Why we vaccinate for whooping cough during pregnancysteemCreated with Sketch.

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The majority of my academic work looks at the acceptance of the Tdap (tetanus – diphtheria – acellular pertussis) vaccination that aims to prevent deaths due to the spread of pertussis (whooping cough) to babies under 3 months of age.

Often, I try to keep my vaccination posts ‘light’ on the vaccinology and more focused on the psychology of vaccination, as this is my area of expertise. However, seeing as there are many misconceptions about this particular vaccine online (written by people that seem to have little concern when it comes to straying outside of their area of expertise) and it’s the vaccine that much of my work is pinned on, I thought I’d make an exception here. Title image credit: Max pixel

Why did the UK decided to vaccinate pregnant women with the Tdap vaccine

All pregnant women in the UK are recommended to take at least one vaccination during pregnancy. Since 2009, if it is flu season (Late September – Early April) women are offered the seasonal influenza vaccine, since 2012, all year round women are offered the Tdap vaccine. The reasoning is similar in both cases:

  1. The vaccines protects the mother during a period where their immunity system is in constant flux1

  2. If the mother gets ill during pregnancy this can cause a teratogenic effect (a teratogen is an agent or factor which can cause birth defects) to the developing foetus. 2,3

  3. Vaccinating during pregnancy passes on immunity, through the placenta, to the newborn child. Protecting them for the critical first few months of life, until they can receive their own vaccinations.4

The spread of pertussis in the UK during early 2012 ultimately led to the introduction of the pertussis immunisation during pregnancy program. As can be seen below there was a sudden 10x increase in cases compared to the ten year before that took the health system a little by surprise.

Source of data: Public Health England Archive

Worryingly, many of these cases were babies under three months of age.

Pertussis is a horrifying disease for a health adult to get, but to see a baby go through it is particularly heart wrenching. The bacterial infection starts off with symptoms similar to a cold, however, it later develops to cause intense bouts of coughing (known as paroxysms). Sharp intake of breath after coughing creates the characteristic ‘whoop’ noise (hence the name whooping cough). This coughing is often hard enough to induce vomiting, gagging and gasping for air, in severe cases these symptoms can prove fatal 5.

This was sadly the case for 14 babies in early 2012. Later that year the joint committee on vaccination and immunisation (JCVI) made the decision to implement the pertussis immunization program for pregnant women as an attempt to prevent further deaths 6. Initially this program was a temporary measure (due to cost-effective reasoning) however since rates of pertussis have remained high and a further 18 babies have died between 2013 and 2016 7 the program has remained in place.

Preventing the transmission of pertussis

Preventing the transmission of pertussis is no easy task. It is recommended that babies receive their vaccine containing the pertussis immunisation (6-in-1 Diphteria, Tetanus, Pertussis, Polio and Hib 8) at 2, 3 and 4 months of age. This slight delay is due to two main reasons,

  1. Newborn babies’ immune systems do not respond well before 2 months so the vaccine is less effective if it is deliver directly after birth.

  2. The vaccination does not offer immediate protection; it takes several days (and several doses) for a high level of protection to be developed.

Unlike with measles, neither pertussis infection or immunisation provides lifelong immunity to the disease9. Luckily, while still deeply unpleasant for child older than one or two years old, pertussis is rarely life threatening when contracted. This does, however, mean that people rarely top up there pertussis immunity, and as such it is often freely circulating within the population, preventing general community immunity form offering a high level of protection.

For a while some countries (e.g. Australia and Germany) attempted to interrupt pertussis transmission through a process known as cocooning. This strategy involves all adults and children that that are likely to be around a newborn being vaccinated in an attempt to surround the child with a ring of immunity10. While effective, ultimately vaccination during pregnancy has proven the optimal stratagem due to its higher effectiveness at a lower cost.

Safety and efficacy of vaccinating for pertussis during pregnancy

Pregnant women often shown high levels of caution towards medical interventions recommended during pregnancy. And rightfully so! Events such as the thalidomide tragedy cemented the risk of teratogenic effects related to medications in the minds of many parents.

The nature of our psychology, however, is to take events like this and make rules of thumb or “truisms”. In this case, the truism for pregnancy is that it is risky to take medication during pregnancy. Therefore, with the vaccination during pregnancy the bar for safety has had to be higher than many other medical interventions otherwise mothers might not see it, accurately, as significantly less dangerous than the disease (see my previous post on vaccines being a victim of their own success for more on this topic).

The first step of safety has been the prolonged use of the Tdap vaccine to provide immunity for millions of children for decades now with minimum side-effect above the common symptoms such as a painful upper arm and mild flu like symptoms11.

Next due to previous use of the vaccine in control strategies such as cocooning, accidental immunisation of pregnant women (i.e. women receiving a vaccination while not yet knowing they were pregnant) has been a common occurrence. While concern exists for live vaccines such as the MMR being accidentally given during pregnancy12, similar concerns are unfounded with the Tdap due to the fact the components are acellular13.

Finally, a 2017 systematic review of 15 random control trials studied the safety and effectiveness of the vaccine on over 200 thousand women14. Though this the authors found that there is no evidence of increased risk of serious complications such as stillbirth, or preterm birth related to the administration of the vaccine during pregnancy. A further systematic review is currently being undertaken by Cochran15.

As for effectiveness, in July 2014 The Lancet indicated that babies born to vaccinated mother had high levels of protection against pertussis and a 91% reduction in risk of pertussis disease in the first week of life16. Studies in 2016 and 2017 also showed similar effectiveness7

Has the program been worth it?

In the UK infant deaths from disease happen so rarely that when they do they are often front page news. When dealing with such small numbers it can sometimes be hard to see whether a policy is making a difference. With an infection, it can be even harder. A while back, when cases of pertussis were low, we moved from the TDP vaccine to the Tdap, this new acellular version of the vaccine was less prone to causing side effects however, the trade-off was a shorter period of immunity. This is potentially why we are now seeing pertussis circulating in the adolescent population far more than we used to. These adolescents are subsequently passing it on to their younger siblings. Ideally, we would cocoon and vaccinate during pregnancy however, with a limited pot of money we can only do so much.

Basing my research around this vaccine has made me realise how complicated vaccine policy can be, and from talking to women making their decision about this vaccine I have to say I understand the conflict that they face. There is so much conflicting information out there and this program really hasn’t been running that long.

The only advice I can offer when asked about this vaccine is to trust in the NHS and Public Health England's recommendation. From working around the people in these organisation that make these vaccine decisions over the last three years I can attest that they really do care about the same thing you do.

We all want children to grow up healthy, happy and free from disease.

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About me:

My name is Richard, I blog under the name of @nonzerosum. I’m a PhD student at the London School of Hygiene and Tropical Medicine. I write mostly on Global Health, Effective Altruism and The Psychology of Vaccine Hesitancy. If you’d like to read more on these topics in the future follow me here on steemit or on twitter @RichClarkePsy.

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References:

[1] The BMJ: Safety of pertussis vaccination in pregnant women in UK: observational study
[2] Short, S. J., Lubach, G. R., Karasin, A. I., Olsen, C. W., Styner, M., Knickmeyer, R. C., ... & Coe, C. L. (2010). Maternal influenza infection during pregnancy impacts postnatal brain development in the rhesus monkey. Biological psychiatry, 67(10), 965-973.
[3] Brown, A. S., & Derkits, E. J. (2009). Prenatal infection and schizophrenia: a review of epidemiologic and translational studies. American Journal of Psychiatry, 167(3), 261-280.
[4] Esposito, S., Bosis, S., Morlacchi, L., Baggi, E., Sabatini, C., & Principi, N. (2012). Can infants be protected by means of maternal vaccination?. Clinical Microbiology and Infection, 18, 85-92.
[5] UK Gov: Pertussis: guidance, data and analysis
[6] JCVI Minutes June 2012
[7] The Oxford Vaccine Knowledge Project: Pertussis vaccine in pregnancy
[8] The Oxford Vaccine Knowledge Project: 6-in-1 vaccine
[9] Cherry, J. D. (2012). Epidemic pertussis in 2012—the resurgence of a vaccine-preventable disease. New England Journal of Medicine, 367(9), 785-787.
[10] Munoz, F., & Englund, J. (2011). Infant pertussis: is cocooning the answer?
[11] Hansen, J., Timbol, J., Lewis, N., Pool, V., Decker, M. D., Greenberg, D. P., & Klein, N. P. (2016). Safety of DTaP-IPV/Hib vaccine administered routinely to infants and toddlers. Vaccine, 34(35), 4172-4179.
[12] Public Health England: MMR (measles, mumps, rubella) vaccine: advice for pregnant women
[13] The NHS: Can I have vaccinations when I’m pregnant?
[14] Furuta, M., Sin, J., Ng, E. S., & Wang, K. (2017). Efficacy and safety of pertussis vaccination for pregnant women–a systematic review of randomised controlled trials and observational studies. BMC pregnancy and childbirth, 17(1), 390.
[15] Murthy, S., Godinho, M. A., Lakiang, T., Lewis, M. G. G., Lewis, L., & Nair, N. S. (2018). Efficacy and safety of pertussis vaccination in pregnancy to prevent whooping cough in early infancy. status and date: New, published in, (4).
[16] Amirthalingam, G., Andrews, N., Campbell, H., Ribeiro, S., Kara, E., Donegan, K., ... & Ramsay, M. (2014). Effectiveness of maternal pertussis vaccination in England: an observational study. The Lancet, 384(9953), 1521-1528.

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Do you know why pertussis cases went way up in 2012?

Nice article BTW!

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Hey, thanks! Yeah, it seems to have been a bit of a global resurgence that year. The diseases has a natural 4 year cycle and in 2012 it looks like the move, around a decade previously, to the safer acellular vaccine offers a shorter period of protection. This means that the disease was actively circulating in adolescents and being passed on to younger infants in the family. This is what I’ve heard for colleagues that do the epi on this one.

Here’s the incidence of pertussis per 100 000 of the pop in the US up until 2011. The cycle is clearer in this. . Source

Hello @nonzerosum,

Thank you for taking the time to address this topic. It is great to see the program proved to be successful (it was heart-breaking to read and picture babies undergoing such harsh symptoms, and dying from them).

Hopefully, people will realize that, health systems, such as the NHS, and others around the world do care about individual's well-being. And the development and achievement of such programs, like the one you discuss here, stand to demonstrate this.

All the best :)

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Hi @abigail-dantes, thank you for your comment. Yes, some of my work in the past has been to put together videos of babies with whooping cough. That was some of the most distressing work I’ve ever had to do, I dread to think what it would feel like to see it in real life.

I think people do. Despite being chronically underfunding, trust in the NHS still remains high and recently we even hit 95% vaccination for the MMR vaccine for the first time ever. This pregnancy vaccine is currently taken by around 75% of mothers, which is pretty great considering how new this process is.



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I think the public has trouble trusting for two reasons. The first is that there are clear cases where interventions clearly caused harm, sometimes due to incomplete information (say thalidomide) and sometimes due to malevolence on the part of drug companies. The second is that science is not always linear--recommendations on the best evidence today may be overturned in a few years. The general public doesn't have a good understanding of the scientific method and the media often don't help. Your posts are far more level headed and evidence-based than what many people will see in a 20 second blurb or a two line click-bait headline.

Proud member of #steemitbloggers @steemitbloggers

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So, when it comes to trust I think you’re dead on, except for one aspect: it is never the responsibility of the public to ‘trust’. This is something our team were playing around with in this paper (which we’ve managed to make open access so I should probably blog about it soon). If trust is lost, there is always something that we can do to make the system more ‘trust-worthy’. It’s like in teaching, there are no bad students only bad teachers. If my students aren’t understanding a topic that I’m talking about then it’s my responsibility to explain it in a different way so that they get it.

It’s not a perfect way to see the dynamic but at least it means that there is something that I can do to make the situation better (other than blaming people). In healthcare, if people have lost trust let’s find the reason why and work it improve it. E.g. Working closer with the media, or doing direct communication such as this.

Hey, thanks for your kind words, I will take your complement (something that I’m usually quite bad at)! However, I do have to say there is some incredible work being done around vaccine communication. E.g. the vaccine knowledge project and vaccine today it can just be hard to reach people sometimes.

I had whooping cough as a child--everyone in my family did. We lived in a rural area and didn't have easy access to medical care. I thought that having the infection conferred lifetime immunity. I'm sure a lot of people of my generation believe the same. We really do have to get the word out that this is not so. Thanks.

By the way, when we moved to NYC and registered in school, first thing the nurse did was make sure we were caught up on all our vaccinations. That was not a fun day:)

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Yes, it becomes less of a health issue once an infant grows up but it’s a good idea to top up immunity if you’re likely to be around infants and whooping cough is currently circulating in your community (i.e. community). Also some people assume immunity is passed on as long as they continue breastfeeding, while this is partly true this is not ideal, far better protection is gained by vaccination during pregnancy.

Ha, yeah I can imagine that’s a lot of jabbing!

Whooping cough is truly a horrible disease and we should due whatever we can to prevent its spread. Always get your booster!

Great article. I'm from the Seattle area of US and unfortunately we've experienced the loss of a baby in our family due whooping cough

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Hi @shawnsporter, Thank you for your comment. I’m so sorry to hear this, that must have been a really tough experience. Some of the families that I’ve talked who have gone through a similar experience have said this Facebook page has been a great source of comfort over the last few years: Light for Riley.

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Thx Sir... you've got a new follower here on Steemit!

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Hey, thanks. I appreciate it! Likewise

Awesome post as usual @nonzerosum.

My only concern is that you are preaching to the choir.

This community is very self selected. Would be good to get this out into some of the powerful facebook posts that are anti-vaccine, etc.

Many with increasing users here it will help.

Have you had much feedback from the other side of the debate?

Edit: besides some of the comments below.

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Yes, to a degree there I think you’re right. The stemsteem community is going to align quite well, however I also tags with #health #vaccine which are sometimes a great deal less evidence based. I’m tempted to start using the #naturalmedicine tag however I’m cautious of being antagonistic with my posts. As you can see for the comment opposed to vaccination below, the conversation rarely goes well.

I think the top comment on this previous post is what I’m aiming for. If you ever see a conversation that goes like this please do upvote it, it would be great to see discourse like this incentivised more.

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PS. I've read into that comment you mentioned and it is very thoughtful conversation! Thanks for sharing with me! Cheers!

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Thanks for your reply.

I think your idea of #naturalmedicine is a good one. Perhaps then you will start reaching a wider audience. Polarisation of ideas is always hard, because people stop thinking (on all topics). Being critical is the key!

Agreed with you and thanks for sharing the link.

I still think a big picture Rotary in Africa post would be cool... someday I will give it a go if I have time. Keep up the great work!

Such a wild data trend...
Thanks for mentioning the "cocooning", it's the first time I heard about it.

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Yes, it’s a good term to know. It's like the inverse of ring vaccination. It's probably how we need to start talking about seasonal influenza. E.g. if you’re going to visit your grandparents this christmass make sure you get the flu shot.

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Never been vaccinated, never been sick.

They use fear and government propaganda to mislead the population into thinking vaccines are safe in order to control the people and make themselves billions in the process.

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Never been vaccinated, never been sick

You’ve been luck to experience one of the amazing benefits of living in the UK. Our vaccination program is so effective that it prevents the spread of the disease to such a degree that those that are not vaccinated (or can’t be vaccinated, as is the case for those with a compromised immune system) are shielded.


Also, full disclosure, there’s a good chance I’m going to steal your phrase here for a blog post on this topic in the future

I know you think you’re helping by sharing the information below but most of this really isn’t viable information to inform how we structure our disease prevention programs. The emotional content here is high and that has a habit of drawing us in, but the narrative that is spun really doesn’t hold much water when you talk to the people involved in vaccine policy.

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You Just got Lucky Bro.

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Thanks for the misinformation propaganda.

Just hope your kids get close to mine.

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You're the one who has fallen for the misinformation propoganda if you believe vaccines don't do damage.

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Sorry brother, but arguing with anti-vaccine people is like arguing with flat-earthers. No matter how many actual scientific evidence your throw at them, they will keep denying it.

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I've presented evidence of vaccine damaged people. I'm not the one in denial.

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Biased youtube videos isn´t actual evidence.

Scientific method exists for a reason.

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Absoloutely. those vaccine ingredients are well worth keeping away from. What a lot of damage they've caused! Mercury, aluminium, aborted fetal cells, formaldehyde, to name but a few...oh my goodness why would you want to put these poisons into a healthy child.

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