What is influenza?
Influenza is commonly referred to as “the flu.” It is a contagious respiratory illness caused by influenza viruses. Flu can cause mild to severe illness, and at times can lead to death. There are two main types of flu viruses that cause ilness: Types A and B. Type A has many different subtypes based on proteins on the surface of the virus that tend to change from year to year. Type B has two lineages and generally changes more slowly compared to type A influenza viruses. Flu viruses can be detected year-round in the United States, but they are most common during the fall and winter.
Who gets flu?
Anyone can get flu and develop serious illness, but some people are at increased risk of developing serious flu-related complications. This includes young children (under the age of 5 years, but especially those younger than 2 years, pregnant women, people aged 65 years and older, and people with chronic illnesses (e.g., lung disease, heart disease, cancer, or diabetes) or weakened immune systems.
How is flu spread?
Flu spreads mainly by tiny droplets from the nose or mouth that are released when a person with flu coughs, sneezes or talks. These droplets can land in the mouths or noses of people who are nearby. Less often, a person might get flu by touching a surface or object that has the flu virus on it and then touching his or her mouth, nose, or eyes. People with flu are most contagious in the first 3 to 4 days after their illness begins. Some people can start spreading the virus beginning one day before symptoms develop and up to five to seven days after becoming sick. Young children and some people with weakened immune systems, might be able to infect others for an even longer time.
What are the symptoms of flu?
Flu symptoms can include a sudden onset of fever or feeling feverish/chills, cough, sore throat, runny or stuffy nose, headache, fatigue, and muscle or body aches. Some people may have vomiting and diarrhea, but this is more common in children. Most people with flu recover within a few days to less than two weeks. However, some people might develop severe or life-threatening complications, like pneumonia.
How soon after exposure do symptoms appear?
The time from when a person is exposed and infected with flu to when symptoms begin is about 2 days but can range from about 1 to 4 days.
How is flu diagnosed?
Doctors usually diagnose flu based on symptoms, but it is very difficult to distinguish flu from other viral or bacterial respiratory illnesses based on symptoms alone. Many doctors might not test for flu because the test results usually do not change how you are treated. However, when appropriate your doctor might use laboratory tests to identify the virus.
What is the treatment for flu?
Rest, liquids, and over-the-counter medicines for fever and discomfort are the usual treatments. Prescription antiviral drugs are available for people who are at increased risk of developing serious flu complications and can reduce the severity of flu when started within 1to 2 days after symptoms begin. Aspirin should not be given to children younger than 19 years old with fever-causing illnesses because of the possibility of a rare but serious illness called Reye’s syndrome. Antibiotics are not used to treat flu.
How can flu be prevented?
You can take the following measures to help protect yourself and others from the flu:
- Getting a flu vaccine every year is the most important action you can take to prevent the flu.
- Take everyday preventative actions like
- Cover your mouth and nose with a tissue or your elbow when coughing or sneezing.
- 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 or mouth.
- Stay home from work, school, and other activities when you are sick. Do not return until you’ve had no fever for at least 24 hours without the use of a fever-reducing medicine.
- Avoid close contact with people who are sick. If you are sick, limit contact with others as much as possible.
- Clean frequently touched surfaces and objects that might be contaminated with flu viruses.
- Take flu antiviral drugs if your doctor prescribes them.
Who should be vaccinated against flu?
Everyone aged six months or older, with rare exceptions, should get a flu vaccine each year. Vaccination is particularly important for people who are at increased risk of developing serious flu complications. People at increased risk include but are not limited to:
- Adults aged 65 years or older
- Children younger than 5 years old
- Pregnant people and people up to 2 weeks after the end of pregnancy
- People with asthma, chronic lung disease, diabetes, or other chronic medical conditions and
- Immunocompromised people
If I was vaccinated for flu last year, do I need to get vaccinated this year?
Yes. It is important to get vaccinated for flu every year. The flu vaccine formulation changes year to year to best match the flu viruses research indicates will be most common during the upcoming season. Also, protection from the flu vaccine decreases over time, so getting a flu vaccine every year will give you the best protection.
How can I get more information about flu?
- If you have concerns about flu, contact your healthcare provider.
- Call your local health department. A directory of local health departments is located at www.vdh.virginia.gov/local-health-districts.
- Visit the Virginia Department of Health website at www.vdh.virginia.gov/epidemiology/influenza-flu-in-virginia/ or the Centers for Disease Control and Prevention website at hwww.cdc.gov/flu.