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Health & Science

How A Lack Of Data On COVID-19 Vaccines Affects Pregnant People

ARI SHAPIRO, HOST:

Although pregnant people face a higher risk of serious disease or death from COVID-19, Pfizer and Moderna excluded anyone who was pregnant or breastfeeding from the initial clinical trials for their COVID-19 vaccines. That's fairly standard for clinical trials, but it's led many people who are pregnant to ask, is the vaccine safe for them and the baby? The CDC says it's a personal choice to discuss with your doctor.

Dr. Judette Louis is president of the Society for Maternal-Fetal Medicine. And I asked her if she regrets that the studies to date have not included pregnant and breastfeeding people.

JUDETTE LOUIS: I definitely think they should have been included. But this is part of a greater battle that we're fighting for those of us who take care of pregnant people, particularly ones that have high-risk pregnancies. Most of the treatments we use for those conditions have not been tested in pregnant people. And it's not just vaccines, it's medications in general, also.

SHAPIRO: So right now, is there any data at all on how safe and effective the vaccine might be for pregnant people?

LOUIS: There are two ways that we have a limited set of data. One was Moderna, which conducted a study in rats - in pregnant rats in particular - that found no adverse effects from that. And so certainly it's not human data, but that's what they're seeing in pregnancy. The other small set of individuals we have data in are people who were part of the Pfizer study. And even though pregnancy was an exclusion criteria, they either got pregnant soon thereafter or didn't know they were pregnant and received the vaccine. But that is a limited subset of around 23 patients, so that's not enough to give us any meaningful information.

SHAPIRO: Yeah. Now I said that the CDC recommends people discuss this with their doctor. You are such a doctor. And so if a pregnant patient came to you and said, should I get the vaccine, what would you tell them? What are you telling them?

LOUIS: So first, I will say that my answer is biased because as the president of the organization that actually advocated for the CDC to take this position, we truly believe that pregnant people need to have autonomy to make decisions for themselves. And something like this is very individualized. So when patients come to me - and I've had multiple patients discuss this with me - we've had every possible outcome. Some have chosen to get the vaccine. Some have chosen to not get it. Others have chosen to wait.

The considerations that go into that include things like your individual risk factors - like, do you have other medical conditions? How sick are you at baseline? Your occupational exposure, your household exposure - do other people in your house work in high-risk settings? Do they participate in high-risk behaviors? So for example, if you have a partner who is still going to bars where bars are open, we know that that's a potential place for contraction. And so then you may be at higher risk.

The other thing we've seen come into play is, how far are you into your pregnancy? One individual felt that she was close enough to delivery that she would just wait until after she delivered and receive her vaccine then, whereas others who were earlier in the pregnancy may have chosen to proceed because they were facing six more months of pregnancy.

SHAPIRO: I've been referring to people who are pregnant or breastfeeding, but would you expect there to be a difference in risk if there is any risk between those two groups that after the baby is born and breastfeeding, there might be less of a risk to the child than there would be while a woman is pregnant?

LOUIS: So that's what some people think. But here's the reality. We know that after you've had a COVID infection, you do form antibodies that then could be passed on to the baby that may give you some protection there. Also, if you're breastfeeding, some antibodies could potentially be passed on there. But here's the problem. We're faced with the decision to not include pregnant people and breastfeeding people in those studies, so we don't have the data to say for certain that those would be the benefits. We're extrapolating from the knowledge that we have from other vaccines and other conditions so that we apply them to people who are pregnant and breastfeeding.

SHAPIRO: Dr. Judette Louis is a maternal-fetal medicine specialist at the University of South Florida in Tampa.

Thank you very much.

LOUIS: Thank you. Transcript provided by NPR, Copyright NPR.