A Flu Shot During Pregnancy Protects Baby, Too

Interviewer: A study shows just how important getting a flu shot during pregnancy really is. Up next on The Scope.

Announcer: Examining the latest research and telling you about the latest breakthroughs. The Science and Research Show is on The Scope.

Interviewer: I'm talking with Dr. Julie Shakib. Assistant professor of pediatrics at the University of Utah School of Medicine and medical director of the well-baby and intermediate nursery. Dr Shakib, if you Google flu shot and pregnancy, you'll find that there are actually some very vocal people out there who say that you should not get a flu shot if you're pregnant. Did you in part do this study to address those concerns?

Dr. Shakib: I agree it's a concern that not enough pregnant women are getting the flu vaccine during pregnancy but the key driver for why we decided to do this study is we knew we had the opportunity to look at a large dataset over a number of influenza seasons.

We also knew that we had the opportunity to look at the gold standard for flu which is laboratory confirmed influenza and infants and no one had really done that before. We saw an opportunity to contribute to what's known about how maternal immunization can affect the baby.

Interviewer: What did those things tell you?

Dr. Shakib: What we found in our research is that when mom reported influenza immunization during pregnancy, their infants were 70% less likely to have laboratory confirmed flu than moms who didn't report immunization during pregnancy. Additionally we found that in the same cohort of women who did and did not report immunization, that moms who did report immunization their infants were 81% less likely to have influenza hospitalizations in their for six months of life.

Interviewer: Those are both indicators that these infants are not getting the flu if their mothers get the flu shot during pregnancy. That there's a benefit to the infant from the mom's flu shot. Why is that particularly important for the in the infant and for the mother?

Dr. Shakib: That's a great question. The reason it's important is because immunization against flu isn't indicated in newborns until they're six months of age. That's because the vaccine just isn't effective in that first six months. So maternal immunization is one of the only ways we have to provide the baby with some protection until they're old enough to receive and get benefit from the vaccines themselves.

Interviewer: What happens when infants get the flu? Is it worse for them than for say you or me?

Dr. Shakib: It is. It's much worse in the first year of life than it is for adults. They're much more likely to be hospitalized for flu. Much more likely to have complications such as pneumonia. They have higher rates of morbidity and mortality from flu than older age groups do.

Interviewer: Do we know how long the mother's immunization protects the baby after it's born?

Dr. Shakib: That's another interesting question. We do know that it's dependent on when the mom received the vaccine during pregnancy. But the mom needs to get the vaccine as soon as it's available during her pregnancy. That's not something that can be timed to be exactly right for the infant.

Interviewer: Well and of course I mean, we all know that not every flu shot works. The flu changes every year and so getting a flu shot doesn't necessarily guarantee that you're going to protect the baby?

Dr. Shakib: The one thing I would say about our study that's really interesting is that even though we looked over nine seasons of influenza data, we still saw a benefit. We know every year the vaccine isn't a perfect match. What I would suggest is there is protection. How perfect it is, no vaccine is perfect, no protection is 100%. But some protection from a serious illness that we couldn't get otherwise, is the purpose of immunizing during pregnancy.

Interviewer: How did you do the research?

Dr. Shakib: Essentially we did a data analysis of nine seasons of influenza, we basically retrieved all the records and looked at documentation for whether moms reported receiving flu vaccine versus those who didn't and then compared the specific outcomes including influenza like illness, laboratory confirmed flu and flu hospitalizations in infants based on their mom's immunization status.

Before the H1N1 pandemic a lot of women were not receiving the flu vaccine. So we had a number of years where we had low immunization rates and moms that changed thankfully a fair amount with H1N1 but didn't change enough because still only about 50% of women report getting the flu vaccine during pregnancy.

Interviewer: Pregnant women, are they particularly susceptible to flu?

Dr. Shakib: They're not more likely to get the flu, but they are more likely to have some severe outcomes from the flu because of changes to their immune system, their circulation during pregnancy. So we saw with H1N1 pandemic that pregnant women were disproportionately sicker and more severely affected. Flu vaccine is a little bit of a two for one benefit. Moms need to be protected while they're pregnant, but they're also providing protection to their baby with the same shot.

Interviewer: What's kind of the main message you want to get across?

Dr. Shakib: I think that the key message is that we need to take every opportunity to both support and provide flu vaccine to pregnant women during their pregnancy. Obstetricians, midwives, nurse practitioners, anyone who cares for pregnant women needs to actively endorse and offer flu vaccine to their patients. Patients need to feel empowered to ask for it if they haven't been offered it during their pregnancy.

Announcer: Interesting, informative, and all in the name of better health. This is The Scope Health Sciences Radio.