B형 인플루엔자 확산: 소아·청소년 주의보 – 한국AI부동산신문

After a period of relative calm, influenza is surging again, and a specific strain is raising concerns. Health authorities are observing a distinct rise in cases of influenza B, particularly among children and adolescents.

According to the latest data from the Disease Management and Prevention Agency, as of the second week of January 2026, the number of outpatient visits for influenza-like illness reached 40.9 per 1,000 people. This represents an increase from the previous week’s 36.4 and significantly exceeds the seasonal threshold of 9.1. The trend marks a reversal of the gradual decline seen in mid-November of last year.

Influenza-like illness is defined as a fever of 38°C (100.4°F) or higher accompanied by either cough or sore throat. Over the past four weeks, numbers have fluctuated: 39.1 in week 51 of 2025, 37.5 in week 52, 36.4 in week 1 of 2026, and then a jump to 40.9 in week 2.

Age-Specific Trends and the Rise of Flu B

The data reveals a disproportionate impact on school-aged children and teenagers. The highest incidence rate is observed in the 7-12 age group (127.2 per 1,000), followed by 13-18 year olds (97.2 per 1,000). Rates are also significant in younger children (1-6 years: 51.0) and young adults (19-49 years: 44.2). While rates are lower in those 65 and older (9.0), this population remains vulnerable due to weakened immune systems.

A crucial shift is occurring in the dominant viral strains. Analysis of respiratory samples collected from outpatient clinics shows a rapid increase in the proportion of influenza B viruses. While the overall detection rate of influenza viruses was 33.5% (a slight decrease from the previous week), the percentage of B-type viruses has soared from 0.5% in week 51 of 2025 to 17.6% in week 2 of 2026. Conversely, the prevalence of influenza A viruses has been declining.

Vaccine Effectiveness and Urgent Recommendations

Health officials are reassuring the public that the currently circulating influenza B viruses closely match the strains recommended for this season’s vaccine. Furthermore, there is no evidence of significant antiviral resistance. This suggests that vaccination remains a highly effective preventative measure.

“We are seeing a faster spread of influenza B than typically observed during late winter or early spring,” explains Dr. Seung-kwan Im, head of the Disease Management and Prevention Agency. “Even individuals who were previously infected with influenza A earlier in the season can be reinfected with influenza B, making vigilance crucial.”

Pro Tip: Don’t assume prior infection provides protection against all influenza strains. Annual vaccination is the best defense.

Authorities strongly urge individuals in high-risk groups – those 65 and older, children, and pregnant women – who haven’t yet been vaccinated to do so without delay.

Preventative Measures: A Multi-Layered Approach

Beyond vaccination, public health officials are reiterating the importance of basic preventative measures. These include frequent handwashing, covering coughs and sneezes with the elbow, wearing masks when experiencing respiratory symptoms, and ensuring adequate ventilation of indoor spaces.

For children and adolescents, schools and families play a vital role in reinforcing these practices and discouraging attendance when symptomatic.

The Disease Management and Prevention Agency continues to monitor the situation closely through a multi-layered surveillance system and provides updated statistics on its Infectious Disease Portal.

The influenza season is far from over. With the increasing prevalence of influenza B, vaccination and adherence to preventative measures are not merely personal choices, but essential contributions to community safety.

Did you know? Influenza viruses constantly evolve. That’s why annual vaccination is necessary to ensure the vaccine provides protection against the most current strains.