Vaccines During Pregnancy and Breastfeeding

What. There are two types of flu vaccine: The inactivated virus vaccine, delivered as an injection; and the attenuated virus vaccine, delivered as a nasal spray. Pregnant women should only receive the inactivated, injection form. The nasal spray vaccine is approved only for use in healthy people 2 to 49 years of age who are not pregnant.

One other thing: If you're severely allergic to eggs (the vaccine is grown in eggs), had a severe reaction to a flu vaccine in the past or are under six months of age, you should not be immunized. Also, if you have a fever, wait until you're better before getting the vaccine.

You have another consideration when it comes to the vaccine: thimerosal or thimerosal free? Thimerosal is a mercury compound that has been used for more than 80 years to preserve vaccines. Numerous studies find no harmful effects from the preservative in children or adults. Still, some people worry about it, which is why manufacturers have now made a thimerosal-free vaccine available.

Here's something else you should be aware of: The vaccine is not foolproof. It will not provide 100 percent protection against the flu. When the vaccine and the circulating viruses are similar, the vaccine can prevent the flu among 70 to 90 percent of healthy adults under 65.

Even if you do get the flu, the vaccine can still protect you against flu-related complications by minimizing the severity of the illness.

And, contrary to flu myths out there, you cannot get the flu from a flu shot or the nasal vaccine. If you get sick after a vaccine, it's just coincidence. In fact, the most common side effect of the shot is a little soreness at the injection site, and the most common side effect of the spray is a runny nose or nasal congestion.

When. The best time for a flu shot is between September and December, before flu season really peaks in January, February or later. But if the New Year rolls around and you realize you never got vaccinated, relax, it's not too late to get your flu shot. It usually only takes about two weeks for your body to make antibodies (immune system proteins that help your system recognize the flu virus) to the virus. So no matter when you get vaccinated, you still get some protection.

While a single vaccine lasts the entire season, it won't protect you next year because your immunity fades. Plus, flu viruses change from year to year. That's why it's important to get vaccinated every year.