Influenza Basics

What is influenza (also called “the flu”)?
Influenza is commonly referred to as “the flu.” It is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs. There are two main types of influenza virus: A and B. Each type includes many different strains that tend to change from year to year.

Who gets influenza?
Anyone can get influenza, but it is most serious in young children, older persons, in people with chronic illnesses (e.g., lung disease, heart disease, cancer, or diabetes) or those with weakened immune systems.

Influenza Symptoms
Symptoms of flu can include a sudden onset of:

  • Fever* or feeling feverish/ having chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (feeling very tired)
  • Some children may have vomiting and diarrhea

Influenza Complications
Flu illness can range from mild to severe. Certain people are at greater risk for serious complications if they get the flu – older people, young children, pregnant women, those with chronic illnesses.

Complications of flu can include bacterial pneumonia, ear infections, sinus infections, dehydration, and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes.
Although most people are ill for less than a week, serious complications can lead to hospitalization and even death.

How Influenza Spreads
Influenza spreads mainly from person to person by droplets from the nose or throat that are released when an infected person coughs, sneezes or talks. Sometimes, people may become infected by touching something with influenza virus on it and then touching their mouth, nose or possibly their eyes before washing their hands.

Most healthy adults may be able to infect others beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick. This can be longer in some people, especially children and people with weakened immune systems. This means that you may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick. Symptoms usually appear 1 to 4 days after exposure to the influenza virus.

What should I do if I think I am sick with influenza?
If you become ill with influenza symptoms, you should stay home and avoid contact with other people except to seek medical care. Most people are able to recover at home without medical care.

Rest, liquids, and over-the-counter medicine for fever (e.g., acetaminophen) are the usual treatments. Some prescription drugs may reduce the severity of influenza. Aspirin should not be given to children with fever-causing illnesses because of the possibility of a complication called Reye’s syndrome. Antibiotics are not effective at fighting the flu.

Although some people are at greater risk of serious flu-related complications, it is also possible for otherwise healthy people to develop severe illness. People who are concerned about their illness should consult their doctor for advice. Experiencing any of the emergency warning signs listed below means that you or your child should seek medical evaluation without delay.

Emergency Warning Signs In Children:

  • Fast breathing or trouble breathing
  • Bluish skin color
  • Not drinking enough fluids
  • Not waking up or not interacting
  • Being so irritable that the child does not want to be held
  • Flu-like symptoms improve but then return with fever and worse cough
  • Fever with a rash

Emergency Warning Signs In Adults:

  • Difficulty breathing or shortness of breath
  • Pain or pressure in the chest or abdomen
  • Sudden dizziness
  • Confusion
  • Severe or persistent vomiting

What can the doctor do to help?
Doctors usually diagnose influenza based on symptoms but may perform laboratory tests. The doctor will decide whether or not laboratory testing is necessary. The doctor may recommend rest and fluids, or start antiviral medications (pills, liquid, or an inhaled powder).

How long should I stay home if I’m sick?
The Centers for Disease Control and Prevention (CDC) recommends that you stay home for at least 24 hours after your fever is gone without the use of fever-reducing medicine except to get medical care or for other necessities. Stay away from others as much as possible to keep from making others sick. Continue to cover coughs and sneezes and wash hands even after fully recovering from flu when you return to work or school. It is important to know that even if you don’t have a fever, you may have flu and be contagious if you get flu-like symptoms.

How can influenza be prevented?

  • Everyone who is at least 6 months of age should get vaccinated.
  • Stop the spread of flu and other germs by covering your mouth and nose with a tissue when coughing or sneezing. Promptly throw away tissues after they are used. Wash your hands often to help protect yourself from germs, and avoiding touching your eyes, nose, or mouth.
  • Stay home from work, school, and other activities when you are sick, and avoid close contact with people who are sick.

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