Vaccinations to consider before, during, and after pregnancy

Clare Taylor: 0:15

Hello and welcome to ESWI Airborne. The hot topic today is vaccinating pregnant women. I am your host, Clare Taylor, and this is the place to be to meet the members of ESWI, the European Scientific Working Group on Influenza. Today, we are hearing from ESWI board member Dr George Kassianos, a truly pan-European man. George is a Cypriot, studied in Poland and in the UK and since 2020, George is a commander of the British Empire, CBE no less, appointed by Her Majesty the Queen of England to acknowledge his most distinguished career. George, welcome to ESWI Airborne.

Dr George Kassianos: 1:01

Thank you, Clare, very much. It's really very nice to be able to talk to you today about a very important subject in primary care.

It sure is a hot topic. I know that from my circle of acquaintance. But first can you tell us, George, what motivated you to train as a general practitioner?

Simple. During my medical studies and my hospital training that I followed at the Hammersmith and St Mary's hospitals in London, I wanted to specialise in every specialty I was working in. Once I saw what a family doctor does, I never looked back.

And one of the areas where you chose to specialise was immunisation and travel medicine, and I understand that you are a recognised authority and expert in this field. What started this interest?

Well, we have to go back to the 1970s. During the fourth year of my six-year studies in Łódź in Poland, where I studied with a scholarship from the International Union of Students, I led on a research on patients in the town's hospitals with the diagnosis of inflammatory liver disease. We were trying to identify the Bloomberg's antigen, or Australian antigen as we used to call it at the time. Later on it was infectious hepatitis and after that it was hepatitis B. When I started working as a GP in my practice in 1979, we didn't have contraindications to vaccinations and I asked my partners and our nurses and midwives, all of us to agree on what were at the time the contraindications to vaccinations because a number of children were actually left unvaccinated because of perceived contraindications by the advisor. I wrote that up on a page and a half of A4. Ten years later, so the first edition of my book on immunisation and travel health, and ten years after that, so the fourth edition of the book, and that's how it all started.

So that's how it started, from small beginnings to great things. I'll think of that the next time I write a list on a page of A4. But more recently, George, since March 2020, so since the pandemic started in Europe you have been appearing weekly on BBC Radio Berkshire answering questions on COVID-19 and influenza. Do you feel it's important for doctors to be public spokespersons?

Well, Clare, some scientists have the charisma of being able to explain simply to the population on the radio, on TV, issues around vaccines and immunisations. In my case, I'm a family doctor and advising patients as best as I can is what I do.

Okay, George, I'd love to get some advice from you right now about vaccination in pregnancy. Why should pregnant women receive any vaccines at all?

There are two good reasons why pregnant women should consider receiving appropriate vaccinations. First, they protect themselves from the infectious disease, which also helps them not to become the source of infection for their newborn babies. The second reason is to pass their own antibodies to the fetus via the placenta, so that the neonate has a degree of immunity in the early neonatal period.

And what are the vaccines that pregnant women should get?

Well, it's important to actually know that you need to start vaccinating well before a woman becomes pregnant and, of course, a family doctor or an obstetrician, when consulted by a woman planning pregnancy, should check the immunisation history. This may be vaccination or having had the infectious disease in the past. In certain circumstances, you may have to do serological testing.

And what is serological testing?

It's actually testing really in the blood to see if somebody has had an infection.

I think I understand, like if I've had the measles before, I don't need to take the vaccination for it. Is that right?

Indeed, and of course there are three vaccines that are important in pregnancy, and the first one, of course, before you fall pregnant, it's the MMR, is the mesosmanum serubella, the hepatitis B is another one, and also varicella, if one has not had chickenpox in the past. And these vaccines you have to think of well before a woman becomes pregnant.

Aren't two out of three of these vaccines live vaccines?

Yes, of course the MMR and varicella vaccines are live vaccines, but the viruses in these vaccines are attenuated, that is, they have lost entirely their ability to replicate, to multiply. All live vaccines should be avoided during pregnancy and one month before falling pregnant. That is very important.

Thanks for highlighting that. Are there any other vaccines to consider?

Yes, adolescents should also consider the human papillomavirus HPV vaccine and also the meningococcal vaccines MEN-B and MEN-ACWY. This will ensure they are fully vaccinated before they contemplate pregnancy. Also, those with anatomical absence of spleen as well as this splenic dysfunction should, in addition, receive the pneumococcal vaccine. During the flu season this seasonal influenza vaccine is very important.

Okay, so most of these are, in fact, all apart from the influenza should be taken before pregnancy, but what about a woman who is already pregnant? What vaccines could she consider then?

Well, there are three vaccines that are very important during pregnancy: the pertussis-containing vaccine, which is given in the UK from 16 to, ideally, 32 weeks. But if after 32 weeks we still give the vaccine. Transplacental antibody transfer from mom to baby is thought to be highest during the period between 20 and 32 weeks, and that is the best time to give the pertussis-containing vaccine. The second important vaccine now is, of course, covid-19 vaccine. And the third has always been very important is the seasonal influenza vaccine during the flu season for women already pregnant or women who become pregnant during the flu season. Pregnant women can receive rabies vaccination if required, for example for post-exposure prophylaxis.

It is though, there may be pregnant women who have received a vaccine before they knew they were pregnant, so, for example, the MMR. Is there a risk here to the fetus? Can you talk a bit about that?

Yes, here people worry specifically of congenital rubella syndrome in the newborn. Really, Clare, this is a very good question and it comes up quite frequently. Countries like the UK, Germany, the United States and others carry out active surveillance and none of the babies after inadvertent administration of the MMR have developed abnormalities compatible with congenital rubella syndrome. Further, there has been no increase in the risk of miscarriage or stillbirth in pregnant women who were susceptible, that is, they were non-immune when they were inadvertently vaccinated when compared to those protected by prior immunity. Basically, inadvertent MMR vaccination during pregnancy would not be a reason to recommend termination of pregnancy in the UK.

That's good to know, George, and can passive immunisation be used during pregnancy?

Right, that's a very good question, because sometimes we need to do that. We have limited data as regards to passive immunisation, that is, the administration to a pregnant woman of ready-made antibodies. As far as we know, there is no risk to the fetus from passive immunisation given to the mother when it is needed, such as immunoglobulin for measles, hepatitis A, hepatitis B, rabies, varicella, that's, chickenpox and tetanus, of course.

Let's now turn to women who are breastfeeding. Which vaccines are safe to receive for breastfeeding mothers?

Yes, breastfeeding mothers can receive most vaccines. Seasonal influenza and COVID-19 vaccines are very important as they reduce considerably the risk of the mother getting infected and in turn infecting the neonate. Breastfeeding mothers can receive live vaccines, such as the MMA, varicella, but also the intranasal live attenuated influenza vaccine, if the mother's age is within the licensed age of this vaccine. The yellow fever vaccine should be avoided during breastfeeding unless the mother is at a very high risk of infection. If mother is breastfeeding, but particularly if the breastfed baby is under the age of nine months, expert advice should be sought before considering yellow fever vaccination.

For the situation where a pregnant woman did not receive the pertussis-containing vaccine during her pregnancy. Can she receive this after the birth?

Well, yes, indeed, every effort should be made for the pertussis-containing vaccine to be given as early as possible in the postnatal period. If it was not given, of course, in pregnancy, it will protect the mother and prevent her from becoming a source of infection to her infant, but it does not provide direct protection to the baby. If mother is breastfeeding, then the infant may get some immunity, but it is not enough to replace the need for the infant to complete their own primary immunisation schedule. By the way, vaccinating those around the infant against influenza and pertussis can protect the neonate, and that is what we call cocooning. It is vital that all newborn babies are protected against pertussis, but also influenza and COVID, and the best way to do this is to vaccinate the mother during pregnancy. Listeners to this podcast that are pediatricians or family doctors know well the difficulties we have in making the diagnosis of pertussis in neonates. This is because many babies do not actually have that characteristic cough, the hope, but instead they just stop breathing or turn blue.

Which is a terribly frightening prospect for any mother and emphasises just how important vaccination is for the baby and for those caring for the baby. Now, George, I want to ask you about another vaccine, the HPV, which is usually given to adolescents, and would you see any problems or difficulties there if this coincided with a pregnancy?

Well, Clare, we have limited data on using the HPV vaccine during pregnancy because pregnant women were excluded from the vaccine trials. The HPV is an inactivated vaccine. It cannot replicate or cause infection. Nonetheless, as a matter of caution, in the UK the HPV vaccine is not advised in pregnancy. No specific concerns have been identified, so if a young woman finds out she is pregnant after she has started the course of HPV vaccine, we should counsel our patient and any further dose or doses should be scheduled after completion of pregnancy.

We are really chasing down every possible situation here today, including the situation where the pregnant mother is receiving immunosuppressive biologic therapy. What advice would you give them, George?

Now this is a very important question. Yes, it is rare, but it's important. Certain immunosuppressive medicines, such as the biological disease-modifying anti-rheumatic drugs, the BD-MARTS, may cross the placenta and be detectable in the infant. This is especially true if given during the third trimester. In these cases, vaccination of the newborn baby with live vaccines one should be delayed by six months. Two, the BCG vaccination, if indicated in the non-edal period, should be postponed until six months and three, in practice, such babies will not be able to receive the rotavirus vaccine. If there is any doubt as to whether an infant, due to receive a live attenenuated vaccine, may be immunosuppressed due to the mother's therapy, including exposure through breastfeeding, specialist advice should be sought, in my view.

Thanks for that, George. Another challenging situation is when the pregnant mother is infected with the hepatitis B virus. What action would you advise in this instance?

Well, my answer, Clare, here reflects the action we take here in the UK. A baby born to a hepatitis B infected mother will receive a monovalent hepatitis B vaccine dose soon after birth, usually in the hospital where the baby is born. Another dose is given by the GP at four weeks of age. The baby then receives the hepatitis B containing hexavalent vaccine at 8, 12, and 16 weeks. We then complete the schedule of vaccination with another dose of the monovalent hepatitis B vaccine at 12 months, followed by serotesting for hepatitis B surface antigen to see if the baby may be infected. Altogether here by the age of one year the baby receives six doses of the hepatitis B vaccine. But I must remind our listeners the scenario where the mother may not be infected but the newborn may be going to a household where a hepatitis B infected person lives. Such a neonate is at risk and in the UK this baby will receive a monovalent dose of hepatitis B vaccine before discharge from hospital and then the GP practice will continue the routine childhood vaccination, starting at eight weeks. Altogether, a baby under this scenario will receive four doses doses of the hepatitis B vaccine.

Okay, that's sound advice for any mothers with hepatitis B or household members where a new baby is coming into the household. Let's now turn to influenza prevention in pregnant women. Do pregnant women really need a flu vaccine, and when should they get it?

First, we must take into consideration the fact that pregnancy alters how the body handles infections such as flu. Influenza infection increases the risk for complications of pregnant women but also their babies, needing intensive care. The flu vaccine reduces the risk of a pregnant woman having serious complications from influenza infection, such as pneumonia, particularly in the later stages of pregnancy. The risk of miscarriage, premature birth, stillbirth, a common influenza symptom, that is, fever may be associated with neural tube defects and other adverse outcomes for the developing baby. What is important to know is that the pregnant mother passes antibodies against influenza to her fetus by the placenta and therefore protects the baby in the first months of life, when the neonated cannot have the flu vaccine because flu vaccines are not licensed for any babies under the age of six months. So the flu vaccine protects a mother and baby if given to the mother at any stage of pregnancy. Some women are not pregnant at the beginning of the influenza vaccination season, when we vaccinate most of our patients, but for pregnant during the flu season we must remember to still offer them the flu vaccine.

Well, there was not so much flu going around for the past influenza seasons during the pandemic. What are the conclusions that we can draw from this?

Pregnant women, just as anybody else, have learned the importance of medication measures to avoid infection, such as frequent hand washing very important good ventilation, keeping a good distance from others when meeting ideally meeting outdoors and, of course, wearing a well-fitting, high-quality mask in areas where other people are also circulating. The same mitigation measures work for COVID-19, influenza as well as other respiratory viruses. And, of course, pregnant women, like all of us, have learned the importance of vaccination.

But, George, there are still certainly many pregnant women I know some of them who are unsure as to what a COVID-19 infection would mean for them during their pregnancy and indeed whether they should get vaccinated. So if we could first take a look at the infection itself, how serious is COVID-19 during pregnancy?

As yet, we have not seen any real evidence of COVID-19 infection increasing the risk of miscarriage, and no evidence of further developmental problems. Yes, still pregnant women may become seriously unwell and need hospital treatment, especially if unvaccinated. Now let's look at COVID-19 infection. In one study, 47% of pregnant women that tested positive for COVID-19 were asymptomatic, but remain at higher risk of maternal morbidity and pre-eclampsia. This is asymptomatic women pregnant. Further, 27% had mild infection, 14% had a moderate and 8% severe infection. About 4% presented in a critical state and these patients were more likely to have raised BMI, comorbid conditions, especially pre-gestational diabetes, hypertension, and four pregnant women out of 1,219, unfortunately lost their lives to COVID-19. This infection is a serious infection, particularly during the latest stages of pregnancy.

These are indeed the most serious consequences to a minority, but nonetheless, at a time when none of us would want to gamble or take risks, can you tell us a bit more about the risk aspects during the late stages of pregnancy?

Yes, pregnant women with COVID-19 infection, compared to pregnant women without COVID-19 infection, experience more incidence of preeclampsia, aneclampsia, admissions to intensive care, mechanical ventilation, spontaneous or medically indicated preterm birth, myocardial infarction, venous thromboembolism, cesarean delivery, maternal mortality and increased perinatal morbidity and mortality index. In addition, a small number of neonates test positive for COVID-19, about 13% in one study.

Can a baby catch COVID-19 through breast milk, for example, if the mother is sick?

Well, in a study published in JAMA, that's the Journal of the American Medical Association, SARS-CoV-2 virus RNA was detected in the milk of one out of 18 breastfeeding mothers. The viral culture for that sample was negative, which suggests SARS-CoV-2 virus RNA does not represent replication-competent virus and therefore breast milk may not be a source of infection for that infant.

This is reassuring, of course, because of the many benefits of breastfeeding and also for breast milk provided through milk banks, that this is not a transmission path for COVID. So let's now turn again, or look again, at this issue of getting the COVID vaccine in pregnancy. My first question is whether we are giving pregnant women a live vaccine when vaccinating them in pregnancy.

Yes, the messenger RNA vaccines we use in the UK, that is, the BioNTech, Pfizer and Moderna are not live vaccines. The Oxford AstraZeneca vaccine contains a replication deficient Chimborzine adenovirus vector that encodes the SARS-CoV-2 spike glycoprotein that can neither replicate nor survive. In pregnant women the preferred vaccines in the UK are the messenger RNA vaccines because of more extensive experience we have of their use in pregnancy. In fact, more than 140,000 pregnant women have been vaccinated in the United States and over 80,000 in the UK, with no safety concerns identified.

Okay, so just under a quarter of a million pregnant women in that sample size. That is good news that there have been no adverse effects identified. How early in pregnancy can the COVID vaccine be given?

So far, we have found no evidence of an increased risk for early pregnancy loss after COVID-19 vaccination. Pregnancy outcomes following messenger RNA vaccination appear similar to comparator groups prior to the onset of COVID-19 pandemic. What's more, short-term reactions among pregnant and breastfeeding mothers are similar to those who are not pregnant or lactating.

And can you get the COVID vaccine at the same time as you go for the flu shot? Can these vaccines come together at the same time for a pregnant woman?

Yes, no safety concerns have been raised over administering the COVID vaccine alongside the influenza vaccine.

It's good to hear this directly from you, George, and I'd also like to know what's the official line, the official advice from the European Medicines Agency. Do they give any advice about vaccinating pregnant women?

Yeah, this is very important to know, actually, because we want to know what the EMEA says. Well, the EMEA task force looked at around 65,000 pregnancies at different stages and announced in January 2022 that they did not find any signs of an increased risk of pregnancy complications, miscarriages, preterm births or adverse effects on unborn babies following messenger RNA COVID vaccination.

So what are the benefits of a pregnant woman getting vaccinated against COVID?

Most of pregnant women who become seriously ill with COVID-19 are unvaccinated. Vaccination is the best way to protect mother and baby. Those with underlying clinical conditions are at even higher risk of suffering serious complications. In clinical trials, the messenger RNA vaccines have been found to be well-tolerated and effective in pregnancy. The vaccines might offer the unborn child some protection against COVID-19, as antibodies in response to the vaccine can be passed from mother to newborn during pregnancy and through breast milk after birth. Very important is to note that there is no current evidence of any serious side effects in pregnancy. The current evidence does not show an increased risk of miscarriage, stillbirth, congenital anomalies, birth complications following vaccinations against COVID-19. As a family doctor, my advice is that if a woman is trying to become pregnant or is now pregnant or breastfeeding or bottle feeding, she should make sure she gets fully vaccinated against COVID-19, but also against the other diseases we have already discussed in this podcast.

Well, folks, you heard it here first, the A to Z on vaccination and pregnancy from Dr George Kassianos. George, thank you so much for putting the record straight.

You're welcome, Clare, thank you.

Thanks also to our listeners, and until next time, stay safe.

Aida Bakri:

ESWI Airborne is brought to you by ESWI, the European Scientific Working Group on Influenza and other acute respiratory viruses. These episodes would not be possible without the team's efforts and we would like to extend special thanks to our ESWI secretariat, our technical and IT teams, our arts team and our host, Clare Taylor. The podcasts are recorded virtually and we thank our guests for their participation in this inspiring series. Talks are adapted to a global audience and are intended to be educational. For any specific medical questions you may have, these should be addressed to your local general practitioner. Many thanks to our sponsoring partners and thank you for listening.

Vaccinations to consider before, during, and after pregnancy

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