The incidence of suspected influenza (flu) cases surged to a five-year high in the second week of December in Korea, particularly impacting children and adolescents, the Korean health authorities said on Friday. 

According to the Korea Disease Control and Prevention Agency (KDCA), the rate of patients exhibiting symptoms suggestive of influenza per 1,000 outpatient visits on Dec. 3-9 stood at 61.3, up 26.1 percent from the previous week. 

This marks the highest figure in five years since 2019. The previous peak was 60.7 in the final week of December 2023. 

The surge in influenza cases was particularly pronounced among elementary, middle, and high school students.

The number of teenage patients aged 13-18 per 1,000 outpatients was 133.4, which was 20.5 times greater than the 2023-2024 seasonal flu epidemic threshold of 6.5 per 1,000 outpatients, the KDCA data showed. The figure among those aged 7-12 was 120.1, 18.5 times higher than the epidemic threshold. 

In the second week of December, inpatient sampling surveillance conducted at 218 hospitals revealed 1,047 influenza hospitalizations, marking a 31.4 percent increase compared to the previous week's figure of 797.

Among the hospitalized, older adults aged 65 or more accounted for 40.3 percent. 

The KDCA strongly recommended vaccination for individuals in specific demographic groups, including children aged 6 months to 13 years, pregnant women, and those aged 65 years and older because these populations are at a heightened risk of experiencing complications from influenza, such as pneumonia.

"Personal hygiene practices such as proper handwashing, cough etiquette, and wearing a mask should be followed," said KDCA Commissioner Jee Young-mee. "In spaces where people live together, such as kindergartens and daycare centers, limit the sharing of utensils, towels, and toys, and monitor children for respiratory symptoms so that they can visit a medical institution on time."

The KDCA said it was mulling additional stockpiling efforts following the release of 315,000 doses of antiviral drugs, including Tamiflu, in November.

Meanwhile, the number of hospitalized patients for mycoplasma pneumonia, a condition that has been spreading in China and is concerning as a potential domestic epidemic, has shown signs of stabilization, experiencing a slight decrease from the previous week. In the second week of December, the count of hospitalized patients dropped to 222 from 258 the previous week.