What is Influenza (also called flu)?
The flu is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness and at times can lead to death. The best way to prevent this illness is by getting a flu vaccination each fall.
Every year in the United States, on average:
- 5 to 20 percent of the population gets the flu,
- more than 200,000 people are hospitalized from flu complications and
- about 36,000 people die from flu.
Some people, such as older people, young children and people with certain health conditions, are at high risk for serious flu complications.
Symptoms of Flu
Symptoms of flu include:
- fever (usually high)
- extreme tiredness
- dry cough
- sore throat
- runny or stuffy nose
- muscle aches
- stomach symptoms, such as nausea, vomiting and diarrhea, also can occur but are more common in children than adults
Complications of Flu
Complications of flu can include bacterial pneumonia, dehydration and worsening of chronic medical conditions, such as congestive heart failure, asthma or diabetes. Children may get sinus problems and ear infections.
How Flu Spreads
Flu viruses spread in respiratory droplets caused by coughing and sneezing. They usually spread from person to person, though sometimes people become infected by touching something with flu viruses on it and then touching their mouth or nose. Most healthy adults may be able to infect others beginning one day before symptoms develop and up to five days after becoming sick. That means that you can pass on the flu to someone else before you know you are sick, as well as while you are sick.
Preventing the Flu: Get Vaccinated
The single best way to prevent the flu is to get a flu vaccination each fall. There are two types of vaccines:
- The “flu shot” — an inactivated vaccine (containing killed virus) that is given with a needle. The flu shot is approved for use in people older than 6 months, including healthy people and people with chronic medical conditions.
- The nasal-spray flu vaccine — a vaccine made with live, weakened flu viruses that do not cause the flu (sometimes called LAIV for â€œLive Attenuated Influenza Vaccineâ€). LAIV is approved for use in healthy people 5 years to 49 years of age who are not pregnant.
About two weeks after vaccination, antibodies develop that protect against influenza virus infection. Flu vaccines will not protect against influenza-like illnesses caused by other viruses.
When to Get Vaccinated
October or November is the best time to get vaccinated, but getting vaccinated in December or even later can still be beneficial. Flu season can begin as early as October and last as late as May.
Who Should Get Vaccinated?
In general, anyone who wants to reduce their chances of getting the flu can get vaccinated. However, certain people should get vaccinated each year. They are either people who are at high risk of having serious flu complications or people who live with or care for those at high risk for serious complications.
People who should get vaccinated each year are:
- People at high risk for complications from the flu:
- People 65 years and older;
- People who live in nursing homes and other long-term care facilities that house those with long-term illnesses;
- Adults and children 6 months and older with chronic heart or lung conditions, including asthma;
- Adults and children 6 months and older who needed regular medical care or were in a hospital during the previous year because of a metabolic disease (like diabetes), chronic kidney disease or weakened immune system (including immune system problems caused by medicines or by infection with human immunodeficiency virus [HIV/AIDS]);
- Children 6 months to 18 years of age who are on long-term aspirin therapy. (Children given aspirin while they have influenza are at risk of Reye syndrome.);
- Women who will be pregnant during the influenza season;
- All children 6 to 23 months of age;
- People with any condition that can compromise respiratory function or the handling of respiratory secretions (that is, a condition that makes it hard to breathe or swallow, such as brain injury or disease, spinal cord injuries, seizure disorders or other nerve or muscle disorders.)
- People 50 to 64 years of age. Because nearly one-third of people 50 to 64 years of age in the United States have one or more medical conditions that place them at increased risk for serious flu complications, vaccination is recommended for all persons aged 50 to 64.
- People who can transmit flu to others at high risk for complications. Any person in close contact with someone in a high-risk group (see above) should get vaccinated. This includes all health care workers, household contacts and out-of-home caregivers of children 6 to 23 months of age and close contacts of people 65 years and older.
Use of the Nasal Spray Flu Vaccine
It should be noted that vaccination with the nasal-spray flu vaccine is always an option for healthy persons aged 5 to 49 years who are not pregnant. This vaccine is not subject to prioritization and can be given to healthy 5- to 49-year-olds at any time.
Who Should Not Be Vaccinated
Some people should not be vaccinated without first consulting a physician. They include:
- People who have a severe allergy to chicken eggs.
- People who have had a severe reaction to an influenza vaccination in the past.
- People who developed Guillain-BarrÃ© syndrome (GBS) within six weeks of getting an influenza vaccine previously.
- Children less than 6 months of age (influenza vaccine is not approved for use in this age group).
- People who have a moderate or severe illness with a fever should wait to get vaccinated until their symptoms lessen.
If you have questions about whether you should get a flu vaccine, consult your health care provider.
Revised July 2013