Sick with Flu? Know What to do! Comic book themed image with description of what the flu is.

What is Influenza (Flu)?

Influenza, or flu, is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs. It can cause mild to severe symptoms and life-threatening complications, including death, even in healthy children and adults.  

There are two main types of influenza (flu) viruses: types A and B. The influenza A and B viruses that routinely spread in people are responsible for seasonal flu epidemics each year. The best way to reduce the risk of flu and its potentially serious complications is by getting vaccinated each year.

When is Flu Season?

Flu seasons are unpredictable. Although widespread flu activity usually occurs every year, the timing, severity, and duration of it depend on many factors, including which flu viruses are spreading, the number of people who are susceptible to the flu viruses that are spreading, and how similar vaccine viruses are to the flu viruses that are causing illness. The timing of flu activity can vary from season to season. In the United States, seasonal flu activity most commonly peaks between December and March, but flu viruses can cause illness from early October to June.

How the Flu Spreads

Flu viruses are thought to spread primarily from person to person, mainly by tiny droplets made when people with the flu cough, sneeze or talk. These droplets can land in the mouths or noses of people who are nearby. Less often, a person might get the flu by touching a surface or object that has the flu virus on it and then touching their mouth, nose, or possibly their eyes. 

Flu Symptoms

Influenza can cause mild to severe illness, and at times can lead to death. Flu symptoms usually come on suddenly. People who have the flu often feel some or all of the following symptoms:

  • A sudden fever* (usually above 100.4°F*)
  • Feeling feverish or having chills
  • Dry, hacking cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (more tired than usual)
  • Some children may also experience vomiting and diarrhea.

*It is important to note that not everyone with the flu will have a fever.

Is it a Cold or Flu? Symptom Comparison Graphic

Onset of Symptoms

The time from when a person is exposed and infected with the flu to when symptoms begin is about two days but can range from approximately 1-4 days.


Period of Contagiousness

You may be able to spread the flu to someone else before you know you are sick, as well as when you are sick with symptoms.

  • People with the flu are most contagious in the first 3-4 days after their illness begins.
  • Some otherwise healthy adults may be able to infect others beginning one day before symptoms develop and up to five to seven days after becoming sick.
  • Some people, especially young children and people with weakened immune systems, might be able to infect others for an even longer time.



Complications of the Flu

Most people who get the flu will recover in a few days to less than two weeks, but some people will develop complications (such as pneumonia) as a result of the flu, some of which can be life-threatening and result in death. Complications can include:

  • Sinus and ear infections
  • Pneumonia
  • Inflammation of the heart (myocarditis), brain (encephalitis), muscle tissues (myositis, rhabdomyolysis), and multi-organ failure (i.e. respiratory failure, kidney failure, etc.)
  • Flu virus infection of the respiratory tract can trigger an extreme inflammatory response in the body and can lead to sepsis
  • Influenza can make chronic medical problems worse (i.e. asthma, chronic heart disease, etc.)


People at Higher Risk

Anyone can get sick with the flu, even healthy people, and serious problems related to the flu can happen to anyone at any age, but some people are at higher risk of developing serious flu-related complications if they get sick. This includes:

  • People aged 65 years or older
  • People of any age with certain chronic medical conditions (such as asthma, diabetes, or heart disease)
  • Pregnant mothers
  • Children younger than 5 years, but especially those younger than 2 years old.

Help Them Fight Flu so They Can Do What They Do graphic with picture of kid playing soccer.


Caring for Your Child's Cold or Flu

Unfortunately, there is no cure for the common cold. Antibiotics may be used to fight bacterial infections, but they have no effect on the influenza virus. The best you can do is to make your child comfortable:

The most important way to care for your child is to ensure your child gets plenty of rest and drinks enough fluids!
Symptom: Stuffy Nose
  • Salt water (saline) nose spray/drops may be used
  • Use a cool-mist humidifier (also called a vaporizer) in your child's room. Put it close to your child while also keeping it safely out of their reach. Make sure you clean and dry the humidifier each day to stop bacteria or mold from growing, which would result in making your child even sicker. Hot water vaporizers should not be used - the hot water or steam can burn your child.
Symptom: Cough
  • Honey may be used for children over the age of 1.Do not give honey to babies under 1 year as it is a choking hazard! If honey is given at bedtime, make sure your child's teeth are brushed afterward!
    • For children ages 1-5, try 1/2 teaspoon of honey
    • For children ages 6-11, try 1 teaspoon of honey
    • For children 12 or older, try 2 teaspoons of honey
  • Cough drops or lozenges may be used for children ages 4 and older. Do not use with children under the age of 4, as they present a choking hazard
  • If your child is coughing in their sleep, mentholated rubs (like Vick's Vapor Rub) may be used for children ages 2 years and older. Rub a thick layer on top of the skin on the chest and the front of the neck (throat area). The body's warmth helps the medication go into the air slowly over time. The child breathes in this air, which helps to soothe a cough, so the child can sleep. Keep mentholated rub away from children at all times!
Symptom: Fever
  • Ibuprofen or Acetaminophen may be used to relieve symptoms. NEVER give a child aspirin! Always call your pediatrician before giving medicine to a child under 2 years of age and call immediately if your child is under three months of age and has a fever. 

Take Antiviral Drugs if Your Doctor Prescribes Them! graphic

Is There Medicine to Treat Influenza?

For most people, the flu will clear up on its own, but there are antiviral drugs that can be prescribed by your doctor to treat flu illness. These prescription drugs can shorten your illness and make it milder while also preventing serious complications that could result in hospitalization. Antiviral treatment of the flu works best when given as soon as possible, ideally 1-2 days after symptoms develop. Antivirals can be given to most children and pregnant women.

The CDC recommends that antiviral drugs be used early to treat people who are very sick with the flu and people who get flu symptoms and who are at high risk of serious flu complications, either because of their age or because they have a high-risk medical condition.


Preventative Actions

  • Take time to get a flu vaccine. The CDC recommends an annual flu vaccine as the first and most important step in protecting against flu viruses. Flu vaccines help to reduce the burden of flu illnesses, hospitalizations, and deaths on the healthcare system each year. Vaccines are especially important for people in high-risk groups (see above).
  • Avoid close contact with people who are sick. If your child is sick, limit contact with others as much as possible to keep from infecting them.
  • Teach your child/children to cover their coughs and sneezes by covering their nose and mouth with a tissue and disposing of the tissue when done. 
  • Wash hands often with soap and water. If soap and water are not available, use an alcohol-based hand rub.
  • Clean and disinfect surfaces and objects that may be contaminated with viruses that cause the flu.
Picture of 3 arms with Band-Aids on them. "Get yourself and your family VACCINATED! A yearly flu vaccine is the first and most important step in protecting against flu viruses


Influenza Vaccine Information for 2022-23

It is recommended that everyone 6 months and older in the United States should get the influenza (flu) vaccine every season. An annual seasonal flu vaccine is the best way to help reduce the risk of getting the flu and any of its potentially serious complications.

Vaccination has been shown to have many benefits, including reducing the risk of flu illnesses, hospitalizations, and even the risk of flu-related death. While some people who get a flu vaccine may still get sick with influenza, flu vaccination has been shown in several studies to reduce the severity of illness.

How do Flu Vaccines Work? Flu vaccines cause antibodies to develop in the body about two weeks after vaccination. These antibodies protect against flu illness. Seasonal flu vaccines are designed to protect against the influenza viruses that research indicates will be most common during the upcoming season. All flu vaccines in the United States protect against four different flu viruses: an influenza A(H1N1) virus, an influenza A(H3N2) virus, and two influenza B viruses.

Do Flu Vaccines Work Right Away? No. It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against influenza virus infection. That’s why it’s best to get vaccinated before influenza viruses start to spread in your community.

Vaccine Effectiveness. Influenza (flu) vaccine effectiveness (VE) can vary. The protection provided by a flu vaccine varies from season to season and depends in part on the age and health status of the person getting the vaccine and the similarity or “match” between the viruses in the vaccine and those in circulation.

During years when the flu vaccine match is good, it is possible to measure substantial benefits from flu vaccination in terms of preventing flu illness and complications. However, the benefits of flu vaccination will still vary, depending on the characteristics of the person being vaccinated (for example, their health and age), what flu viruses are circulating that season, and, potentially, which type of flu vaccine was used. More information is available at Vaccine Effectiveness – How well does the Flu Vaccine Work?

Flu Vaccine Options. For people younger than 65 years, CDC does not preferentially recommend any licensed, age-appropriate influenza (flu) vaccine over another during the 2022-2023 flu season. Options for this age group include inactivated influenza vaccine [IIV], recombinant influenza vaccine [RIV], or live attenuated influenza vaccine (LAIV), with no preference for any flu vaccine over another. 

New for this season: For people 65 years and older, three flu vaccines are preferentially recommended over standard-dose, unadjuvanted flu vaccines. These are the Fluzone High-Dose Quadrivalent vaccineFlublok Quadrivalent recombinant flu vaccine , and Fluad Quadrivalent adjuvanted flu vaccine. More information is available at Flu & People 65 Years and Older.

Flu Vaccine Types Table (image)

Available flu vaccines include:

  • Standard-dose flu shots that are manufactured using the virus grown in eggs. These vaccines are approved for use in children as young as 6 months. Most flu shots are given in the arm (muscle) with a needle.
  • cell-based flu shot containing virus grown in cell culture, which is approved for people 6 months and older. This vaccine is completely egg-free.
  • recombinant flu shot, which is a completely egg-free flu shot that is approved for use in people 18 years and older. This shot is made without flu viruses and contains three times the antigen (the part of the vaccine that helps your body build up protection against flu viruses) than other standard-dose inactivated flu vaccines, to help create a stronger immune response.
  • An egg-based high-dose, which is approved for use in people 65 years and older. This vaccine contains four times the antigen (the part of the vaccine that helps your body build up protection against flu viruses) than other standard-dose inactivated flu vaccines, to help create a stronger immune response.
  • An egg-based adjuvanted flu shot, which is approved for people 65 years and older. This vaccine is made with an adjuvant (an ingredient that helps create a stronger immune response).
  • An egg-based live attenuated flu nasal spray vaccine made with weakened live flu viruses, which is approved for use in people 2 years through 49 years. This vaccine is not recommended for use in pregnant people, immunocompromised people, or people with certain medical conditions.

Other Helpful Influenza Resources
FluView: A Weekly Influenza Surveillance REport Prepared by the Influenza Division of the CDC
Keep your family strong. Vaccinate. Fight Flu.