Immunisation and pregnancy with Dr Kerrie Wiley

Welcome to the Australian Prescriber Podcast. Australian Prescriber. Independent, peer reviewed and free.

I'm Dr Janine Rowse, your host for this episode, and it's a pleasure to be speaking to Dr Kerrie Wiley today about immunisation in pregnancy. Kerrie Wiley is a research fellow at the University of Sydney. She has an extensive background in research into the social and behavioural aspects of vaccination uptake particularly in pregnancy. She writes about this topic in the August edition of the Australian Prescriber. Dr Wiley, welcome to the program.

Thank you.

Vaccination in recent times has become a highly contentious issue with a lot of misinformation and safety concerns which has unfortunately affected childhood immunisation rates in some areas of Australia. Have these same issues been identified as affecting vaccination rates during pregnancy?

This information about immunisation in pregnancy isn't really the issue. With pregnancy it's more about information overload. So in the studies that have been done looking at women's attitudes to pregnancy immunisation, many women talk about the information overload and that when their provider makes vaccinations a priority by explicitly making a recommendation, they're far more likely to have the vaccine, especially if the vaccine is then available right there and then at the clinic. What we have done is that women who have chosen not to have the vaccine quite often cite safety concerns particularly first-time mums. So it's often helpful if the recommendations are accompanied by some reassuring information about how the vaccines are safe to be had while you’re pregnant and perhaps even I’d have a bit of a chat about what kinds of reactions you might see, like for example injection site reactions and this sort of thing.

So it that really shows how important the healthcare provider is in the situation.

Totally. A healthcare provider is integral in vaccination uptake in pregnancy.

Kerrie, in your article you mentioned the two vaccinations that should routinely be given during pregnancy – the pertussis or whooping cough vaccination and influenza. Pertussis or whooping cough infection in infants can have devastating consequences and that's gathered absurd bit of media attention in the last few years. Could you explain to us how vaccinating the pregnant mother can mitigate against this?

Well when mum’s immunised particularly in the last trimester all those wonderful antibodies that her body produces cross the placenta and provide the baby with protection so when that baby's born that baby is born already primed with mum’s antibodies against whooping cough. And it's enough for the first few weeks of life to give that baby protection until he or she is old enough to have their own first set of vaccines under the childhood program.

And correct me if I'm wrong but that first few weeks would be when the infant is most vulnerable otherwise because they're not protected by their own immunisations yet but also because they are quite young and so it seems to me that this really is a golden window of opportunity to protect the infant.

Yeah absolutely, the whole aim of this is to protect the baby and also that I mean the added extra is that mum gets protected as well. But the majority of the really really severe cases of vaccine and particularly the deaths I've seen in these very very first few weeks of life.

Now that we know about the vaccinations that routinely should be given during pregnancy – the pertussis and influenza – can you tell us about what vaccinations should not be given during pregnancy?

So pretty much any of the live vaccines are contraindicated during pregnancy, so things like the BCG vaccine, measles-mumps-rubella, rotavirus, varicella, in most cases the risk is hypothetical, it's just that there's not really a whole lot of data to prove that it's safe and if in doubt the Australian Immunisation Handbook has some very detailed information about what's contraindicated and why, and what to do if it's inadvertently administered, and it's all available online.

That sounds really useful and very important for healthcare providers to be aware of. I always really enjoy in clinical practice that the consultation where a woman comes in planning a pregnancy – such a wonderful opportunity to optimise the situation. What can women who are planning a pregnancy do?

Oh it's actually quite good because those vaccines that are contraindicated during pregnancy are obviously quite safe to take before you're pregnant so it would be quite good to assess maybe the need for things like measles-mumps-rubella or varicella, you know, do they have immunity to that or do they need the vaccines upfront? And part of that assessment could also be looking at if there's any overseas travel foreseen during the pregnancy, for example, to a place that might require a TB shot or Japanese encephalitis, for example.

Many new parents insist on a no vaccine no visit policy with any visitors, again quite controversial, in order to protect their newborn. How does this, I suppose, cocooning compare to having the whooping cough vaccination in the third trimester pregnancy?

From the parents’ perspective you can kind of understand. It's totally understandable that they want to really do everything they can to protect their baby from whooping cough which is why no vaccine no visit I think has really taken off. I think what parents need to probably be made aware of is that no vaccine no visit is an unofficial extension of the cocooning strategy recommendation from a few years ago. The official recommendation around cocooning was that close and frequent household contact like parents and siblings and possibly grandparents if they're around a lot of the time, that those close and frequent contacts be vaccinated to try and stop them giving whooping cough to the little baby. It didn't mean that everyone who sets foot through the door needed to be vaccinated. Recent studies show that if mums are vaccinated during pregnancy, that approach is around 90% effective in preventing severe whooping cough in their newborn baby.

If a patient does miss the recommended timing for the pertussis vaccination, which is recommended to be between 28 and 32 weeks gestation, what should their healthcare provider do? Is there a role for vaccinating at a later gestation or have we missed the boat?

The optimal time, the optimally recommended time is 28 to 32 weeks but it can be given anytime during the third trimester right up to delivery. If mum hasn't been vaccinated by the time she does deliver, it is a good idea for her to have the vaccine as soon as possible afterwards, so that would slide in under the cocooning strategy if you like. Research has shown that, where the source of whooping cough infection in a little baby is identified, it's quite often the mother. We did a big systematic review a few years ago that found about 40% of the time where they could tell who gave the baby whooping cough it was their mum and in another 16% on top of that was dad.

The mother needs to be vaccinated with each pregnancy doesn't she? It's the pregnancy-specific vaccination to protect that unborn child isn't it?

Yeah absolutely, for each pregnancy for mum, but dad or siblings it's not. It's with the normal recommendation for that age group. It doesn't have to be for every pregnancy. That's a question we hear quite often.

That's really important for families and grandparents are supposed to be aware of, otherwise it might be over vaccinating grandparents with a lot of grandchildren born in the one year. Can you tell us a bit about the influenza vaccination in pregnancy? It seems to me that this receives less public awareness than the pertussis vaccination. Is the influenza vaccination primarily to protect the pregnant mother or the unborn baby?

Yeah it's really interesting. Part of the research that we've done is looking at why there seems to be this difference in perception. So to answer your question, yes, influenza is to protect both mum and the baby, to protect mum during pregnancy and to protect baby for the first few months of life. So this research that I was talking about, this big study we did, showed that many women just weren't aware that flu, if you get flu while you're pregnant, it can be really devastating and it carries an increased risk of complications, but especially for women who are in their third trimester or if mum has a pre-existing condition like asthma or diabetes. But women just were really not aware of this.

Really interesting that you're reframing it as how we can protect the baby is much more effective. It seems that vaccination requirements in pregnancy and in general change frequently. What's the best way that healthcare providers can remain abreast of current recommendations?

Oh there’s a couple of ways you can do it and the Immunise Australia website which is www.immunise.health.gov.au has a professionals tab and if you click the clinical updates section there's updated information available there. We've also got the National Centre for Immunisation Research and Surveillance. Their website is www.ncirs.edu.au. They also have updates and a provider resources tab. They've got all sorts of really cool stuff. There are lots of fact sheets and things. NCIRS also have the Australian Immunisation [Professionals] Network which is a forum. It's like an email forum you can sign up to with over 900 other immunisation providers subscribed at the moment.

As I've already discussed pregnancy can be a really overwhelming time with so much competing information to be taken in by patients – dietary recommendations, tighter management of pre-existing medical conditions, and practical and financial planning for the inevitable arrival of a small human. We can see how important vaccination is during pregnancy. It really is a window of opportunity to protect the infant. From your extensive research in the fields what would be the most important take-home message for healthcare providers?

So if you tell them it's recommended, you reassure them that there's lots of data to show it's safe and it's effective, it will make a huge difference. And if you can on top of that find a way to make it available then and there for them, it'll help even more.

That's fantastic. So I suppose having it in the forefront of our mind as healthcare providers means it's in the forefront of the patient's mind as well?

Absolutely.

That's unfortunately all we've got time for this episode. Thank you so much for joining us today Kerrie.

Thank you so much for having me.

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Kerrie Wiley's full article is available online at www.nps.org.au/australian-prescriber and, like our whole journal, it's free. Subscribe to get the latest Australian Prescriber delivered straight to your email inbox and follow us on twitter @AustPrescriber to get the latest updates. The views of the hosts and guests on the podcasts are their own and may not represent Australian prescriber or NPS MedicineWise. I'm Janine Rowse and thanks for joining us on the Australian Prescriber Podcast.