| Updated Dec 10, 2003
What is the flu shot?
The flu shot is an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. It contains three influenza viruses. The three vaccine strains – 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 the flu shot are grown in eggs.
Updated Oct 7, 2004
Who should get a flu shot?
Because of a shortfall
in flu shot production for the 2004-05 flu
season, CDC is recommending that certain people
be given priority for getting the flu shot.
People in the following groups should seek
vaccination this season:
- all children aged 6–23 months;
- adults aged 65 years and older;
- persons aged 2–64 years with underlying chronic medical conditions;
- all women who will be pregnant during the influenza season;
- residents of nursing homes and long-term care facilities;
- children aged 6 months–18 years on chronic aspirin therapy;
- health-care workers involved in direct patient care; and
- out-of-home caregivers and household contacts of children aged <6 months.
These are people that are at high risk for serious flu complications or are in contact with people at high risk for serious flu complications.
Updated Oct 6, 2004
What if I am not in a priority group for vaccination
this season?
People who are not included in one
of the priority groups for vaccination this season are
asked to forego or defer vaccination because of the vaccine
supply situation.
Updated Dec 10, 2003
Who should not get a flu shot?
Talk with a doctor before getting a flu shot if you:
1) Have ever had a severe allergic reaction to eggs or to a previous flu shot
or
2) Have a history of Guillain-Barré syndrome (GBS).
If you are sick with a fever when you go to get your flu
shot, you should talk to your doctor or nurse about getting
your shot at a later date. However, you can get a flu shot
at the same time you have a respiratory illness without fever
or if you have another mild illness.
Updated Dec 10, 2003
How effective is the flu shot?
With the flu shot, when the "match" between vaccine and circulating strains
is close, the vaccine prevents influenza in about 70%-90% of healthy persons
younger than age 65 years. Among elderly persons living outside chronic-care
facilities (such as nursing homes) and those persons with long-term (chronic)
medical conditions, the flu shot is 30%-70% effective in preventing hospitalization
for pneumonia and influenza. Among elderly nursing home residents, the flu
shot is most effective in preventing severe illness, secondary complications,
and deaths related to the flu. In this population, the shot can be 50%-60%
effective in preventing hospitalization or pneumonia and 80% effective in preventing
death from the flu.
Updated Dec 10, 2003
What are the risks from getting a flu shot?
The viruses in the flu shot are killed (inactivated), so you cannot get the
flu from a flu shot. The risk of a flu shot causing serious harm, or death,
is extremely small. However, a vaccine, like any medicine, may rarely cause
serious problems, such as severe allergic reactions. Almost all people who
get influenza vaccine have no serious problems from it.
Updated Dec 10, 2003
What are the side effects that could occur?
- Soreness, redness, or swelling where the shot was given
- Fever (low grade)
- Aches
If these problems occur, they begin soon after the shot
and usually last one to two days.
Updated Dec 10, 2003
Can severe problems occur?
- Life-threatening allergic reactions are very rare. Signs
of serious allergic reaction can include breathing problems,
hoarseness or wheezing, hives, paleness, weakness, a fast
heartbeat, or dizziness. If they do occur, it is within
a few minutes to a few hours after the shot. These reactions
are more likely to occur among persons with a severe allergy
to eggs, because the viruses used in the influenza vaccine
are grown in hens' eggs. People who have had a severe reaction
to eggs or to a flu shot in the past should not get a flu
shot before seeing a physician.
- Guillain-Barré syndrome:
Normally, about one person per 100,000 people per year
will develop Guillain-Barré syndrome (GBS), an illness
characterized by fever, nerve damage, and muscle weakness.
In 1976, vaccination with the swine flu vaccine was associated
with getting GBS. Several studies have been done to evaluate
if other flu vaccines since 1976 were associated with GBS.
Only one of the studies showed an association. That study
suggested that one person out of 1 million vaccinated persons
may be at risk of GBS associated with the vaccine.
More facts about potential side effects of the influenza
vaccine can be found in "Prevention
and Control of Influenza, Recommendations of the Advisory
Committee on Immunization Practices (ACIP)."
Updated Dec 10, 2003
What should I do if I have had a serious reaction
to influenza vaccine?
- Call a doctor, or get to a doctor right away.
- Tell your doctor what happened, the date and time it
happened, and when you got the flu shot.
- Ask your doctor, nurse, or health department to file
a Vaccine
Adverse Event Reporting System (VAERS)* form, or call
VAERS at 1-800-822-7967.
*Note: This link leads outside the CDC site to another
federal agency or CDC partner site. Any links from these
sites to nonfederal organizations' links do not constitute
an endorsement of these organizations or their programs
by CDC or the federal government, and none should be inferred.
CDC is not responsible for the content of the individual
organization Web pages found at these links. The link will
open the page in a new browser window. |
