Flu – When to Worry and When to See a Doctor

5 facts about the flu

1. The flu is caused by a virus (not bacteria).
   Antibiotics don’t work against the flu unless there’s a secondary bacterial infection.

2. It spreads very easily.
   Flu viruses spread through coughs, sneezes, talking, and touching contaminated surfaces, then touching your eyes, nose, or mouth.

3. Symptoms usually start suddenly.
   Unlike a cold, flu symptoms often come on fast and include fever, chills, body aches, fatigue, headache, sore throat, and cough.

4. You’re most contagious early on.
   People can spread the flu 1 day before symptoms start and up to 5–7 days after becoming sick (longer in children or those with weak immune systems).

5. The flu vaccine lowers risk and severity.
   Even if it doesn’t fully prevent infection, vaccination greatly reduces the chance of severe illness, hospitalization, and complications.

When to worry

You should be more concerned if any of the following happen:

• Fever lasts more than 3–4 days

• Symptoms improve, then suddenly get worse

• Severe or persistent vomiting

• Signs of dehydration (very little urine, dry mouth, dizziness)

• Chest pain or worsening cough

• Extreme fatigue or confusion

When to see a doctor right away

For adults:

• Difficulty breathing or shortness of breath

• Chest pain or pressure

• Confusion or trouble staying awake

• Bluish lips or face

• High fever that doesn’t come down with medication

For children:

• Fast or labored breathing

• Not drinking fluids or no tears when crying

• Fever with a rash

• Not waking up or not interacting

• Seizures

People who should see a doctor earlier, even with mild symptoms:

• Adults 65 and older

• Children under 5 years (especially under 2)

• Pregnant people