Key Facts about 2009 H1N1 Flu Vaccine
November 9, 2009

A flu vaccine is the single best way to protect against influenza illness. This season, there is a seasonal flu vaccine to protect against seasonal flu viruses and a 2009 H1N1 vaccine to protect against the 2009 H1N1 influenza virus (sometimes called “swine flu”). This page contains information about the 2009 H1N1 flu vaccine and is adapted from CDC materials published November 3, 2009.

What kinds of vaccines are there?  There are two kinds of 2009 H1N1 vaccines being produced:

• A 2009 H1N1 "flu shot" — an inactivated vaccine (containing killed virus) that is given as a shot, usually in the arm. The indications for who can get the 2009 H1N1 flu shot are the same as for seasonal flu shots. The flu shot is approved for use in people 6 months of age and older, including healthy people, people with chronic medical conditions and pregnant women. 
• The 2009 H1N1 nasal spray flu vaccine — a vaccine made with live, weakened viruses that do not cause the flu (sometimes called LAIV for "live attenuated influenza vaccine"). The indications for who can get the 2009 H1N1 nasal spray vaccine are the same as for seasonal nasal spray vaccine. LAIV is approved for use in healthy* people 2 years to 49 years of age who are not pregnant.

About 2 weeks after vaccination, antibodies that provide protection against 2009 H1N1 influenza virus infection will develop in the body.  The 2009 H1N1 vaccine will not protect against seasonal influenza viruses.

When to Get Vaccinated?  As soon as possible! 

Who Should Get Vaccinated?
CDC’s Advisory Committee on Immunization Practices (ACIP), a panel made up of medical and public health experts, met July 29, 2009, to make recommendations on who should receive the 2009 H1N1 vaccine when it becomes available. While the federal government has purchased enough vaccine so that anyone who wants to get vaccinated can, ACIP’s statement on the “Use of Influenza A (H1N1) 2009 Monovalent Vaccine” recommends that vaccination efforts should focus first on people in five target groups:  

•  Pregnant women
• Persons who live with or provide care for infants age 6 months or younger (examples: parents, siblings, daycare providers)
• Health care and emergency medical services personnel who have direct contact with patients or infectious material
• Children age 6 months - 4 years
• Children and adolescents age 5-18 years who have chronic medical conditions that put them at higher risk for influenza-related complications

Who Should Not Be Vaccinated?
There are some people who should not get any flu vaccine without first consulting a physician. These include:

• People who have a severe allergy to chicken eggs.
• People who have had a severe reaction to an influenza vaccination.
• People who developed Guillain-Barré syndrome (GBS) within 6 weeks of getting an influenza vaccine previously. For more information, go to:   http://www.cdc.gov/h1n1flu/vaccination/vaccine_safety.htm
• Children younger than 6 months of age (influenza vaccine is not approved for this age group), and
• People who have a moderate-to-severe illness with a fever (they should wait until they recover to get vaccinated.)

Vaccine Effectiveness
The ability of a flu vaccine to protect a person depends on the age and health status of the person getting the vaccine, and the similarity or "match" between the viruses or virus in the vaccine and those in circulation. For more information about flu vaccine effectiveness, go to: http://www.cdc.gov/h1n1flu/vaccination/vaccine_safety.htm  

Vaccine Side Effects (What to Expect)
The same side effects typically associated with the seasonal flu shot and the seasonal nasal spray vaccine are expected with the 2009 H1N1 flu shot and 2009 H1N1 nasal spray vaccine.

For the flu shot: The viruses in the flu shot are killed (inactivated), so you cannot get the flu from a flu shot. Some minor side effects that could occur are soreness, redness, or swelling where the shot was given, fever (low grade), aches

The nasal spray: The viruses in the nasal-spray vaccine are weakened and do not cause severe symptoms often associated with influenza illness. (In clinical studies, transmission of vaccine viruses to close contacts has occurred only rarely.)  In adults, side effects from LAIV can include runny nose, headache, sore throat, or cough.