Skip to content

Pertussis Vaccination in Every Pregnancy: Safe and Effective

I’m now 37 weeks pregnant, and it blows my mind how quickly this pregnancy has flown by. Now the days are ticking by faster than I can tick things off of my to-do list, and I can feel my body warming up for birth with increasing Braxton Hicks contractions and the baby dropping into my pelvis.

Preparing for a new baby means lots of things to me. There is the physical preparation of washing and folding tiny clothes and setting up baby’s space for changing and sleeping (in our bedroom for now). There is the arduous task of coming up with names – two of them, since we don’t know the baby’s sex. There is the mental preparation of imagining life with a new baby, trying to map out a few strategies for coping with wakeful nights and baby-filled days. There are the talks with Cee about how things will change and how they will stay the same, how she can help us with the baby, and how we’ll help her to adapt to the change in her life.

There’s also the very important aspect of making sure that we do everything we can to protect our new baby’s health, especially before the first round of immunizations at 2 months. This baby will be born during the season of flu and cold viruses, and this year is predicted to be a pretty bad one for the flu. Just south of our home in Oregon, California has so far recorded nearly 10,000 cases of pertussis, also known as whooping cough, this year, more than they’ve seen in 70 years. Cee will be exposed to a range of pathogens in preschool, and my husband will encounter them in his job in healthcare. We’ll do our best to protect our baby by leaving our shoes at the front door, changing clothes when needed, and washing our hands frequently. I also plan to breastfeed, which should confer some passive protection to the baby. However, some of the most important protection has hopefully already been given to this baby during pregnancy, because I’ve been vaccinated for both the flu (as soon as the vaccine was available this season, around 26 weeks) and pertussis around 34 weeks.

Getting vaccinated for flu and pertussis during pregnancy can protect your baby from these serious illnesses during early infancy.

Getting vaccinated for flu and pertussis during pregnancy can help protect your baby from these serious illnesses during early infancy.

The flu vaccine was first recommended for pregnant women in 1964,1 and there is a large body of research showing that the flu shot is safe in pregnancy and an effective way of preventing flu infections in expecting moms, which can pose a significant risk to the fetus. There’s also good evidence that influenza antibodies are transferred to the baby in utero,2 reducing baby’s chances of infection and hospitalization with the flu in early infancy.3,4 (Several of the above links direct you to evidence-based articles written by Tara Haelle on her blogs at Red Wine and Apple Sauce and Forbes. If you want to keep up with vaccine and other health news, Tara is an excellent blogger and science journalist to follow.)

The latest news on this year’s flu season is showing that most of the cases seen so far have been identified as being caused by seasonal influenza A H3N2, a nasty strain, and about half of these are a new subtype that isn’t well-covered by this year’s flu vaccine. If you haven’t yet gotten a flu shot this season, don’t let this news deter you. The flu vaccine will still protect you from the older strains of the flu and might decrease the severity of an infection with the newer type. The vaccine is very safe and still offers the best protection against the flu for you and your baby.

The recommendation that women be vaccinated against pertussis in every pregnancy – using the Tdap vaccine here in the U.S. – was new in 2012. It wasn’t recommended when I was pregnant with Cee in 2010, although I had recently gotten a Tdap booster for my job at the time. Several pregnant friends and readers have emailed me this fall asking if Tdap in pregnancy is safe and if they really need it, particularly if they were just vaccinated in the last couple of years. The good news is that there have been quite a few studies published on these questions in just the last year or two, and I’ll focus the rest of this post on the evidence for the Tdap shot in pregnancy.

What is the concern about pertussis in young infants?

We’ve seen big increases in pertussis recently, especially over the last decade. In 2012, there were more than 48,000 cases reported in the U.S., making it the worst year since 1955. Pertussis hits young infants the hardest. Among the 20 deaths from pertussis in the U.S. in 2012, 15 were in infants less than 3 months of age [PDF]. The first dose of pertussis vaccine is usually given with the DTaP shot at 2 months of age, and before this time, infants are particularly vulnerable to the disease. The 2012 recommendation that women be vaccinated with Tdap in the third trimester of every pregnancy came in response to these infant deaths, the hope being that maternal antibodies to pertussis could help protect infants during those first few months of life.

Previous to the recommendation to vaccinate during pregnancy, pertussis prevention strategies were focused on “cocooning” infants. That meant vaccinating women just after giving birth and also trying to vaccinate family members and others around them to decrease newborns’ exposure to pertussis. While this strategy made sense, research has shown that it isn’t particularly effective at protecting infants from pertussis. It can take several weeks for pertussis antibodies to peak in moms after vaccination, leaving mom and baby vulnerable during the first few weeks postpartum, and it can be challenging (and expensive) to get everyone in contact with the baby vaccinated. It certainly doesn’t hurt to ensure that the family is up-to-date on their pertussis vaccines, and some studies suggest that it helps a little, but overall, it’s turned out to be a pretty inefficient strategy. Tara Haelle reviewed some of the latest research on cocooning here.

Is there evidence that Tdap vaccination in pregnancy can protect babies from pertussis?

The strategy of vaccinating moms during pregnancy takes advantage of the natural transfer of mom’s antibodies to the fetus across the placenta. Several recent studies show that this is an effective way to boost baby’s immunity. Given the pertussis outbreaks in recent years and the finding that cocooning offers only minor protection, this is pretty great news.

A small randomized controlled trial led by Flora Munoz of Baylor College of Medicine, published in JAMA in May of this year, gave 33 women Tdap and 15 women a placebo at 30-32 weeks of pregnancy.5 After giving birth, the treatments were crossed over so that the women receiving the vaccine during pregnancy received the placebo postpartum and vice versa. Predictably, the moms who received the vaccine during pregnancy had higher antibody levels in their blood at the time of delivery, and this was also reflected in their infants at birth and at 2 months of age. Researchers measured antibodies to 4 different proteins produced by the Bordatella pertussis bacterium, and depending on the protein, levels were 5x-36x higher in infants whose moms were vaccinated in pregnancy compared to those who weren’t.

Although the Munoz study was small, it very convincingly demonstrated that vaccination in pregnancy confers greater anti-pertussis antibodies to infants. What it couldn’t do was tell us whether these antibody levels actually protect infants from pertussis infection in the first few months of life. To answer this question, we need much larger groups of study subjects, which means turning to epidemiological studies.

That’s where a study from the U.K., published in the Lancet in October of this year, comes in.6 As in the U.S., there was a huge pertussis outbreak in the U.K. in 2012, during which 14 infants died. In September of that year, the U.K. Department of Health recommended that pregnant women receive the acellular pertussis vaccine between 28 and 38 weeks of pregnancy. In the subsequent year, about 60% of pregnant women were vaccinated.

The Lancet study tracked confirmed pertussis cases occurring in infants younger than 3 months before and after this new recommendation and then looked back at their mothers’ vaccination records to see if vaccination in pregnancy affected their chances of infection.6 The results were impressive. Of 82 pertussis cases in young infants, most were born to women who didn’t receive the vaccine during pregnancy. Only 12 of them (15%) were born to mothers vaccinated at least one week before giving birth. The researchers calculated that the pertussis vaccine was 91% effective in preventing pertussis in young infants, so long as it was given at least 7 days before birth. If the vaccine was given less than 7 days before birth or in the immediate postpartum period, vaccine effectiveness dropped to 38%.

This last part about the timing of the vaccine is important, and it explains in part why the recommendation is to receive the vaccine during the third trimester of every pregnancy. After vaccination, it takes a couple of weeks for anti-pertussis antibodies to peak in the mom,7,8 which is why it is important to vaccinate well before your due date. However, it’s also important not to vaccinate too early. After the antibody peak, circulating pertussis antibodies seem to drop pretty quickly. When women are vaccinated before pregnancy or early in pregnancy, the pertussis antibody concentrations found in cord blood appear to be too low to provide much protection to the infant and are much lower than those found in women vaccinated in the third trimester.5,9 (This doesn’t mean that mom can’t mount an effective immune response to pertussis if exposed, just that circulating antibodies available to cross the placenta are low.) In general, maternal IgG antibodies are not transported across the placenta very efficiently until the third trimester, so to optimize placental transfer to the baby, we want mom’s antibody concentrations to peak during that time.10

Maternal vaccination during pregnancy is an elegant solution to the problem of this deadly disease in newborns. It allows us to give mom a small, controlled dose of inactivated pertussis toxoids at an optimal time in late pregnancy, and the baby gets the benefit of being born with at least temporary immunity to pertussis, enough to protect her during early infancy until she can receive her own vaccine around 2 months.

Is there evidence that Tdap vaccination in pregnancy is safe for the mom and baby?

Two studies out this year provide reassuring data on the safety of Tdap in pregnancy. Tara Haelle (again!) wrote about both of these here and here, so I’ll mention these findings only briefly. A U.K. study, published in the BMJ in July, compared pregnancy and birth outcomes in more than 20,000 women who received the pertussis vaccine in the third trimester to a matched group of unvaccinated pregnant women.11 There were no differences between the vaccinated and unvaccinated groups when it came to risk of stillbirth, maternal or neonatal death, pre-eclampsia or eclampsia, hemorrhage, fetal distress, uterine rupture, placenta or vasa previa, cesarean birth, low birth weight, or neonatal renal failure.

A more recent study, published last month in JAMA, looked back at more than 123,000 women in California’s Kaiser health system, 21% of whom had received Tdap during pregnancy.12 In this study, there were no differences in risk of small-for-gestational age birth, preterm birth, or hypertensive disorders in pregnancy between vaccinated and unvaccinated women. Vaccinated women were slightly more likely to be diagnosed with chorioamnionitis (6.1%), a bacterial infection of the fetal membranes, compared with unvaccinated women (5.5%). Tara Haelle explained why we shouldn’t freak out about that finding in her post on the study (the association is likely due to confounding factors that weren’t considered in the study).

Finally, the randomized controlled trial conducted by Munoz et al, which included the antibody data mentioned earlier, also included a detailed assessment of reactions to the vaccine as well as birth and baby outcomes.5 This study found no difference in birth weight, gestational age, Apgar scores, neonatal exams, birth complications, or the baby’s growth and development later in infancy. Pain at the injection site of Tdap was common – occurring in about 3 out of 4 women – and more frequent than found in the placebo group, but symptoms were generally mild and resolved on their own within a few days. (This was also my experience – a sore arm for a couple of days.)

What’s the bottom line? Receiving the Tdap vaccine during the third trimester of pregnancy is our best chance at protecting young infants from pertussis, a disease that can be particularly dangerous during the first few months of life. Research shows that vaccination in late pregnancy gives newborns the gift of pertussis-specific antibodies at birth and is safe for both mother and baby.

References:

  1. Keener, A. B. Efficacy studies build up the case for prenatal immunization. Nat. Med. 20, 970–972 (2014).
  2. Steinhoff, M. C. et al. Influenza Immunization in Pregnancy — Antibody Responses in Mothers and Infants. N. Engl. J. Med. 362, 1644–1646 (2010).
  3. Zaman, K. et al. Effectiveness of Maternal Influenza Immunization in Mothers and Infants. N. Engl. J. Med. 359, 1555–1564 (2008).
  4. Benowitz, I., Esposito, D. B., Gracey, K. D., Shapiro, E. D. & Vázquez, M. Influenza Vaccine Given to Pregnant Women Reduces Hospitalization Due to Influenza in Their Infants. Clin. Infect. Dis. 51, 1355–1361 (2010).
  5. Munoz FM, Bond NH, Maccato M & et al. Safety and immunogenicity of tetanus diphtheria and acellular pertussis (tdap) immunization during pregnancy in mothers and infants: A randomized clinical trial. JAMA 311, 1760–1769 (2014).
  6. Amirthalingam, G. et al. Effectiveness of maternal pertussis vaccination in England: an observational study. The Lancet 384, 1521–1528 (2014).
  7. Kirkland, K. B., Talbot, E. A., Decker, M. D. & Edwards, K. M. Kinetics of Pertussis Immune Responses to Tetanus-Diphtheria-Acellular Pertussis Vaccine in Health Care Personnel: Implications for Outbreak Control. Clin. Infect. Dis. 49, 584–587 (2009).
  8. Halperin, B. A. et al. Kinetics of the Antibody Response to Tetanus-Diphtheria-Acellular Pertussis Vaccine in Women of Childbearing Age and Postpartum Women. Clin. Infect. Dis. 53, 885–892 (2011).
  9. Healy, C. M., Rench, M. A. & Baker, C. J. Importance of timing of maternal combined tetanus, diphtheria, and acellular pertussis (Tdap) immunization and protection of young infants. Clin. Infect. Dis. Off. Publ. Infect. Dis. Soc. Am. 56, 539–544 (2013).
  10. Glezen, W. P. & Alpers, M. Maternal immunization. Clin. Infect. Dis. Off. Publ. Infect. Dis. Soc. Am. 28, 219–224 (1999).
  11. Donegan, K., King, B. & Bryan, P. Safety of pertussis vaccination in pregnant women in UK: observational study. BMJ 349, g4219–g4219 (2014).
  12. Kharbanda EO, Vazquez-Benitez G, Lipkind HS & et al. Evaluation of the association of maternal pertussis vaccination with obstetric events and birth outcomes. JAMA 312, 1897–1904 (2014).

Save

47 Comments
  1. reissd #

    Thank you for providing this information!

    Like

    December 10, 2014
  2. Reblogged this on To Talk of Many Things and commented:
    Good Thoughts for those pregnant women wondering about vaccines.

    Like

    December 10, 2014
  3. b #

    Thanks! I did read Tara Haelle’s pieces previously, but it’s helpful to hear it from your perspective/review as well.

    Like

    December 10, 2014
  4. Alice #

    I know you underlined it above – about getting the vaccine during EVERY pregnancy – but I feel like I’ve heard that the Tdap is “good for” either 5 or 10 years. So if I had it, say, three years ago, should I get it again during my third trimester? (I’m pregnant now)

    Like

    December 10, 2014
    • Yes, the recommendation is really to get it in EVERY pregnancy. If you were vaccinated 3 years ago, you probably still have protection for yourself, but you don’t have high levels of antibodies in your blood to pass on to your fetus. Getting the booster late in pregnancy allows you to pass on that protection to your baby as well. Definitely talk to your OB about it, but based on the studies I cite in the post, every pregnancy is the way to go.

      Like

      December 10, 2014
      • Alice #

        So interesting! I will definitely share this with my midwife. Thanks!

        Like

        December 10, 2014
  5. I would have to respectfully disagree. Vaccinations rarely provide protection from viruses. You will still get sick and the vaccine only activates your immune system and does nothing else. Studies have shown that vaccines are more harmful than beneficial. If you are pregnant, please do not get vaccinated for the sake of your baby and yourself.
    My wife is pregnant with our second child and they have never been vaccinated and they are more healthy than others who have been vaccinated. I don’t want to cause an argument here. I just want to share my opinion. Thanks!

    Like

    December 10, 2014
    • I have read quite a few vaccine studies, and I haven’t found any that provide evidence to support your claims. Please provide citations to peer-reviewed research, because that is the focus of this blog. As a pregnant mother doing my best (thanks to science!) to protect my newborn, I’m simply not convinced by your opinion. I look to science to inform my healthcare decisions, and I think the scienceon this question , as laid out in my post, is convincing.

      Like

      December 10, 2014
  6. Interesting and informative article that should help parents who are awaiting the birth of a child and those thinking about pregnancy with their decision making. Parents need information but ultimately the decision is theirs and they have to learn to trust it. That what I like about your article. Hope the rest of your pregnancy is good, your baby is healthy and the life ahead for all you is what you want it to be.

    Like

    December 10, 2014
  7. Just reading Moonkin & Offit on the vaccination issue. Depressing reading but it is good to hear that there are some bloggers offering useful & sound advice. Thanks Alice.

    Like

    December 10, 2014
  8. Claire S #

    Thank you for this informative overview of the recent literature. Do you know if any companies are considering a pertussis only vaccine? Diphtheria and tetanus don’t seem to be huge concerns in newborns in developed countries.

    Liked by 1 person

    December 10, 2014
    • It’s a great question. I haven’t read anything about a pertussis only vaccine but haven’t looked specifically for info on its development. I’m sure it could be done, but I’m not sure how motivated a pharmaceutical company would be to do it, particularly since the tetanus vaccine is used so routinely in pregnancy around the world with a great safety record. I can see how a pertussis only vaccine might be more acceptable to women in the U.S., however.

      Like

      December 10, 2014
  9. Grace #

    What do you mean the flu vaccine was first recommended for pregnant women in 1964? I cannot find any evidence to support that claim. Also, none of the safety studies you mentioned record any long-term effects on a fetus who was exposed to a vaccination in the womb. Obviously that kind of data cannot be recorded yet because these recommendations for prenatal vaccines are so new. In any case, I am not willing to let my unborn baby be a guinea pig of the medical community and feel just fine not getting either of these vaccines.

    Like

    December 10, 2014
    • Hi Grace,

      The reference for the 1964 recommendation for the flu vaccine came from citation 1. Here’s a link (http://www.nature.com/nm/journal/v20/n9/full/nm0914-970.html), but the full text is not available, so I’ll copy and paste that section:

      “With the ACIP’s decision, Tdap became the second vaccine recommended for routine administration to pregnant women in the US. The first was the influenza vaccine back in 1964. “In the 1960s it was routine for pregnant women to get the flu vaccine,” says Janet Englund, an expert in pediatric infectious diseases at the University of Washington in Seattle.”

      Your point about long-term safety studies is fair, and it was certainly considered by ACIP when they made the Tdap recommendation for pregnant women. They did, however, have data on safety from women who received the Tdap vaccine before they knew they were pregnant. There is also a significant amount of safety data from other inactivated vaccines that have been given in pregnancy for some time, including flu and the tetanus vaccine (also included in Tdap), which is routinely given in developing countries to reduce morbidity and mortality from tetanus in pregnant women and their babies. Here is one review of what we know about safety of immunization in pregnancy:
      http://www.ncbi.nlm.nih.gov/pubmed/25285883

      Finally, remember that this recommendation was made in the midst of a pertussis epidemic that was – and still is – killing young infants. A vaccine, as with any medicine, comes with some risk, and it’s true that the recommendation for Tdap in pregnancy was made before we were certain what those risks might be. However, there is also a known and very devastating risk of the disease to young infants. The studies that I describe here are providing really solid data that Tdap in pregnancy is safe, and you can be sure that there will be more studies and surveillance data coming to ensure that this is indeed a good strategy for protecting infants from pertussis. I’ll be honest – as someone who will soon have a newborn in my care, pertussis absolutely terrifies me. After reading through these studies, I feel confident in my choice to receive the vaccine, and I’m grateful that it was available to me and other pregnant women.

      Like

      December 10, 2014
  10. I wish I had known this when I was pregnant! I had the booster about a year or two before becoming pregnant so I didn’t think I needed the vaccine – I made everyone around me get it though. Luckily my son is now 19 months and has had all his shots. Whooping cough is no joke – my little sister had it and almost died (luckily she had had the first dose of the vaccine so doctors think thats why she was able to beat it).

    Anyway, if we have another, I’ll DEFINITELY get the vaccine as recommended. Thanks for the info!

    Like

    December 10, 2014
  11. Reblogged this on Conceptionally challenged and commented:
    Great article about how the flu and Tdap vaccinations during pregnancy protect your baby before she can be vaccinated herself.

    SB just got her first DTap shot today (and the rest of the 2 months collection), making her more tired and crabby than normally, but for flu she still relies on protection through me (and herd immunity).

    Like

    December 10, 2014
    • maggie #

      Our pediatrician recommend a dose of Tylenol one hour before the appointment to reduce the reaction to the shots. I don’t know if there is any data to support this, but it sure worked well for us.

      Like

      December 11, 2014
      • b #

        My family doctor said that it was better to avoid any medication around vaccination appointments, especially just in case doses, because he had seen a study that said taking Tylenol etc unnecessarily meant that the vaccines were less effective.

        Like

        December 12, 2014
        • maggie #

          Alice – this sounds like a good topic for a future researched post 🙂

          Like

          December 15, 2014
          • Yes! I think I used to know the answer to this question, but now I’m not sure. I’ll check and see if I can find some data on it.

            Like

            December 15, 2014
  12. Lori #

    Thank you, Alice! Great post!

    Like

    December 10, 2014
  13. Alice, congratulations on your pregnancy and in another week or so your wait will come to an end. You have shared an important bit about pregnancy vaccination. All we worry about at that time is baby weight (and so I was on Fragmin for 8 weeks) or other health tests. Besides, in India, Progesterone shot has become like a cough syrup. Be it your first or a low risk pregnancy, one is put on pregnancy supporters for abso no reason. But, the forget about some serious issues such as the ones highlighted in your piece. Thanks for this informative one!

    Like

    December 10, 2014
  14. Roxanne Henderson #

    I would have gotten this had I known. My OB didn’t mention it and I thought I was up to date since I had one right after my daughter was born 2 years ago. I wish I would have known. I’m currently at children’s hospital with my 14 day old son who has rsv. I am now not allowing him to leave the house until vaccinated. This is bad, but Pertussis would be so much worse. Is there any data about how effective the vaccine is after just the first booster at 2 months?

    Like

    December 11, 2014
    • I’m so sorry that your OB didn’t encourage you to get the vaccine. It is a new recommendation and is probably taking some time for that info to get out there, but still – that’s discouraging! And I’m so sorry that your son has RSV – that’s really scary as well. There is actually an RSV vaccine in development for pregnant women that would help to protect infants as well.

      Your question about baby’s immune response to infant immunizations is excellent, and it’s one of the concerns about depending on mom’s antibodies to protect the infant – that the presence of maternal antibodies in the baby might blunt the baby’s immune response to his/her own vaccines. There’s some evidence that this does happen with Tdap in pregnancy, but it’s pretty minor. In the Munoz paper, they measured baby’s antibodies to 4 pertussis toxins at birth, 2 months, 7 months, and 13 months. At 2 months, before baby’s first vaccine, the babies whose mothers were vaccinated in pregnancy still had higher antibody levels than the unvaccinated ones. At 7 months, 1 of the 4 pertussis proteins was a little lower in the vaccinated group (but the other 3 weren’t different) – but both groups did still have a robust immune response to the vaccine. And by 13 months, they were all the same. We need more research on this, but it is looking like there may be a small effect but by the entire series of DTaP is completed, there is no difference. If there’s a small tradeoff there, then I think I’d still choose greater protection for my newborn, since a baby’s ability to survive pertussis is going to be much greater at 7 months vs. 1 month.

      More from the Munoz paper:
      “Importantly, although infants born to mothers immunized with
      Tdap during pregnancy did manifest lower pertussis
      antibody concentrations to filamentous hemagglutinin following receipt of the third dose of DTaP vaccine, the reduction
      was modest (48.3%) and disappeared following receipt of the
      fourth dose ofDTaP, suggesting that priming and memory immune
      responses remained unaltered. Although the presence
      of maternal antibodies could result in a decreased response to
      active immunization in infants,22 maternal pertussis antibodies
      have not been shown to interfere with immunizationwith
      acellular pertussis vaccines in young infants.4,23 A recent observational study of 16Tdap-immunized pregnantwomenalso
      found only modest reductions ininfant pertussis antibody levels
      following the third dose of DTaP vaccine.24”

      Like

      December 11, 2014
  15. I got vaccinated each pregnancy. I knew that regardless of whether it gave my child any sort of immunity, most infants get pertussis from their primary caregiver. And that I would never forgive myself if I made my baby sick.

    Liked by 1 person

    December 11, 2014
  16. Thanks for the information – as always thoroughly researched and trustworthy. I really appreciate it.
    I (finally) got pregnant myself. I’m switching from an OB to a birthing center and was worried that the birthing center wouldn’t offer the tDap, so I got it early in the 2nd trimester. I’m now sorry I did as no one in the OB office thought the timing mattered, so they were happy to give it early. I wonder if I should get it again at a more optimal time.

    Like

    December 11, 2014
    • Yay, Holly! Congrats on the pregnancy! I’m so glad for you.

      I wish I knew the answer to your question about 2nd trimester vaccination. Unfortunately, the studies on antibody response kinetics that I found (linked in the post – #7 and 8) only looked 4 weeks out. There wasn’t a decline in antibody response between 2 and 4 weeks post-vaccine (it looks like a plateau), which is encouraging for your case, but I don’t know how long your antibody levels might remain elevated. And I’m not sure if anyone knows if it would be advisable to be vaccinated twice in the same pregnancy. I’m sorry that I can’t be of more help!

      Like

      December 11, 2014
      • Holly #

        Thank you!

        Like

        December 16, 2014
  17. E #

    I am interested to hear your thoughts on this study: http://www.ncbi.nlm.nih.gov/pubmed/22727350

    Thanks!

    Like

    March 5, 2015
    • The conclusion of this study is this: “During a time when Tdap was not routinely recommended in pregnancy, review of reports to VAERS in pregnant women after Tdap did not identify any concerning patterns in maternal, infant, or fetal outcomes.”

      The important thing to understand about VAERS is that VAERS reports are not evidence of a causal relationship between the vaccine and an outcome. For example, this study found that 16.7% of reports were for spontaneous abortion, but the normal incidence of miscarriage in the U.S. is 15-20%. That these women received the TDaP vaccine and ended up miscarried was most likely a coincidence. This kind of study is a really important way of monitoring safety, and when the authors compared rates of adverse outcomes between women reporting to VAERS and in the general population, they saw no indicator that TDaP was causing any problems in moms or babies. Does that make sense?

      Like

      March 5, 2015
  18. E #

    And also this study: http://hospitals.unm.edu/mds/unmch/research/documents/pertussis.pdf

    I’m not trying to be contrary. I’m honestly just weighing the data at this point. It’s hard when there’s so much conflicting research out there. Thanks so much.

    Like

    March 5, 2015
    • This study supports the idea of immunizing women for pertussis during pregnancy, although it doesn’t specifically test it. The conclusion from this study:

      “75% of infants were born with pertussis antibody levels lower than
      the modest levels associated with potential protection. Despite
      effective antibody transfer, nearly 90% of infants were predicted to
      have little antibody by 6 weeks. Maternal immunization before or
      during pregnancy might simulate previous pertussis infection and
      help protect infants through the first months of life.
      ” [emphasis mine – the research described in my post also supports this.]

      This study measured pertussis antibodies in mothers and infants at birth. Mothers in this study had not recently received Tdap, and although babies had some pertussis antibodies (indicating that they did cross the placenta), levels were very low. This is exactly why immunization during pregnancy helps – it stimulates an immune response in mom, and then those antibodies get passed to the baby.

      I appreciate that you’re looking at this question so closely! The research on this issue is actually really solid so far in support of immunizing moms with Tdap during pregnancy – it isn’t conflicting. (If it’s presented to you that way, I have a feeling that you’re not looking at the best sources of information.) This is a new area though, and we definitely want to see more research, but in the meantime, vaccination in pregnancy looks very promising (and pertussis in infants is terrifying!).

      Like

      March 5, 2015
  19. Aarti #

    Hello Alice,
    I am 35 weeks and have this on my to do list. Would you still recommend it, for this summer baby? I am considering this. On the other hand, my 3 year old son attends a preschool that doesn’t require vaccines (!), and I haven’t observed teachers modeling the best hygiene there…

    Like

    May 4, 2015
    • Yes, absolutely. It is recommended regardless of season. Hope everything goes well with the new baby!

      Like

      May 4, 2015
    • Colleen #

      I had Whooping Cough in August 2012. It can definitely hit in the summer.

      Like

      September 3, 2015
  20. b #

    http://www.forbes.com/sites/tarahaelle/2015/05/11/pertussis-vaccine-remains-best-way-to-prevent-whooping-cough-especially-for-babies/ -> just released, and gives a good explanation of why the recommendation is Tdap for every pregnancy, even if your last booster was the year before.

    Like

    May 11, 2015
    • Thanks, b! Great article. Tara Haelle is the best for keeping up with vaccine news:)

      Like

      May 11, 2015
  21. Bronwyn Leslie #

    I read the Munoz study with 33 subjects ( I believe it is the same DTaP in pregnancy or postpartum study) 21% of participants had a serious adverse event. Researchers conveniently decided they had nothing to do with the vaccine but offer no explanation. What about the increased rate if miscarriage and still birth associated with this vaccine? Isn’t an alive baby better than a dead one?

    Like

    August 13, 2015
    • See Table 3 of the paper. The researchers describe these adverse events – but remember, these are any complication seen in the mother or the baby, and there is no evidence that they are related to the vaccine. Some examples – pelvic fracture from a motor vehicle crash, preterm contractions 33 days after receiving the vaccine, acute appendicitis 19 days after delivery, dehydration due to oral herpes simplex virus…. etc. You get the picture. They tracked these to see if anything popped up, but there really weren’t any red flags. This study really wasn’t designed to be able to detect rare adverse events, though – you need much bigger treatment and control groups to see that. This is why those much larger studies by Donegan et al. and Kharbanda et al. are so important, and they found that the vaccine was safe for both mother and fetus. In a study of 20,000 women, Donegan found no increased risk in stillbirth. (This vaccine is given in the third trimester, so if it endangered the fetus, this would be stillbirth, not miscarriage.) Every indication is that the vaccine is safe for use in pregnancy, whereas pertussis in a newborn can be deadly.

      Like

      August 13, 2015
  22. Jill #

    Hello! I only find studies pertaining to the pregnancy and newborn safety track record. Very little is given about longer term development and health. Can you help me with this gap?

    Like

    September 9, 2015
  23. Dana #

    This is concerning to me. Can you speak to this?
    http://www.ncbi.nlm.nih.gov/pubmed/23023030

    Like

    October 23, 2015
    • There are lots of concerns about this study that make me question it’s validity. First of all, I’m concerned that it was conducted by an “independent computer scientist.” The doesn’t have any background in immunology, infectious diseases, or epidemiology. He’s just a guy with a computer, and a little digging shows that he has published lots of anti-vax articles. So, I’m skeptical from the start.

      There’s also a big problem with using VAERS as a data source. It is an important part of vaccine safety surveillance, but it is an early warning system, and any pattern that might appear in VAERS really needs to be studied more rigorously through more systematic data source. Anyone can report an adverse event to VAERS, and a report doesn’t mean that the adverse event was caused by a vaccine. Heightened awareness or concern about a vaccine – or just more people receiving it – as in the swine flu season could certainly skew reports to VAERS.

      These are just a couple of concerns that jump out at me from the abstract of the paper, but I didn’t read it. Here’s a detailed analysis from someone who did: http://scienceblogs.com/insolence/2012/11/28/h1n1-vaccine-and-miscarriages-more-antivaccine-fear-mongering-about-flu-vaccines/

      Meanwhile, multiple studies that are MUCH better designed have shown that not only is the flu vaccine safe in pregnancy but it can actually prevent miscarriage by preventing the flu. As someone who lost several pregnancies, you can bet that I’d choose the flu vaccine every time.
      http://www.nejm.org/doi/full/10.1056/NEJMoa1207210
      http://www.ncbi.nlm.nih.gov/pubmed/23635613
      http://www.ncbi.nlm.nih.gov/pubmed/23635613

      I hope this helps!
      http://www.ncbi.nlm.nih.gov/pubmed/26238723

      Like

      October 23, 2015
  24. CLC #

    I despise how politicized vaccination has become. It’s no longer about what is right for the patient. It’s now about defending one’s position to the point of not properly testing for safety or ignoring facts. I don’t know who to trust anymore.

    How can it be safe and effective for the mother to get such vaccinations so often that are supposed to last 10 years? What if she gets pregnant 5 times in a row with each pregnancy within a year of each other? How is that safe? Has that even been tested? Just because a bunch of anti-vaxer Californians caused their babies to die, we as the mothers and delicate unborns have to pay the price for their stupidity. And the government just starts handing out vaccinations galore to mothers without testing when the FDA isn’t even sure if it’s safe at all for pregnant women to take?
    That’s as bad as the anti-vaxers!

    Like

    March 3, 2016

Trackbacks & Pingbacks

  1. 5 Evidence-Based Tips for Your Baby’s First Shots | Science of Mom
  2. Having a blog does not make you a health expert, so stop it!  | Learning Parenthood
  3. Resources for an Evidence-Based Pregnancy | The Science of Mom
  4. Not sure I want to get tdap shot in third tri; what are you doing? - Page 6 - BabyandBump

Comments are closed.

%d bloggers like this: