Influenza, commonly known as "the flu," is a highly contagious viral infection of the respiratory tract.

    More to Know

    In the United States, flu season runs from October to May, with most cases usually occurring between late December and early March. The flu is often confused with the common cold, but the flu comes on more suddenly and is more severe.

    Symptoms can include fever, sore throat, headache, cough, weakness, and loss of appetite. After 5 days, fever and other symptoms usually disappear, but a cough and weakness may continue for up to another week. Drinking lots of fluids, getting plenty of rest, and taking acetaminophen or ibuprofen to relieve fever and aches are some simple ways to cope with the flu.

    It's important to treat the flu seriously, though, because it can lead to pneumonia, dehydration, and other life-threatening complications, particularly in infants, senior citizens, and people with long-term health problems.

    Keep in Mind

    You can protect yourself from the flu by getting vaccinated every year. The Centers for Disease Control and Prevention (CDC) recommend the flu vaccine for most people over the age of 6 months.

    All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.

Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.
© 1995-2022 KidsHealth® All rights reserved. Images provided by iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and