Pregnant Women – Which H1N1 Flu Vaccine is Right For You?

As an expectant mother, it’s natural to be concerned about your health and the health of your baby during the H1N1 flu virus pandemic. Throughout your pregnancy, you’ve probably heard a lot of advice about what to eat, how to exercise, and what to avoid to protect your baby’s health. Taking the H1N1 flu vaccine is one more thing you can do to reduce the risk that catching the H1N1 flu virus poses to your health and your baby’s health.

Pregnant women are not more likely to get the H1N1 flu virus than anyone else, but when they do get it, they are about five times more likely to be hospitalized and about three times more likely to suffer very serious complications.

To date, of the pregnant women who have been hospitalized with H1N1 flu virus, over two-thirds were in their third trimester.

Adjuvanted or Unadjuvanted – Who Gets What?

You may be hesitant about taking a vaccine to protect against H1N1 flu virus, or uncertain of which kind of vaccine is right for you.  Here’s what we know about the H1N1 flu vaccine.

There are two types of H1N1 flu vaccine: adjuvanted and unadjuvanted.  Most Canadians will receive the adjuvanted vaccine.  An adjuvant is a substance that boosts immune response.  It is made up of naturally occurring oil, water and vitamin E. The unadjuvanted vaccine doesn’t include this booster. Adjuvanted vaccine is available now across the country. Canada’s supply of unadjuvanted vaccine will be available in early November. 

• The unadjuvanted vaccine is recommended for all pregnant women at any stage of their pregnancy.

However if the unadjuvanted vaccine is not easily available, some pregnant women should consider getting the adjuvanted vaccine.

• If you are more than 20 weeks pregnant, OR if you have a chronic disease (like asthma or diabetes), you are at greater risk for severe complications from the H1N1 flu. You should consider getting the adjuvanted vaccine that is available now.

The potential benefit of early immunity to the H1N1 flu virus (from getting the vaccine) is greater than the possible risk of receiving the adjuvanted flu vaccine.

• If you are less than 20 weeks pregnant, and are healthy, you can wait to get the unadjuvanted vaccine. You are less likely than women in late stages of pregnancy or women with severe chronic disease to develop complications from influenza. Get the unadjuvanted vaccine as soon as it becomes available to you. If you want immunization with the adjuvanted vaccine, that is an option for you.

What are the Benefits…What are the Risks?

Your doctor can help you to consider your options, but the fact remains that immunization is the most effective way to prevent illness and protect your baby’s health. The benefit of immunization – preventing severe disease and death – greatly outweighs the risks associated with the vaccine.

The adjuvant in the H1N1 flu vaccine has been tested in roughly 45,000 people with no serious adverse events reported.

Unadjuvanted vaccine is recommended for use by pregnant women. Although there is no evidence that adjuvanted vaccine is unsafe for pregnant women, this kind of vaccine hasn’t been tested in pregnant women, so unadjuvanted vaccine is the first choice for pregnant women.

Unadjuvanted vaccine is made the same way as the regular seasonal flu shot, which has been used safely in pregnant women for many years.

Serious adverse events (medical problems) following influenza immunization are rare. There is usually about one serious adverse event, like a severe allergic reaction, for every 100,000 doses of flu vaccine distributed. Some adverse events, like Guillain-Barré syndrome (GBS), an illness resulting in paralysis, are even more rare. There is about one case of GBS for every million doses of flu vaccine distributed.

It’s important to note that these events were not necessarily caused by the vaccine; they are reported because the events followed immunization. Each serious adverse event reported in Canada is investigated to determine its cause.

You can find more information about vaccine safety and vaccine myths here.