Viral Influenza

  • The Flu: A guide for Parents  

    What is the flu?

    Influenza (the flu) is an infection of the nose, throat and lungs caused by influenza viruses that are constantly changing.  Flu causes illness, hospital stays and deaths in the United States each year.  Flu can be very dangerous for children.  Each year about 20,000 children younger than 5 years old are hospitalized from flu complications, like pneumonia.

    How serious is the flu?

    Flu illness can vary from mild to severe.  Flu can be especially dangerous for young children and children of any age who have certain long term health conditions, including asthma (even mild or controlled), neurological conditions, chronic lung disease, heart disease, blood disorders, endocrine disorders (such as diabetes), and weakened immune systems due to disease or medication.  Children with these conditions and those receiving long-term aspirin therapy, can have more severe illness from the flu. 

    How does the flu spread?

    Most experts believe that flu viruses spread mainly by 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 something that has flu virus on it and then touching their own mouth, eyes or nose. 

    What are the symptoms of flu?

    Symptoms of the flu can include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills, fatigue and sometimes vomiting and diarrhea.  Some people with flu will not have a fever.

    How long can a sick person spread the flu?

    People with the flu may infect others from 1 day before getting sick to 5-7 days after.  Children and people with weakened immune systems can shed virus for longer and might still be contagious past 7 days, especially if they still have symptoms.

    Can my child go to school, daycare or camp if he or she is sick?

    No.  Your child should stay home to rest and to avoid giving the flu to other children or to caregivers.

    When can by child go back to school after having the flu?

    Keep your child home until at least 24 hours after their fever is gone, without using fever-reducing medications, like acetaminophen (Tylenol) or ibuprofen (Motrin or Advil).  A fever is defined as 100.4o F (38o C) or higher.


    Protect your child

    How can I protect my child against flu?

    The first and most important thing to do is to get flu vaccine for your child, yourself, and everyone else in your household every year.  Get the vaccine as soon as it is available.

    Vaccination is recommended for everyone 6 months and older.

    It's especially important that young children and children with certain health conditions (see above) get vaccinated.

    It's very important for parents, grandparents, teachers and caregivers to get vaccinated.

    Everyone caring for infants under 6 months (who are too young to be vaccinated) should be vaccinated, if possible.  Vaccinating pregnant women can offer some protection to the baby during pregnancy and after birth.


    About flu vaccine  

    What kinds of flu vaccine are there?

    There are two kinds of flu vaccine:

    Inactivated (killed) flu vaccine, the "flu shot", is given by injection with a needle.

    Live, attenuated (weakened) flu vaccine is sprayed into the nostrils.

    The kind of vaccine your child will get depends on their age and health.  Your child may be eligible to receive either kind of flu vaccine.

    Every time your child receives vaccine, your healthcare provider will ask questions which will help determine whether the child should receive vaccine that day and what kind of vaccine your child should get.

    Are there any risks from flu vaccine?

    Vaccine reactions, if they occur, are usually mild and can include soreness, redness and swelling where the shot is given or runny nose after getting the nasal spray.  Some people have experienced fever, body aches, headache and fatigue.  These reactions usually begin soon after the vaccine is given and last 1-2 days.

    A vaccine, like any medicine, could possibly cause more serious problems, such as severe allergic reactions.  The risk of a vaccine causing serious harm is extremely small.  Life threatening allergic reactions from vaccines are very rare.  If they do occur, it is usually within a few minutes to a few hours after the vaccination.

    More detailed information about flu vaccine is available at  At this site you will find Vaccine Information Statements about inactivated and live influenza vaccines (the shot and the nasal spray) designed to educate and inform in many languages.

    Is influenza vaccine effective?

    Yes.  While no vaccine is 100% effective, influenza vaccine is the best protection against getting the flu.

    Influenza vaccine tends to be most effective in people who are younger and healthy.  It takes about two weeks after vaccination to protect against flu, so vaccination does not protect immediately.  Also, flu viruses are always changing, so the vaccine needs to be updated every year, before flu season starts.  When the vaccine isn't a good match with the flu viruses that are circulating, it offers less protection.

    People who get flu vaccine are much less likely to get the flu than those who don't get vaccine and, if vaccinated people get sick with the flu, their illness is not as severe.


    Other steps to take  

    What else can I do to protect my child?

    Cover coughs and sneezes with a tissue.  Throw the tissue in the trash after use.

    Stay away from people who are sick.

    Wash hands often with soap and water.

    Use an alcohol-based hand rub if soap and water are not available.

    Contact your healthcare provider if your child gets sick, especially if the child is very young (under 5) or has long-term health conditions.

    Seek emergency care if your child has trouble breathing, fast breathing, turns bluish or gray, has severe or persistent vomiting, has trouble waking up, or doesn't interact normally.

    Much more information is available at:, and

    Or call 617-983-6800 or your local board of health.