A mug of tea with lemon and honey, a blanket and citrus on a bedside table, evoking flu recovery

Influenza (Seasonal Flu)

Influenza — commonly called the flu — is a contagious respiratory illness caused by influenza viruses. Each year it circulates widely during the colder months, and while most healthy people recover within a week or two, the flu can cause serious illness, especially for certain higher-risk groups. Understanding how the flu spreads and how to prevent it can help protect you and those around you.

This article is for general education only and is not a substitute for professional medical advice. If you are very ill or at higher risk, contact a healthcare professional.

Flu or Cold?

The flu and the common cold are both respiratory illnesses, but they are caused by different viruses and tend to feel different. Colds usually come on gradually and are milder. The flu tends to come on suddenly and more intensely, often with fever, body aches and fatigue that can be severe.

Common Symptoms

  • Fever or feeling feverish and chills
  • Cough and sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches and fatigue
  • Some people, especially children, may have vomiting or diarrhea

Who Is Most at Risk?

Anyone can get the flu, but some people are more likely to develop serious complications such as pneumonia. Higher-risk groups include young children, adults aged 65 and older, pregnant people, and those with chronic conditions such as asthma, diabetes or heart disease.

Preventing the Flu

  • Annual vaccination is the best way to reduce the risk of flu and its complications, according to public-health authorities.
  • Wash your hands often with soap and water.
  • Cover coughs and sneezes and avoid touching your eyes, nose and mouth.
  • Stay home when sick to avoid spreading the virus to others.
  • Keep up healthy habits — good sleep, balanced nutrition and regular activity all support the immune system.

Recovering at Home

Most people recover with rest and fluids. Stay hydrated, rest, and treat fever and aches as directed by a healthcare provider or pharmacist. Watch for warning signs that need urgent care — such as difficulty breathing, chest pain, persistent dizziness, or symptoms that improve and then return with fever and worse cough.

Authoritative Resources

For current, detailed flu information, see the CDC's influenza resources, the MedlinePlus flu page, and the World Health Organization's seasonal influenza information.

Related reading: Diabetes and our Nutrition Basics article on supporting overall health. Return to the health article index.