Centers for Disease Control Q and A

Why does the CDC advise pregnant women to receive the 2009 H1N1 flu vaccine?

A pregnant woman who gets any type of flu has a greater chance for serious health problems. Compared with people in general who get 2009 H1N1 flu, pregnant women with H1N1 are more likely to be admitted to hospitals and also are more likely to have serious illness and death from H1N1.

Research has found that pregnant women who had a flu shot get sick less often with the flu than do pregnant women who did not get a flu shot. Babies born to mothers who had a flu shot in pregnancy also get sick with flu less often than do babies whose mothers did not get a flu shot.

Are there flu vaccines that pregnant women should not get?

The seasonal and H1N1 flu vaccines can be given by shot or nasal spray. The nasal spray is not approved for pregnant women because the vaccine is made with live, weakened flu virus. The shot is made with a killed flu virus. Nasal spray flu vaccines should only be used in healthy people ages 2-49 who are not pregnant but it is considered safe for women after they have delivered, even if they are nursing.

Can the seasonal and H1N1 flu vaccines be given at the same time?

Yes, they may be given on the same day but should be given at different sites on the body.

Is the H1N1 flu vaccine safe for pregnant women?

The H1N1 vaccine is being made the same way and at the same places where the seasonal flu vaccine is made, which has been given to millions of pregnant women over many years. Flu shots have not been shown to cause harm to pregnant women or their babies.

What studies have been done on the 2009 H1N1 flu shot and have any been done on pregnant women?

Studies to test the H1N1 flu shot in healthy children and pregnant women are being conducted now by the National Institute of Allergy and Infectious Diseases.

Does the H1N1 vaccine have mercury in it?

There is no evidence that thimerosal (a mercury preservative in vaccines that come in multi-dose vials) is harmful to a pregnant woman or a fetus. However, because some women are concerned about thimerosal during pregnancy, vaccine manufacturers are making preservative-free seasonal flu vaccine and H1N1 flu vaccine in single dose syringes for pregnant women and small children. The CDC advises pregnant women to get flu shots either with or without thimerosal.

Does the H1N1 flu shot have an adjuvant or squalene in it?

Adjuvants are agents that are sometimes added to a vaccine to make it more effective. There are no adjuvants (such as squalene) in either the seasonal or H1N1 flu vaccines.

Should the H1N1 flu shot be given to a pregnant woman who has had the flu between April 2009 and now?

A pregnant women who had flu-like illness at any time in the past should still get the H1N1 shot because she cannot assume that the illness she had was caused by the H1N1 virus.

What are the possible side effects of the H1N1 flu shot?

They are expected to be like those from seasonal flu shots. The most common side effects are mild, such as being sore and tender and red and swollen at the injection site. Some people might have headache, muscle aches, fever and nausea or feel tired. Some flu shots can cause serious problems like severe allergic reactions but those are very rare. A person who has a severe allergy to eggs or to anything else in the vaccine should not get the shot, even if she is pregnant.

Is the H1N1 flu shot expected to be associated with Guillain-Barre Syndrome?

In 1976, an earlier type of swine flu vaccine was associated with cases of this severe paralytic illness at a rate of about 1 case per 100,000 people vaccinated. Some studies done since 1976 have shown a small risk of GBS in people who receive the seasonal flu vaccine, or about 1 case per 1 million people vaccinated. Pregnant women should tell the person giving the shots if they have ever had GBS.

Can family members of a pregnant woman receive the nasal spray vaccine?

Yes.

- Source: Centers for Disease Control and Prevention (For more information, visit www.cdc.gov/h1n1flu/pregnancy or www.flu.gov)