What is the flu?

The flu (influenza) is a contagious respiratory disease caused by flu viruses. It is spread from person to person by coughing or sneezing. It can also be spread by touching contaminated surfaces.

Symptoms of flu include fever or feeling feverish/chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headache, and tiredness. Nausea, vomiting, and diarrhea also can occur but are more common in children than adults. Young children, senior citizens, and people who have chronic health conditions are at risk for serious complications. These complications can include pneumonia, ear infections, sinus infections, dehydration, worsening of chronic medical conditions, and death.

Who is at risk?

Flu is common throughout the world. The flu season lasts from October through May in the Northern Hemisphere and from April through September in the Southern Hemisphere. In tropical countries, flu can be spread year-round.

Travel to tropical countries or countries in the Southern Hemisphere can put you at risk for the flu outside the regular fall/winter flu season in the United States.

What can travelers do to prevent the flu?

Get a flu vaccine

  • The Centers for Disease Control (CDC) recommends a yearly flu vaccine as the first and most important step in protecting against flu viruses.
  • A flu vaccine protects against the three viruses that research suggests will be most common.
  • Everyone 6 months of age and older should get a flu vaccine as soon as the current season’s vaccines are available.
  • Vaccinating people at high risk decreases their risk of severe flu illness. People at high risk for developing flu-related complications include:
    • Children younger than 5 years old
    • Adults 65 years of age and older
    • Pregnant women
    • People who have medical conditions such as asthma, lung disease or heart disease

Stop the spread of germs

  • Try to avoid close contact with sick people.
  • If you get sick with flu-like illness, the CDC recommends that you stay home for at least 24 hours after the fever is gone except to get medical care or for other necessities. The fever should be gone without the use of a fever-reducing medicine.
  • While sick, limit contact with others as much as possible to keep from infecting them.
  • Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
  • Wash your hands often with soap and water. If soap and water are not available, use an alcohol-based hand sanitizer.
  • Avoid touching your eyes, nose, and mouth. Germs spread this way.
  • Clean and disinfect surfaces and objects that may be contaminated with germs like the flu.

Page reviewed on: Mar 09, 2017

Page reviewed by: Jessie L. Leyse, MD