Flu (Influenza)
Symptoms of influenza, treatment options (Tamiflu), and vaccination schedule.
Differences from a cold.
Influenza, or the flu, is an infectious disease caused by influenza viruses. Unlike the common cold, it is characterized by a sudden onset of high fever (above 38 degrees Celsius), severe muscle pain and headache, and extreme fatigue. It typically occurs every year from late autumn to spring.
Source: 질병관리청 국가건강정보포털 · as of 2026-08-13
Treatment - Antiviral medications should be started promptly.
For influenza, there are antiviral medications (such as 'Tamiflu' containing oseltamivir), and they are most effective when started within 48 hours of symptom onset.
- If you suddenly experience high fever or severe body aches, consider visiting a hospital for an influenza test on the first or second day.
- The rapid test can be performed at the hospital and results are available in 10-15 minutes.
- In adolescents, unusual behavior has been rarely reported during the initial stages of antiviral medication use, so it is recommended that a guardian monitor them for two days after taking the medication.
Source: 질병관리청 국가건강정보포털 · as of 2026-08-13
Vaccinations - Every autumn.
The flu vaccine is updated annually to match the circulating strains, so it needs to be administered every year. The best time to get vaccinated is in October or November, before the flu season begins.
- Children (6 months to 13 years old), pregnant women, and people aged 65 or older are eligible for free vaccinations through the national program.
- It takes approximately two weeks after vaccination for immunity to develop.
Source: 질병관리청 국가건강정보포털 · as of 2026-08-13
Frequently asked questions
I have the flu, but how long do I need to rest?
Because it is highly contagious, it is recommended to refrain from going to school or work for 24 hours after the fever subsides. It is also a condition for suspension of attendance according to the School Health Law.
Is it possible to get the flu even after getting vaccinated?
It is possible. However, if you get vaccinated, even if you become infected, the symptoms are milder and the risk of complications such as pneumonia is significantly reduced. This is especially important for the elderly and children.
Sources for this page
· 질병관리청 국가건강정보포털 (as of 2026-08-13)Last checked: 2026년 8월 13일
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