Breastfeeding, Transferred Immunity, and Infant Disease Prevention with Dr. Anne-Marie Rick

About The Newborn Research Support Service (NuRSERy) | University of Pittsburgh Clinical and Translational Science Institute

COVID-19 Vaccines While Pregnant or Breastfeeding | The Centers for Disease Control and Prevention

Lactation Services at UPMC Magee-Womens Hospital | UPMC.com

Breastfeeding Benefits Your Baby’s Immune System | HealthyChildren.org from the American Academy of Pediatrics

Breastfeeding During the COVID-19 Pandemic | HealthyChildren.org from the American Academy of Pediatrics

Newborn Medicine | The University of Pittsburgh School of Medicine

Newborn Medicine Research | CHP.edu

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Voiceover: This podcast is for informational and educational purposes only. It is not medical care or advice. Clinicians should rely on their own medical judgements when advising their patients. Patients in need of medical care should consult their personal care provider. Welcome to "That's Pediatrics", where we sit down with physicians, scientists, and experts to discuss the latest discoveries and innovations in pediatric healthcare.

Dr. Amanda Poholek: From UPMC Children's Hospital of Pittsburgh, welcome to "That's Pediatrics" I'm your co-host, Amanda Poholek, from the Division of Pediatric Rheumatology and the Department of Immunology.

Dr. Arvind Srinath: And I'm your co-host, Arvind Srinath, from the Division of Gastroenterology.

Dr. Poholek: Today, our guest is Dr. Anne-Marie Rick. Dr. Rick is an expert in newborn clinical care at both UPMC Children's Hospital of Pittsburgh Primary Care Center and UPMC Magee-Women's Hospital. Her research is focused on infectious disease related to maternal infant health with active studies related to newborn sepsis, perinatal transmission of COVID-19 infections, and passive immune protection from maternal immunization during pregnancy, including influenza. She's also the director of nursery, where she works collaboratively with numerous investigators across the school of health sciences to facilitate and implement clinical research in the newborn setting. Welcome, Dr. Rick. We're so excited to have you here today.

Dr. Anne-Marie Rick: Yes, thank you for having me.

Dr. Poholek: So can you just start by telling us a little bit about your training and how you got interested in infectious disease related to maternal infant health?

Dr. Rick: Yes, I'd love to. I love telling the story. So I entered medicine really knowing that I wanted to do more public health related work and that was kind of my whole focus even on day one of medical school. And that really came from some experiences during college in a global health setting and knew that that was where I wanted a broader impact beyond the patient level. So then during my medical school and then my pediatric residency, I really took some opportunities to do some work in Guatemala and other settings where the maternal infant health aspects really just kept coming up over and over again.

So when we were in Guatemala, we were doing some work around Group B streptococcus, which is a common infection that can cause sepsis in infants. And during that time, and during that research, I first became aware of the Group B strep vaccine that's in development for moms to be given during their pregnancy to protect infants against sepsis. And when I first learned about that, my mind was blown. I thought that that was the coolest idea because you could not only protect mothers through immunization, but also make an impact on the infant. And from a public health perspective and a global health perspective, that is huge because often these are resource limited countries that may not have the same screening abilities as places with more resources.

And so immunizations offer a huge opportunity to impact that public health. So once I learned about that, I knew that that was gonna be the direction I was headed with my research one way or the other looking at how can we really leverage maternal protection for the infant and protecting infants from infectious disease.

Dr. Poholek: Yeah, this is such a fascinating topic. So can you start by just telling us a little bit about what we know about how we can protect from infectious disease using that maternal infant relationship? What are the different mechanisms by which that happens?

Dr. Rick: Yes. So it's a great question because there's some things that we understand pretty well and then there's so much that we are still learning and we don't understand. I like to think of it as being three ways that moms can protect babies.

The first is what we often describe as cocooning effect so meaning that if a mom is protected against an infectious disease and she's less likely to get that infectious disease, then the infant is less likely to be exposed to that bacteria, virus, whatever you may call maybe the situation. And so by building that protection around the infant, you decrease that risk to the infant.

The second way that moms can protect babies is by either having their own immunity either through natural exposure or through immunization, where they develop antibodies to either the bacteria or the virus, and then those antibodies can cross across the placenta into the infant. And depending on the type of bacteria or the virus, those antibodies can persist up to a year, a year and a half after delivery. Sometimes it's shorter and more three to six months, but sometimes it's a very long time. And we think that those antibodies, once they're in the baby can actually offer a degree of protection against either a virus or a bacterial infection.

The third way, and this is really where a lot of my research is focused because it's been very understudied thus far is the protection that can be provided from breast milk. We have a long history of research related to how breast milk can protect against gastrointestinal illnesses in infants such as with rotavirus or norovirus that breast milk can really help reduce the incidence of that. But in terms of how breast milk can protect against respiratory viruses, it's much less studied and much more variable in the literature. And specifically what I'm interested in is how immunizations in mom can lead to antibodies passing in the breast milk and potentially protecting infants through their exposure.

Dr. Srinath: So that's a great point and a great segue is what do we know thus far about immunizations in mothers and how they impact infants and how much immunity they do confer?

Dr. Rick: Right. It's a challenging question to answer. So what we do know is that, we'll take the flu vaccine because I think that that's probably our most studied vaccine during pregnancy as well as during lactation. So what we know is when a mom is immunized either during pregnancy or while she's lactating, that those antibodies do cross the placenta. So specifically, IgG antibodies cross the placenta into the infant and can last, as I said, up to several months in the baby's body so much so that that's one of the reasons why we've delayed flu immunizations until six months. That's how they were studied because there was concern that there would be interference from mom's antibodies in those first few months. So when they were developing the flu vaccine, that's one of the reasons why they chose that timeframe to study it.

And we also know that those antibodies cross into breast milk, and importantly, in breast milk you can actually get IgM, IgG, and IgA antibodies. So much more robust antibodies present in breast milk. What we don't know is what level of antibody is needed to actually confer that protection that we need for an infant. So we know they're there, we know they likely serve a really important role, but how much do you actually need to protect a baby is unknown. And that's actually one of the goals of my research is to really try and drill down at that and understand. Because once we understand that, we can leverage it and really think about how we vaccinate moms and whether or not they should have different immunization schedules or different ways, or different types of vaccines because maybe we're trying to do a different thing with our protection compared to a non-pregnant or a non-lactating person.

Dr. Srinath: So if that's the case to the point where at times we're delaying flu vaccinations, for example, in infants up until six months because we thought that they have protective immunity from their moms, is there a certain critical time period where the infant's immunity is less than what it was when they were born? And when is that time period in theory?

Dr. Rick: Yeah, well, so truly the infant is vulnerable even from day one, and I would say, regardless of whether a mom is immunized or not, it's just that that's how the flu vaccine was studied and that's why they chose to wait until six months. So I think we still have to think about even if a mom's immunized, I would still think of that as a highly vulnerable child in those first six months because they don't have primary protection from their own immunization. So just to clarify that, it's just that's how they chose to study the vaccine, not that we think that they're fully protected in those first few months.

But I would say, in terms of when do we think, so we do get these nice antibodies that cross the placenta, when do we think those are really waning off and maybe the infant is at their highest risk? So for the most part, we think antibodies are robust in the first two to three months of life. And then really after three months is when we start to see that dropping off.

Again, we don't know which level is needed to actually protect in that age group. But the thought is there is some data that says that even compared to adults, children need a higher level of antibody to get protection, to get the same level of protection as an adult. And so likely even with those, with our current vaccines and current antibodies, even with those that cross the placenta, we're still probably a little bit under where a primary immunization would get you.

Dr. Poholek: Okay. So you're researching this really important question about how protection from antibodies plays a role in respiratory infection, and along comes COVID-19, a respiratory infection. So can you tell us a little bit about what your research prior to that had informed us about COVID-19 and going forward? And what you may have been able to learn in the last two years using COVID-19 as a respiratory infection, what do we now understand that we didn't understand before?

Dr. Rick: Yeah. Not that COVID has brought so many bad things to our lives, but in my case, I happen to be the right person at the right place and the right time whenever the pandemic came from this perspective.

So I was really just starting to get our flu studies to really look at this going, so really was in the very beginning phase of this whenever the pandemic started. And so because of that and the research shutdowns, we actually just shifted everything to COVID-19. So I actually know more about COVID-19 at this point in time in terms of milk and blood protection than I would say even with flu at this point.

So what we have learned, we've had a couple of different studies going on during this time and it's been replicated in other places as well even outside of University of Pittsburgh. So we have seen that when moms have COVID-19 infection either during pregnancy or while they're lactating, we do see fairly robust antibodies coming through the breast milk or into the infant's blood if the mom's pregnant during that infection and we see those IgG antibodies. What we seem to see is there's more of an IgA response in the breast milk compared to an IgG response, which is important because those antibodies do different things. We think of IgA as providing us more of a mucosal protection so meaning kind of lining the upper respiratory tract and potentially protecting from an infection entering the respiratory tract. And so we're seeing more of those in breast milk after moms get an infection.

When you compare that to if a mom gets vaccine, we still see those antibodies coming through in the breast milk, but it's a much more of an IgG response compared to an IgA response. And that makes sense because those vaccines, that's what they were really meant to do was to develop an IgG response, which is what we need in our blood. So it's fascinating because it's completely different in terms of how it may play out in the child, though we don't really understand yet is one better or worse than the other or more important than the other. And I think that's the point that we're at is really trying to tease those things out.

Dr. Poholek: Sorry.

Dr. Srinath: Oh, after you, go ahead.

Dr. Poholek: So it sounds like then there's some interesting things that either a pregnant mom or a lactating mom needs to think about in terms of protecting themselves from infection or about vaccination. Can you share a little bit about the guidelines at this point and recommendations for women who are pregnant and women who are breastfeeding?

Dr. Rick: Absolutely. So I think most importantly is we know that pregnant women are at higher risk of complications from COVID-19 infection. We know that they're at higher risk of having intubation, having ICU stays, and a significantly higher risk of having a preterm birth or even a still birth. And so most importantly, those moms need to protect themselves from getting infected.

Now, fortunately, we're coming out of Omicron and having a lower transmission rate here in Allegheny County. So that's a fortunate thing, but we don't know what's coming down the pipe with this pandemic.

So vaccination is our best defense against SARS‑CoV‑2 infection. And so absolutely, I would recommend vaccination for both pregnant and lactating moms. Looking at the data there, we have no concerns for safety, even with first trimester, or second trimester, or third trimester vaccinations, there's no reason to think that it can cause preterm birth or cause any significant harm to the fetus as it's developing.

We also know that there's no concern for fertility issues or affecting women's future ability to conceive. And so really there's universal recommendation for moms to get vaccinated even if they're pregnant or lactating.

And so we know that by moms getting those vaccines on board, it significantly reduces their risk of getting virus, which means it's a much lower risk that that virus can pass through the placenta to the fetus, but also a lower risk of transmitting it to the infant once the baby is born. And so those are really key features to protecting the baby.

In terms of specific recommendations beyond that, if a mom is infected, she should be masked, but there's no reason that she can't directly breastfeed her baby or express her milk and still provide that to the infant. In fact, we would still strongly encourage that because that bonding between mother and baby is really important.

And certainly, any lactating mom knows that when they have that direct skin to skin contact with their baby, it provides lots of good endorphins that can help when you're sick as well. We certainly encourage moms to stay really well hydrated though to help with their lactation during that time. And otherwise, just good hand washing and really trying to keep things clean as much as possible.

In terms of vaccines while lactating, I've had some moms have concerns, well, can the vaccine pass through the breast milk into the infant? And there's no data to suggest that the vaccine itself passes into the breast milk. It's just those antibodies that your body produces that passes into the milk. And to be quite honest, even if there was a little vaccine that passed in there, the early pediatric studies show that it's quite safe and there's really no reason to be concerned that it might harm the child.

Dr. Srinath: Thank you. And in closing, if you could just list your top two areas of uncertainty with regards to maternal infant health, breastfeeding surrounding COVID-19 vaccination.

Dr. Rick: So I think my levels of uncertainty are more how can we really use what we have, the tools that we have, to actually protect those infants? So I wonder about things like should pregnant women and lactating women perhaps have different recommendations for vaccines compared to non-lactating or non-pregnant people with the aim of not only protecting mom, but also how can we protect that infant?

So for example, perhaps if a mom is vaccinated early in pregnancy, we should really be encouraging those moms to get a booster vaccine at the end of pregnancy or early in lactation to really augment protection for the infant. That's an area of question that I have and really we have no data to say one way or the other.

So those are the kinds of areas of uncertainty that I have. And how can we really focus on this group that is still so vulnerable because we don't have a vaccine? And honestly, for the zero to six month group, I don't know when we're gonna have a vaccine for that group specifically. So I think there's still a lot of work to be done there.

And we have an amazing combined program with medicine and pediatrics. That's a four year training program incorporating internal medicine and general pediatric training.

Dr. Poholek: This is such exciting research and we are so happy to have you as part of our UPMC Children's Hospital family, and especially for you to spend the time here to share with us the things that you're working on and your findings, and the importance of that to our moms in the community. Thank you so much for your time today.

Dr. Rick: Yes. Thank you.

Dr. Srinath: I echo my co-host. So appreciate your time and this insightful thought process and discussion of questions that I think a lot of us are asking and learning about too. Thank you.

Dr. Rick: Thank you.

Dr. Poholek: Thank you.

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