How the Flu Spreads

The flu is highly contagious. The influenza virus spreads easily, especially during the fall and winter seasons. When an infected person coughs, sneezes, or talks, they release tiny droplets carrying the virus into the air. These droplets can enter another person's nose, mouth, or eyes, causing infection.

The virus can also survive on surfaces like doorknobs, phones, and countertops for 24 to 48 hours. If you touch a contaminated surface and then touch your face, you could get infected.

 

When Are You Most Contagious?

You are most contagious during the first three days of having symptoms. However, you can spread the virus starting from one day before symptoms begin.

Typical flu symptoms include:

  • Body aches

  • Chills

  • Cough

  • Fever (100–104°F / 37.8–40°C in adults)

  • Runny or stuffy nose

  • Sore throat

  • Upset stomach

Even after feeling better, you can still spread the flu for 5–7 days. Young children, older adults, and people with weak immune systems may stay contagious for 10 days or more.

 

What Makes People Susceptible to the Flu?

Several factors increase your risk of getting the flu:

  • Age: Young children under 5 and adults over 65 have weaker immune systems.

  • Pregnancy: Pregnant individuals are more vulnerable.

  • Chronic Conditions: Diseases like asthma, diabetes, heart disease, HIV, and severe obesity raise the risk.

  • Weakened Immune Systems: Those undergoing chemotherapy, transplant recipients, or anyone taking immunosuppressants are more susceptible.

  • Crowded Environments: Schools, offices, public transport, and healthcare facilities make it easier for the flu to spread.

 

How To Prevent Spreading and Getting the Flu

The best prevention is getting a yearly flu vaccine. Everyone aged 6 months and older should be vaccinated before flu season starts, usually peaking between December and February.

Additional prevention tips include:

  • Stay home when sick until you are fever-free for 24 hours without medication.

  • Cover your nose and mouth when coughing or sneezing.

  • Wash your hands frequently.

  • Avoid touching your face with unwashed hands.

  • Clean and disinfect commonly touched surfaces.

  • Improve indoor air quality by opening windows or using air purifiers.

  • Wear a mask if you must be around others while sick.

 

 

When To Seek Medical Care

For most healthy people, the flu resolves within a week with rest, fluids, and fever reducers like acetaminophen.

Seek medical attention if you:

  • Have a fever lasting more than three days

  • Notice worsening symptoms

  • Show signs of dehydration

  • Belong to a high-risk group
     

Healthcare providers may prescribe antivirals to shorten the illness if taken within the first 48 hours of symptoms. Common antiviral medications include:

  • Tamiflu (oseltamivir): Pill or liquid for ages 14 days and up.

  • Relenza (zanamivir): Inhaled powder for ages 7 and up (not for people with asthma).

  • Rapivab (peramivir): IV treatment for ages 6 months and older.

  • Xofluza (baloxavir marboxil): Single-dose pill for ages 5–12 (without chronic conditions) and all people over 12.
     

Go to urgent care if you or a loved one experiences:

  • Persistent high fever

  • Sevre vomiting or diarrhea

  • Intense body aches or exhaustion

  • Symptoms that improve but then worsen again

 

Emergency Signs: When to Get Help Immediately

Seek emergency care if you notice:

  • Blue or gray lips or face

  • Chest pain or pressure

  • Confusion

  • Difficulty breathing

  • Fainting

  • Fever above 104°F (40°C) in adults, or any fever in babies under 12 weeks old

  • Severe dehydration (very little or no urine)

  • Extreme dizziness or weakness

 

 

A Quick Review

The flu is a highly contagious virus that spreads through airborne droplets and contaminated surfaces. You are most contagious early in the illness but can continue spreading the virus for up to 10 days.

Young children, older adults, pregnant people, and those with compromised immune systems are at the highest risk. Protect yourself and others by getting vaccinated annually, practicing good hygiene, and staying home when sick. If you have severe symptoms or belong to a high-risk group, seek medical care quickly for antiviral treatment.