Taking A Pregnant Pause On Swine Flu Vaccine : Shots - Health News RIchard Knox clears up the confusion about pregnancy and the swine flu vaccine.
NPR logo Taking A Pregnant Pause On Swine Flu Vaccine

Taking A Pregnant Pause On Swine Flu Vaccine

Let's take a break for one moment from the breathless coverage of the health care overhaul on Capitol Hill to consider something else listeners are concerned about, especially the pregnant ones: Whether to get vaccinated against the swine flu.

What to consider when pregnant. istochphoto.com hide caption

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What to consider when pregnant.


FDA recently approved four new swine flu vaccines, and a fifth is in the works.

But there has been some confusion about what the estimated 3 to 4 million women who are pregnant should do.

Health Correspondent Richard Knox, who has been closely following developments on the new H1N1 virus and vaccine development, weighs in on this issue:

The swine flu vaccines are not specifically approved for pregnant women. But neither are ordinary seasonal flu vaccines.

The reason, says FDA, is that the agency doesn't specifically approve most adult drugs for categories of adults, such as pregnant adults.

If you look at the fine print on seasonal flu vaccine labels, you'll see language like this: "It is not known whether (this vaccine) can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. (This vaccine) should be given to a pregnant woman only if clearly needed."

This doesn't sound very reassuring, and it may be one reason why many obstetricians have not urged their pregnant patients to get seasonal flu vaccines.

In fact, only about 15 percent of pregnant women get the flu shot, even though the Centers for Disease Control and Prevention recommends it, Knox says. The CDC is strongly recommending that pregnant women get the new swine flu vaccine.

To further its understanding of pregnancy and vaccines, NIH recently launched a small trial of the swine flu vaccine in women in their second or third trimester.

Melissa Block of All Things Considered recently asked Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases why pregnant women should get it:

BLOCK: You know, Dr. Fauci, I'm just thinking, you know, women - pregnant women are leery of just so many things during their pregnancy: the food they eat, the vaccines they're thinking about getting. I just wonder how you confront people's fears and possible effects since much is unknown about this virus.

Dr. FAUCI: Okay. That's an excellent question - a quite reasonable question. Whenever you talk about any kind of intervention in a pharmaceutical product of any sort, what you do is you balance what we call the risk and the benefit. Pregnant women are at a considerably higher risk for the complications of this pandemic HIN1 flu or of any influenza.

And why are they at a greater risk of complications from flu, she asks?

Dr. FAUCI: Well, the risk of complications is generally two-fold. When women are pregnant their immune system becomes compromised, because the fetus is representing the genes of both the mother and the father. So there's a degree of what we call foreignness to the fetus, so that there would be a tendency to reject something that's foreign.

But Mother Nature, what it does, it allows the immune system of a pregnant woman to adapt itself to be suppressed during the time of pregnancy so that you don't have an immunological rejection of the fetus. That's one of the reasons why.

The other is, particularly in the latter time of the pregnancy, when the mass of the fetus in the abdomen creates a difficulty with the free movement of air in the lungs of women. And women, as you know, during the latter part of pregnancy do not have as good respiratory capacity as someone who is not pregnant.

Knox says six percent of swine flu cases so far have been in pregnant women, even though they represent only about 1.6 percent of the adult population. One study estimates that pregnant women have been hospitalized with swine flu four times more often than the general population. Their risk of dying from swine flu is 13 times higher.

Clearly, pregnant women and their doctors need to be convinced that flu vaccine are safe. But FDA can't say much about that, Knox says.

Except this: "There are a large number of studies which show no increased adverse outcomes to mother or newborns" from seasonal flu, one senior FDA official tells Knox. And surveillance systems that look for bad outcomes among flu-vaccinated pregnant women have found no sign of problems.

So, does this mean that pregnant women should avoid getting flu vaccine? Knox says no.There's no reason to suspect a problem from millions of vaccinations over the years.

And there is a real reason to be worried about getting swine flu while pregnant.