Information for Schools
Questions & Answers
The Centers for Disease Control and Prevention (CDC) recognizes that school administrators, teachers, staff, and parents are concerned about the flu, particularly its effects on children. Schools are instrumental in keeping their communities healthy by taking actions such as posting information about hand hygiene in restrooms, providing flu prevention messages in daily announcements, and being vigilant about cleaning and disinfecting classroom materials.
Following are answers to questions commonly asked by school administrators, teachers, staff, and parents:
What is influenza (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 the flu is by getting a flu vaccination each year.
It is estimated that every year in the United States, on average:
- 5% to 20% of the population gets the flu;
- more than 200,000 people are hospitalized from flu complications;
- 20,000 of those hospitalized are children younger than 5 years of age; and
- a range of 3,000 to 49,000 people die from flu.
Some people, such as older people, young children, and people with certain health conditions (such as asthma, diabetes, or heart disease), are at high risk for serious flu complications.
How does the flu spread?
Most experts believe that flu viruses spread mainly by droplets made when people with flu cough, sneeze or talk. These droplets can land in the mouths or noses of people who are nearby. Less often, a person might also get flu by touching a surface or object that has flu virus on it and then touching their own mouth, eyes or possibly their nose.
What are the symptoms of the 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
Although the term “stomach flu” is sometimes used to describe vomiting, nausea, or diarrhea, these illnesses are caused by certain other viruses, bacteria, or possibly parasites, and are rarely related to influenza. Also see Cold Versus Flu.
How long is a person with flu virus contagious?
The period when an infected person is contagious depends on the age and health of the person. 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. Most healthy adults may be able to infect others beginning 1 day before symptoms develop and 5 to 7 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.
What is the difference between a cold and the flu?
The flu and the common cold are both respiratory illnesses but they are caused by different viruses. Because these two types of illnesses have similar symptoms, it can be difficult to tell the difference between them based on symptoms alone. In general, the flu is worse than the common cold, and symptoms such as fever, body aches, extreme tiredness, and dry cough are more common and intense. Colds are usually milder than the flu. People with colds are more likely to have a runny or stuffy nose. Colds generally do not result in serious health problems, such as pneumonia, bacterial infections, or hospitalizations.
How can you tell the difference between a cold and the flu?
Because colds and flu share many symptoms, it can be difficult (or even impossible) to tell the difference between them based on symptoms alone. Special tests that usually must be done within the first few days of illness can be carried out, when needed to tell if a person has the flu.
More information about Flu: The Disease.
What can I do to protect myself against the flu?
CDC recommends a yearly flu vaccine as the first and most important step in protecting against this serious disease. While there are many different flu viruses, the flu vaccine protects against the main flu viruses that research indicates will cause the most illness during the flu season. (Three or four viruses, depending on which vaccine you get.) The vaccine can protect you from getting sick from these viruses or it can make your illness milder if you get a different flu virus. See Vaccine Benefits for more information.
If you do get the flu, antiviral drugs are an important treatment option. Antiviral drugs are prescription medicines (pills, liquid or an inhaler) that fight against the flu by keeping flu viruses from reproducing in your body. Antiviral drugs can make your illness milder and make you feel better faster. They may also prevent serious flu complications. This could be especially important for people at high risk. For treatment, antiviral drugs work best if started soon after getting sick (within 2 days of symptoms). Visit Treatment - Antiviral Drugs for more information.
In addition, you should take everyday preventive actions to stop the spread of germs, like flu. This includes staying away from sick people, frequent hand washing, and cleaning and disinfecting frequently touched surfaces, especially if someone is ill, to decrease your chances of getting or spreading the flu. If you are sick with flu, reduce your contact with others and cover your cough to help keep germs from spreading. See Preventing the Flu: Good Health Habits Can Help Stop Germs for more information.
What kind of flu vaccines are there?
There are several flu vaccine options for the 2015-2016 flu season.
Traditional flu vaccines made to protect against three different flu viruses (called “trivalent” vaccines) are available. In addition, flu vaccines made to protect against four different flu viruses (called “quadrivalent” vaccines) also are available.
Trivalent flu vaccine protects against two influenza A viruses (an H1N1 and an H3N2) and an influenza B virus. The following trivalent flu vaccines are available:
- Standard-dose trivalent shots that are manufactured using virus grown in eggs. There are several different flu shots of this type available, and they are approved for people of different ages. Some are approved for use in people as young as 6 months of age. Most flu shots are given with a needle. One standard dose trivalent shot also can be given with a jet injector, for persons aged 18 through 64 years.
- A high-dose trivalent shot, approved for people 65 and older.
- A trivalent shot containing virus grown in cell culture, which is approved for people 18 and older.
- A recombinant trivalent shot that is egg-free, approved for people 18 years and older.
The quadrivalent flu vaccine protects against two influenza A viruses and two influenza B viruses. The following quadrivalent flu vaccines are available:
- A quadrivalent flu shot that is manufactured using virus grown in eggs. There are several different flu shots of this type available, and they are approved for people of different ages. Some are approved for use in people as young as 6 months of age.
- An intradermal quadrivalent shot, which is injected into the skin instead of the muscle and uses a much smaller needle than the regular flu shot. It is approved for people 18 through 64 years of age.
- A quadrivalent nasal spray vaccine, approved for people 2 through 49 years of age.
How do flu vaccines work?
Flu vaccines (the flu shot and the nasal-spray flu vaccine (LAIV)) cause antibodies to develop in the body. These antibodies provide protection against infection with the viruses that are in the vaccine. The seasonal flu vaccine protects against the main influenza viruses that research indicates will be most common during the upcoming season. About 2 weeks after vaccination, antibodies that provide protection against influenza virus infection develop in the body.
At what age should a child be vaccinated?
CDC recommends that everyone aged 6 months and older get a flu vaccine. Children younger than 6 months are too young to get vaccinated. It’s especially important that their contacts be vaccinated to protect them from possible exposure to the flu.
Children 6 months up to 9 years of age getting a flu vaccine for the first time may need two doses of vaccine the first year they are vaccinated. If possible, the first dose should be given as soon as vaccine becomes available. The second dose should be given 28 or more days after the first dose. The first dose “primes” the immune system; the second dose provides immune protection. Children who only get one dose but who need two doses can have reduced or no protection from a single dose of flu vaccine.
See Children, the Flu, and the Flu Vaccine for more information.
What kinds of flu vaccines are available for children?
- The trivalent flu vaccine protects against three flu viruses; two influenza A viruses and an influenza B virus. The following trivalent flu vaccines will be available:
- standard dose trivalent shots that are manufactured using virus grown in eggs. These are approved for people ages 6 months and older. There are different brands of this type of vaccine, and each is approved for different ages.
- The quadrivalent flu vaccine protects against four flu viruses; two influenza A viruses and two influenza B viruses. The following quadrivalent flu vaccines are:
- a standard dose quadrivalent shot. One brand is approved for people 6 months and older while others are approved for those 3 years and older.
- an intradermal dose quadrivalent shot approved for people 18 through 64 years of age.
- a standard dose quadrivalent nasal spray, approved for healthy* non-pregnant people 2 through 49 years of age when immediately available and there are no contraindications or precautions).
A complete list of influenza vaccines that are available for the 2015-2016 season can be found on CDC’s influenza website.
Your child’s health care provider will know which vaccines are right for your child.
- CDC recommends that everyone 6 months of age and older get a seasonal flu vaccine.
Keep in mind that vaccination is especially important for certain people who are high risk or who are in close contact with high risk persons. This includes children at high risk for developing complications from influenza illness, and adults who are close contacts of those children.
For the complete list of those at high risk, visit People at High Risk of Developing Flu–Related Complications.
What are influenza antiviral drugs?
Influenza antiviral drugs are prescription medicines (pills, liquid or an inhaler) that fight against the flu by keeping flu viruses from reproducing in your body. Antiviral drugs can make your illness milder and make you feel better faster. They may also prevent serious flu complications. This could be especially important for people at high risk.
How are antiviral medications used for flu?
While getting a flu vaccine each year is the best way to protect you from the flu, antiviral drugs can be used as a second line of defense to treat the flu or to prevent flu infection. For treatment, antiviral drugs work best if started soon after getting sick (within 2 days of symptoms). When used this way, these drugs can reduce the severity of flu symptoms and shorten the time you are sick by 1 or 2 days. They also may prevent serious flu complications.
Where can I get more information about the flu?
For more information and updates about the flu, call CDC’s hotline or visit CDC’s Web site. You can call the CDC Flu Information Hotline (English and Spanish) at:
- 800-CDC-INFO (800-232-4636)
- 888-232-6348 (TTY)
You can visit CDC’s flu Web site where you can access the following:
- Information about preventing the spread of flu in schools;
- “ Cover Your Cough” posters formatted for printing;
- “It’s a SNAP” toolkit, which includes activities that school administrators, teachers; and students and others can do to help stop the spread of germs in schools.
See Key Facts about Seasonal Flu, a fact sheet including information about flu symptoms, how flu spreads, and how to prevent flu.
For more information about both the flu shot and the nasal spray vaccine, visit Key Facts About Seasonal Flu Vaccine.
For more information about treating flu and flu symptoms, including information about why children or teenagers with flu-like symptoms should NOT take aspirin, visit .
- Page last reviewed: September 18, 2015
- Page last updated: May 25, 2016
- Content source:
- Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases (NCIRD)
- Page maintained by: Office of the Associate Director for Communication, Digital Media Branch, Division of Public Affairs