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Korea experiences significant rise in influenza cases this flu season

Published: 04 Nov. 2025, 10:28

An employee checks the stock of Covid-19 and flu vaccines at the Buk District Public Health Center in Gwangju on Oct. 29. [GWANGJU BUK DISTRICT OFFICE]

Korea is facing a sharp rise in influenza cases, with infections at the end of October more than tripling compared to last year, raising concerns among health officials of one of the worst flu seasons in the past decade.

Surveillance data from clinics showed that the influenza-like illness (ILI) rate reached 13.6 cases per 1,000 outpatients during the 43rd week of the year, from Oct. 19 to 25, according to the Korea Disease Control and Prevention Agency (KDCA). That figure was 3.5 times higher than the same period last year, when it stood at 3.9.

Influenza-like illness refers to patients who have a fever of at least 38 degrees Celsius (100 degrees Fahrenheit) along with symptoms such as cough and sore throat.

By age group, the ILI rate was highest among children aged 7 to 12, with 31.6 cases per 1,000 outpatients. They were followed by those aged 1 to 6 with 25.8 cases, infants under 1 with 16.4, teenagers aged 13 to 18 with 15.8, and adults aged 19 to 49 with 11.8.

The influenza virus detection rate from respiratory samples collected at clinics reached 11.6 percent in Week 43, up 4.3 percentage points from the previous week. The dominant strain was influenza A (H3N2), with no mutations found that could affect antiviral resistance.

At hospitals, 221 medical institutions reported a total of 98 flu-related hospitalizations during the same week — 7.5 times higher than the 13 cases recorded in the same period last season.

A child receives a flu vaccination at an otolaryngology clinic in Seodaemun District, western Seoul, on Oct. 22, as a nationwide influenza alert remains in effect. [YONHAP]

The KDCA said that given the current rise in cases compared to October last year and trends observed in the Southern Hemisphere, the 2025–26 flu season could be similar in scale to the 2024–25 season, which saw the highest level of flu activity in the past decade. The agency also warned that this year’s flu season may last longer.

"This season’s flu outbreak started about two months earlier than last year," said Hong Jeong-ik, head of the KDCA’s infectious disease policy bureau. "We believe there is a possibility that influenza will spread as widely as it did last winter."

In response, the agency urged eligible groups — seniors aged 65 or older, pregnant women and children aged six months to 13 years — to participate in the national vaccination program.

Approximately 6.58 million seniors, or 60.5 percent, and 1.89 million children, or 40.5 percent, had received their flu shots as of 6 p.m. last Friday, according to the KDCA.

"There is a strong possibility that influenza will spread widely again this winter, so thorough preparation is needed," said Lim Seung-kwan, commissioner of the KDCA. "We urge high-risk groups to get vaccinated before the peak of flu season."

This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.
BY HYEON YE-SEUL [[email protected]]