Flu (Influenza)
A contagious respiratory illness caused by influenza viruses.
Symptoms and what to notice
Often sudden fever or chills, cough, sore throat, runny nose, muscle aches, headache, and fatigue.
How long can it last?
Most uncomplicated cases improve in several days to under two weeks.
How serious is Flu (Influenza)?
Can cause pneumonia, worsen chronic conditions, lead to hospitalization, and cause death.
Treatment and management
Rest and fluids help mild illness. Prescription antivirals work best when started early and are especially important for higher-risk or severe cases.
Is there a vaccine—and who should receive it?
CDC recommends seasonal flu vaccination for everyone age 6 months and older, with rare exceptions. Product choice and dose count vary by age and history.
Official U.S. guidance
Read the current CDC guidance for Flu (Influenza) →
Cost: Patient cost varies by insurance, provider, location, and eligibility. Many recommended vaccines are covered with no out-of-pocket cost under qualifying plans, and eligible children may receive vaccines through the Vaccines for Children program. CDC price lists are purchasing benchmarks—not guaranteed patient prices. CDC price context.