Flu 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 the flu? 

Anyone can get the flu, 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. 

How does the flu spread?

The flu spreads mainly from person to person by droplets from the nose or throat when an infected person coughs, sneezes or talks. Less often, 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 people 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 flu virus. 

What are flu symptoms?

Symptoms of the flu often start suddenly. People with the flu may have some or all these symptoms: 

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

Flu Complications 

Flu illness can range from mild to severe. Certain people are at an increased risk for serious complications if they get the flu –such as older people, young children, pregnant people, and 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. 

What should I do if I think I am sick with the flu? 

If you become sick with flu 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 /Tylenol) are the usual treatments. 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. 

People who are at increased risk of serious complications from the flu or people who are concerned about their illness should consult a health care provider right away to see if they should get a prescription medication (called antivirals).  

 Anyone experiencing any of the emergency warning signs listed below should seek medical evaluation as soon as possible: 

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 a health care provider do to help? 

Health care providers usually diagnose the flu based on symptoms but may perform laboratory tests. They will decide whether or not laboratory testing is necessary and recommend rest and fluids or antiviral medications. 

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 (like Tylenol or Ibuprofen) 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 the flu when you return to work or school.  

How can the flu 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. 
  • For more information on preventing the flu visit VDH’s Prevent the Flu webpage.

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Last updated August 28, 2023