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Number of flu patients doubles in one week

Published: 14 Nov. 2025, 14:04

Children and parents are seen waiting for flu vaccinations at a hopsital in Seongbuk District, northern Seoul, on Nov. 11. [YONHAP]

Flu infections are surging among children and adolescents across Korea, with the number of patients showing flu-like symptoms doubling in just one week.

Experts warn that if the current pace continues, this winter could see the worst flu outbreak since 2016. Consequently, they are urging the public to get vaccinated.

A total of 50.7 out of every 1,000 outpatients who visited 300 designated clinics nationwide from Nov. 2 to Saturday reported flu symptoms, including a fever of over 38 degrees Celsius (100 degrees Fahrenheit), sore throat and cough, according to the Korea Disease Control and Prevention Agency (KDCA) on Friday. This marks a 122.4 percent increase from the previous week.

Flu cases have nearly doubled each week for the past month — from 7.9 cases per 1,000 outpatients in the 42nd week to 13.6 in the 43rd, 22.8 in the 44th and over 50 in the 45th week.

As a result, Korea’s flu alert level has been raised from “moderate” to “high,” with the current infection rate exceeding the seasonal epidemic threshold of 9.1 by more than fivefold.

The surge is especially sharp among those aged 18 and under. Children aged seven to 12 reported 138.1 flu-like cases per 1,000 outpatients — more than double the previous week's 68.4. For children aged one to six, the rate rose from 40.6 to 82.1. Among teenagers aged 13 to 18, the number jumped from 34.4 to 75.6.

A health worker examines Covid-19 and flu vaccines at a hospital in Gwangju on Oct. 29. [YONHAP]

Hospitalizations have also increased. Surveillance data from 221 hospitals show that 356 people were admitted with flu-like symptoms last week, up from 174 the week prior — another twofold increase.

This season's flu outbreak began nearly two months earlier than last year's, when flu activity peaked in January and hit the highest level in eight years. At this time last year, the number of flu-like cases was four per 1,000, making this year's rate more than 12 times higher.

Experts now fear this winter's flu wave could surpass last year's and become the most severe since 2016.

“This season could be one of the biggest flu outbreaks we’ve seen,” said Park Yoon-seon, an infectious disease specialist at Gachon University Gil Medical Center. “It’s already widespread now, but as the weather gets colder and drier in December and January, respiratory viruses including the flu will spread even faster.”

A child receives a flu vaccine at a hopsital in Seongbuk District, northern Seoul, on Oct. 2. [YONHAP]

The KDCA is urging people, especially those at high risk, to get vaccinated as soon as possible. Free flu shots are available for adults aged 65 and older, pregnant women and children aged six months to 13 years. Older adults are also eligible for free Covid-19 vaccines, which can be administered at the same time.

“If you haven’t received a flu shot yet, it’s not too late,” Park said. “It takes two to four weeks for antibodies to form, so getting vaccinated now will help protect you as the outbreak worsens.”

Park added that high-risk groups, including older adults and children, should all be vaccinated.

“Simultaneous vaccination for flu and Covid-19 is recommended for older adults,” she said.

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 RHEE ESTHER, KWON SUN-MI [[email protected]]