Key facts about seasonal flu vaccine Who should get vaccinated Who should not be vaccinated How effective is the vaccine Vaccine side effects (what to expect) What is thimerosal? Why is thimerosal used as a preservative in vaccines? Do all flu vaccines contain thimerosal? Does thimerosal cause autism?

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Key Facts About Seasonal Flu Vaccine

The single best way to protect against the flu is to get vaccinated each year.

There are two types of vaccines:

• The "flu shot" - an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. The flu shot is approved for use in people older than 6 months, including healthy people and people with chronic medical conditions.

• The nasal-spray flu vaccine - a vaccine made with live, weakened flu viruses that do not cause the flu (sometimes called LAIV for "live attenuated influenza vaccine" or FluMist®). LAIV (FluMist®) is approved for use in healthy* people 2-49 years of age who are not pregnant.

The seasonal flu vaccine protects against three influenza viruses that research indicates will be most common during the upcoming season. The 2012-2013 flu vaccine will protect against 2009 H1N1, and two other influenza viruses (an H3N2 virus and an influenza B virus). The viruses in the vaccine change each year based on international surveillance and scientists' estimations about which types and strains of viruses will circulate in a given year. About 2 weeks after vaccination, antibodies that provide protection against influenza virus infection develop in the body.

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Who Should Get Vaccinated

On February 24, 2010 vaccine experts voted that everyone 6 months and older should get a flu vaccine each year starting with the 2010-2011 influenza season. CDC's Advisory Committee on Immunization Practices (ACIP) voted for "universal" flu vaccination in the U.S. to expand protection against the flu to more people.

While everyone should get a flu vaccine each flu season, it's especially important that the following groups get vaccinated either because they are at high risk of having serious flu-related complications or because they live with or care for people at high risk for developing flu-related complications:

• Pregnant women

• Children younger than 5, but especially children younger than 2 years old

• People 50 years of age and older

• People of any age with certain chronic medical conditions

• People who live in nursing homes and other long-term care facilities

• People who live with or care for those at high risk for complications from flu, including:

  • Health care workers

  • Household contacts of persons at high risk for complications from the flu

  • Household contacts and out of home caregivers of children less than 6 months of age (these children are too young to be vaccinated)

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When to Get Vaccinated

Yearly flu vaccination should begin in September or as soon as vaccine is available and continue throughout the influenza season, as late as April. Arizona's flu season typically begins around the holidays (although we're already seeing some flu now) and peaks in January or February. The flu vaccine will offer protection during the entire flu season, no matter how early you get vaccinated.

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Who Should Not Be Vaccinated

There are some people who should not get a 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.

• Children less 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).

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How Effective is the Vaccine

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. It is possible that you may get the flu even though you were vaccinated, however it will likely be much milder than it would be if you hadn't received the vaccine.

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Vaccine Side Effects (What to Expect)

Different side effects can be associated with the flu shot and LAIV.

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

If these problems occur, they begin soon after the shot and usually last 1 to 2 days. Almost all people who receive influenza vaccine have no serious problems from it. However, on rare occasions, flu vaccination can cause serious problems, such as severe allergic reactions. As of July 1, 2005, people who think that they have been injured by the flu shot can file a claim for compensation from the National Vaccine Injury Compensation Program (VICP).

The nasal spray (also called LAIV or FluMist®): 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 children, side effects from LAIV (FluMist®) can include:

• runny nose

• wheezing

• headache

• vomiting

• muscle aches

• fever

In adults, side effects from LAIV (FluMist®) can include:

• runny nose

• headache

• sore throat

• cough

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What is thimerosal?

Thimerosal is a mercury-based preservative that has been used for decades in the United States in multi-dose vials (vials containing more than one dose) of medicines and vaccines.

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Why is thimerosal used as a preservative in vaccines?

Thimerosal is added to vials of vaccine that contain more than one dose to prevent the growth of bacteria and fungi in the event that they get into the vaccine. This may occur when a syringe needle enters a vial as a vaccine is being prepared for administration. Contamination by germs in a vaccine could cause severe local reactions, serious illness or death. In some vaccines, preservatives are added during the manufacturing process to prevent microbial growth.

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Do all flu vaccines contain thimerosal?

No. Influenza (flu) vaccines are currently available in both thimerosal-containing and thimerosal-free versions. The total amount of flu vaccine without thimerosal as a preservative at times has been limited, but availability will increase as vaccine manufacturing capabilities are expanded. In the meantime, it is important to keep in mind that the benefits of influenza vaccination outweigh the theoretical risk, if any, of exposure to thimerosal.

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Does thimerosal cause autism?

Research does not show any link between thimerosal in vaccines and autism, a neurodevelopmental disorder. Although thimerosal was taken out of childhood vaccines in 2001 (with the exception of some flu vaccines), autism rates have gone up, which is the opposite of what would be expected if thimerosal caused autism. For more information on thimerosal, see
http://www.cdc.gov/vaccinesafety/Concerns/thimerosal/thimerosal_faqs.html.

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