Influenza, also known as the flu, is a contagious disease that is caused by the influenza virus. It attacks the respiratory tract in humans (nose, throat, and lungs). The flu is different from a cold. Influenza usually comes on suddenly and may include these symptoms:
These symptoms are usually referred to as "flu-like symptoms."
The Flu Season
In the Northern hemisphere, winter is the time for flu. In the United States, the flu season can range from November through March, and even past March in some years. During the past 21 flu seasons, months with the heaviest flu activity (peak months) occurred in December in 4 years, January in 5 years, February in 9 years, and March in 3 years.
Anyone Can Get the Flu, But the Disease Is More Severe for Some People
Most people who get influenza will recover in one to two weeks, but some people will develop life-threatening complications (such as pneumonia) as a result of the flu. Millions of people in the United States — about 5% to 20% of U.S. residents — will get influenza each year. An average of about 36,000 people per year in the United States die from influenza, and 114,000 per year have to be admitted to the hospital as a result of influenza. Anyone can get the flu (even healthy people), and serious problems from influenza can happen at any age. People age 65 years and older, people of any age with chronic medical conditions, and very young children are more likely to get complications from influenza. Pneumonia, bronchitis, and sinus and ear infections are three examples of complications from flu. The flu can make chronic health problems worse. For example, people with asthma may experience asthma attacks while they have the flu, and people with chronic congestive heart failure may have worsening of this condition that is triggered by the flu.
Vaccinations and Medications
According to the Centers for Disease Control, the single best way to prevent the flu is to get vaccinated each fall . In the absence of vaccine, however, there are other ways to protect against flu.
Antiviral Medications can also be used to prevent the flu .
Who Should Be Vaccinated
People who should be vaccinated include:
Vaccine Information for Other Groups
The risk of getting influenza during travel depends on the destination and time of travel. In the tropics, influenza can occur year-round. In the Southern Hemisphere, most influenza activity occurs April through September. Travelers also can be exposed during the summer, especially when traveling in tourist groups that include people from parts of the world where influenza virus is circulating.
Depending on the health condition of prospective travelers, providers should consider vaccinating people at high risk for influenza-related complications, especially if they plan to:
Also, providers may want to consider prescribing antiviral medications for prevention or treatment to people 50 years and older at high risk for influenza complications who cannot be vaccinated.
Who Should Not Be Vaccinated
The following people should not be vaccinated:
Prophylactic use of antiviral agents is an option for preventing influenza among such people.
The full Recommendations of the Advisory Committee on Immunization Practices (ACIP) on the Prevention and Control of Influenza can be found at www.cdc.gov/mmwr/preview/mmwrhtml/rr5306a1.htm.
For more information, visit www.cdc.gov/flu or call the National Immunization hotline at (800)232-2522 (English), (800)232-0233 (Spanish), or the CDC clinician hotline at 877-554-4625.
Other Good Health Habits
Avoid close contact
Avoid close contact with people who are sick. When you are sick, keep your distance from others to protect them from getting sick too.
Stay home when you are sick
If possible, stay home from work, school, and errands when you are sick. You will help prevent others from catching your illness.
Cover your mouth and nose
Cover your mouth and nose with a tissue when coughing or sneezing. It may prevent those around you from getting sick.
Clean your hands
Washing your hands often will help protect you from germs.
Avoid touching your eyes, nose or mouth
Germs are often spread when a person touches something that is contaminated with germs and then touches his or her eyes, nose, or mouth.