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Vaccine Safety

People often have concerns over getting yearly flu shots and this year, many questions have been asked because of the new H1N1 vaccine.

How safe are these vaccines? Should I get the seasonal flu shot? The H1N1 flu shot? Both? Talk with your healthcare provider about your eligibility to get the flu vaccines.

A vaccine, like any medicine, could possibly cause problems, such as an allergy to the vaccine but the risk of a vaccine causing serious harm, or death, is extremely small.

As always, getting the influenza vaccine is voluntary, but it helps to know the facts before making this decision.

The flu vaccine is available as a killed or inactivated vaccine, also known as the “flu shot” and a live, weakened vaccine that is given as a nasal spray. Common side effects for the “flu shot” for the seasonal flu vaccine and the 2009 H1N1 flu vaccine include swelling or soreness at the injection site, headache and a slight fever. Common side effects for the “nasal spray” for the seasonal flu vaccine and the 2009 H1N1 flu vaccine include runny nose, headache and congestion.

The flu vaccines will not prevent “flu-like” illness caused by other viruses.

For additional information, please see the links at the bottom of the webpage.

Seasonal Flu

  • This year’s seasonal influenza vaccines do not contain the 2009 H1N1 strain, which is why there are two separate vaccines.
  • The “flu shot” cannot give you the flu since it contains a killed virus. The “nasal spray” flu vaccine contains a weakened virus but does not cause the flu. It typically takes 2 weeks for your body to build immunity to the flu strains, so you may still get the flu if exposed within that time.
  • Since all seasonal influenza vaccines licensed in the United States are produced in eggs, people with egg allergies should not receive the vaccine.
  • Some versions of the vaccine contain thimerosal, a preservative, to prevent contamination in bottles that contain more than one dose of the vaccine. The single dose/pre-filled syringes do not contain the thimerosal preservative.

2009 H1N1 Flu

  • The 2009 H1N1 flu vaccine will not protect you against the seasonal flu; it will only protect you from the 2009 H1N1 flu.
  • The 2009 H1N1 vaccine is manufactured and produced the same way as the yearly seasonal flu vaccine.
  • The 2009 H1N1 vaccine is also produced in eggs and should not be given to people with egg allergies.
  • Some of the 2009 H1N1 vaccine will be available without the preservative thimerosal.
  • The Centers for Disease Control and Prevention expects the 2009 H1N1 vaccine to have a similar safety profile as seasonal flu vaccines, which have very good safety track records.
  • In 1976, an earlier type of swine flu vaccine was associated with a rare disorder called Guillain-Barre Syndrome. Studies done since then have not been able to link Guillain-Barre with the seasonal flu vaccine. The Centers for Disease Control and Prevention does not expect Guillain-Barre Syndrome cases to occur after vaccination with the 2009 H1N1 vaccine. For additional information, please see the link below.

H1N1 Vaccine Recalls

There have been two non-safety-related recalls of H1N1 Influenza vaccine issued by the Centers for Disease Control and Prevention (CDC). The affected vaccine includes certain lots of Sanofi Pasteur H1N1 .25mL pre-filled syringes and certain lots of MedImmune intra-nasal spray (“Flu Mist”). Both of these recalls are due to the shelf-life of the vaccine being less than what was initially anticipated, resulting in a decrease in effectiveness of the vaccine. The manufacturers perform routine, ongoing stability testing of vaccine to make sure it does not go below a pre-specified limit during the vaccine’s “shelf-life.” Both manufacturers notified the CDC and Food and Drug Administration (FDA) when they determined the affected lots were at risk for falling below that limit.

It is important to note that doses of these vaccines were within the specified range at the time the vaccine was distributed. The slight decrease in potency should not affect how the vaccine works. The manufacturers will send providers directions for returning any un-used vaccine from the affected lots.

Persons who received vaccine from the recalled lots do not need to take any special actions. As is recommended for all 2009 H1N1 vaccines, all children younger than 10 years old should get the recommended two doses of 2009 H1N1 vaccine approximately a month apart for the optimal immune response. Therefore, children younger than 10 years old who have only received one dose of the nasal spray vaccine thus far should still receive a second dose of 2009 H1N1 vaccine. It is best to use the same type of vaccine for the first and second dose.

For more information on the vaccines, see the links below.

Centers for Disease Control Links

Seasonal Flu Vaccine Safety (CDC)

H1N1 Vaccine Safety (CDC)

Thimerosal Safety (CDC)

Guillain-Barre Syndrom Questions and Answers

2009 H1N1 Flu Vaccine and Seniors

CDC H1N1 Nasal Spray Recall Information

CDC H1N1 Sanofi Pasteur Recall Information

Vaccine Information Sheets

Seasonal Flu Vaccine “shot” Information Sheet in English

Seasonal Flu Vaccine “shot” Information Sheet in Spanish

Seasonal Flu Vaccine “nasal spray” Information Sheet in English

Seasonal Flu Vaccine “nasal spray” Information Sheet in Spanish

H1N1 Information Page

Other Links

NH Department of Health and Human Services Website

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