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.
The following are some answers to questions commonly asked by school administrators, teachers, staff, and parents:
General Information about the Disease
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.
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?
Flu viruses spread mainly from person to person through coughing or sneezing of people with influenza. Sometimes people may become infected by touching something with flu viruses on it and then touching their mouth or nose. Most healthy adults may be able to infect others beginning 1 day before symptoms develop and up to 5 days after becoming sick. That 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.
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. Studies show that most healthy adults may be able to infect others from 1 day prior to becoming sick and for 5 days after they first develop symptoms. Some young children with weakened immune systems may be contagious for longer than a week.
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 flu-like 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.
Preventing and Treating the Flu
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 three main flu strains that research indicates will cause the most illness during the flu season. The vaccine can protect you from getting sick from these three viruses or it can make your illness milder if you get a different flu virus.
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).
In addition, you can take like 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 the flu. If you are sick with flu, reduce your contact with others and cover your cough to help keep germs from spreading.
What kind of flu vaccines are there?
There are two types of vaccines that protect against the flu. The “flu shot” is an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. The flu shot is approved for use among people 6 months of age or older, including healthy people and those with chronic medical conditions (such as asthma, diabetes, or heart disease). A different kind of vaccine, called the nasal-spray flu vaccine (sometimes referred to as LAIV for Live Attenuated Influenza Vaccine or FluMist®), was approved in 2003. The nasal-spray flu vaccine contains attenuated (weakened) live viruses, and is administered by nasal sprayer. It is approved for use only among healthy* people 2-49 years of age who are not pregnant.
Each of the two types of vaccine contains three influenza viruses, which are chosen based on information about recently circulating strains. Each of the three vaccine strains in both vaccines – one A (H3N2) virus, one A (H1N1) virus, and one B virus – are representative of the influenza vaccine strains recommended for that year. Viruses for both vaccines are grown in eggs.
* “Healthy” indicates persons who do not have an underlying medical condition that predisposes them to influenza complications.
How do flu vaccines work?
The seasonal flu vaccine protects against three influenza viruses that research indicates will be most common during the upcoming season. This season's flu vaccine provides protection against the three main viruses that research indicates will cause the most illness this season -- an influenza A (H1N1) virus, an influenza A (H3N2) virus and an influenza B virus. About 2 weeks after vaccination, antibodies that provide protection against influenza virus infection develop in the body.
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.
At what age should a child be vaccinated?
CDC recommends that all children aged 6 months up to their 19th birthday get a flu vaccine. CDC also recommends that people in contact with certain groups of children get a flu vaccine in order to protect the child (or children) in their lives from the flu.
The following contacts of children are recommended for influenza vaccination by CDC:
- Close contacts of children younger than 5 years old (people who live with them) should get a flu vaccine.
- Out-of-home caregivers (nannies, daycare providers, etc.) of children younger than 5 years old should get a flu vaccine.
- People who live with or have other close contact with a child or children of any age with a chronic health problem (asthma, diabetes, etc.) should get a flu vaccine.
- In addition, CDC recommends that all health care workers be vaccinated each year to keep from spreading the flu to their patients.
Children 6 months up to 9 years of age getting a flu vaccine for the first time will need two doses of vaccine the first year they are vaccinated. If possible, the first dose should be given in September or 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. Two doses are necessary to protect these children.
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 make you less contagious to other people.
Flu Resources for Schools
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:
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.
See The Flu: A Guide for Parents [252 KB, 2 pages] , a flyer answering questions about the flu, how to protect your child, treatment, and more.
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 Other Important Information For People Sick With Flu.