Information for Schools
Questions & Answers
The Centers for Disease Control and Prevention (CDC) recognizes that school administrators, teachers, staff, and parents are concerned about influenza (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. CDC estimates that flu-related hospitalizations since 2010 ranged from 140,000 to 710,000, while flu-related deaths are estimated to have ranged from 12,000 to 56,000.
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 and are more likely to have serious flu outcomes. The best way to prevent the flu is by getting a flu vaccination each year.
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?
CDC recommends use of injectable influenza vaccines (including inactivated influenza vaccines and recombinant influenza vaccines) during 2017-2018. The nasal spray flu vaccine (live attenuated influenza vaccine or LAIV) should not be used during 2017-2018.
Both trivalent (three-component) and quadrivalent (four-component) flu vaccines will be available.
Trivalent flu vaccines include:
- Standard-dose trivalent shots (IIV3) that are manufactured using virus grown in eggs. Different flu shots are approved for different age groups. Most flu shots are given in the arm (muscle) with a needle. One trivalent vaccine formulation 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 recombinant trivalent shot that is egg-free, approved for people 18 years and older, including pregnant women.
- A trivalent flu shot made with adjuvant (an ingredient of a vaccine that helps create a stronger immune response in the patient’s body), approved for people 65 years of age and older (new this season).
Quadrivalent flu vaccines include:
- Quadrivalent flu shots approved for use in different age groups, including children as young as 6 months.
- An intradermal quadrivalent flu 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 flu shot containing virus grown in cell culture, which is approved for people 4 years of age and older.
- A recombinant quadrivalent flu shot approved for people 18 years of age and older, including pregnant women (new this season).
How do flu vaccines work?
Flu vaccines 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.
Some children 6 months through 8 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. Your child’s doctor or other health care professional can tell you if your child needs two doses.
See Children, the Flu, and the Flu Vaccine for more information.
What kinds of flu vaccines are available for children?
Influenza vaccine options for the 2016-2017 season are listed in “TABLE. Influenza vaccines — United States, 2016–17 influenza season. Different products are approved for different age groups, including children as young as 6 months of age.
Note that while there is a quadrivalent nasal spray vaccine that is FDA approved for the U.S. market, ACIP and CDC recommend that nasal spray vaccine not be used during the 2016-2017 season because of concerns about how well it works.
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 also 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, you can 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.
- Keep Flu Out of School; Educational information and resources about flu prevention, including annual vaccination, for school nurses, parents and guardians, teachers, and students.
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 the flu shot, visit Key Facts About Seasonal Flu Vaccine.
- Page last reviewed: August 3, 2017
- Page last updated: May 15, 2018
- 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