4% to 13,113.
CRE infection refers to infection with bacteria resistant to carbapenem antibiotics. Because of its high fatality rate among people with weakened immunity, it is designated as a grade 2 infectious disease in Korea.
In particular, 86.5% of CRE patients were among those 60 and older. For scarlet fever, 86.8% of all patients were children ages 0–9, showing a pronounced age concentration.
Legionellosis and severe fever with thrombocytopenia syndrome (SFTS) also increased by 41.6% and 64.7%, respectively. The agency analyzed that the rise in legionellosis was influenced by the aging of artificial water systems and the growing older population, while the rise in SFTS was affected by early heat, rising average temperatures, and increased outdoor activities that expand the risk of tick exposure.
There were 633 imported infectious disease cases last year. Imported infectious diseases, which had risen to 56,037 in 2022 during the COVID-19 outbreak, have recently stabilized to pre-COVID-19 levels.
Among imported infectious diseases, dengue fever was the most common with 110 cases (17.4%). It was followed by primary syphilis with 74 (11.7%), malaria with 56 (8.8%), and measles and latent syphilis with 55 each (8.7%). Asia, including Vietnam, the Philippines, Indonesia, Thailand, and China, accounted for 81.4% of infection regions.
Im Seung-kwan, commissioner of the Korea Disease Control and Prevention Agency, said, "Infectious disease notification is the very first step in recognizing transmission and preventing its spread," adding, "Based on notification data, we will strengthen our analysis, risk assessment, and forecasting functions to respond proactively to outbreaks."