Ask the expert: Vaccinations in pregnancy and early childhood - £200 voucher to be won

[LibbyMumsnet]

Vaccinations can raise lots of questions, whether you’re expecting a baby or taking your child for their routine immunisations. With the NHS vaccination schedule changing this year, you may also have questions about what applies to you and your family.

We’ve invited Danielle Robinson, Lead Vaccination Nurse, and Emma Lormor, Senior Vaccination Nurse, from Northumbria Healthcare NHS Foundation Trust, to answer your questions about vaccinations in pregnancy and early childhood. Danielle and Emma will be posting answers throughout Feb/March.

Share your questions by 16 March for your chance to win a £200 VEX voucher (T&Cs apply).

About our experts:
Danielle Robinson is a Lead Vaccination Nurse with 25 years’ experience as a qualified nurse and has specialised in vaccinations for the past four years, supporting pregnant women, babies and young children.

Emma Lormor is a Senior Vaccination Nurse who supports the organisation and delivery of NHS vaccination programmes across a wide range of settings, including for pregnant women and young children.

You may also find Mumsnet’s vaccination reminders helpful for keeping track of which vaccinations are due and when.

Hi

My child has just turned 3 so is due his MMR booster soon and I understand that this will now contain the chicken pox vaccine as well so is now the MMRV booster. My child hasn’t had chicken pox or a previous dose of this vaccine so I just wanted to check whether he would get full immunity from having just the one dose as part of his vaccination schedule or whether he was actually running the risk of getting chicken pox as an adult when the immunity from this single dose faded. If this is the case is there any way to organise a single dose to act as his second dose? The private sources I have looked at only seem to offer a double dose.

Thank you!

Thanks to everyone who has submitted a question so far.

We’re pleased to announce that the winner of the prize draw is @Alwaystiredzzz 🎉

Danielle and Emma will be back over the next week or so to answer a few more questions.

My 3.5 yo missed her third MenB, should she still have it?

How safe is DTap? Have heard some horror stories...

Hello @Antihistamine62 - thank you for your question. You’re not overthinking this - it’s a really common and sensible question.

In short, yes, ibuprofen can be given for fever or discomfort after the measles, mumps, rubella and varicella (MMRV) vaccine, as long as the child does not have a chickenpox-type rash. The measles, mumps, rubella and varicella (MMRV) vaccine is a live vaccine, but that does not mean ibuprofen is unsafe.

After the measles, mumps, rubella and varicella (MMRV) vaccine, some children develop:

• A fever
• Occasionally a very mild rash (often just a few spots). This is a vaccine response, not true chickenpox.

If your child develops a high temperature following MMRV vaccination, you can give them paracetamol or ibuprofen. However, if they develop a chickenpox-like rash, which can be 3 to 4 weeks after they have received this vaccine, it is recommended that you do not give them ibuprofen because it might make the rash worse, and there is a risk of the spots becoming infected. This is something that has been a concern following natural chickenpox infection and is why it is recommended that you do not give ibuprofen to your child if they catch chickenpox naturally. As a precaution, we give the same advice for a chickenpox-like rash after vaccination. If your child does develop a post-vaccination rash following their MMRV vaccination, you can give them paracetamol and medications available from a pharmacy that you apply to their skin to relieve itching.

Our advice
Paracetamol (Calpol) is usually suggested first line (mainly because it’s simple and familiar).

Ibuprofen is also fine if:

• Your child is well hydrated
• There is no vesicular (blistering) rash
• There are no usual contraindications (e.g. asthma triggered by NSAIDs, dehydration, kidney issues)

Avoid ibuprofen if:

• The child develops a clear chickenpox-like rash (multiple fluid-filled blisters)
• There’s diagnostic uncertainty and it looks more like true chicken pox (varicella)
• The child is unwell, dehydrated, or has other standard reasons to avoid NSAIDs

For further information, you can take a look here: https://www.nhs.uk/vaccinations/why-vaccination-is-important-and-the-safest-way-to-protect-yourself/

Hi @Wsandy,

Thank you for your question. You might see something similar after the second varicella dose, but many children have fewer or no side effects the second time.

The vaccine your little one is likely to have had is the MMRV vaccine if they had it in January this year, protecting from measles, mumps, rubella and varicella (chickenpox) and therefore any side effects/reactions could have been caused by any of the components in the vaccine.

A rash following vaccination with MMRV vaccine may be related to either the measles or varicella/chickenpox component of the vaccine.

A measles-like rash/rash due to the measles component is most likely to occur about a week after immunisation, and last about 2 to 3 days.

A rash due to the varicella/chickenpox component usually occurs within one month of vaccination.

However, any rash is a sign the immune system is responding.

The first dose is more likely to cause a rash than the second, and if your little one did have a rash after the first, it doesn’t mean it will happen again. Reactions from second doses are much less likely because if the child made a good immune response (they made antibodies) to the first dose, these antibodies neutralise (clear) the vaccine virus in the second dose.

If a rash does appear after the second dose, it’s usually:

• Mild
• Short-lived
• Much less extensive than real chickenpox

You don’t usually need to do anything other than keep them comfortable. It is uncommon, but if the rash is widespread, blistering, or your child seems unwell, it’s sensible to check in with your GP.

Hi @CSweeting,

Thank you for your question and sharing your concerns with us. It’s understandable to have questions about vaccinations offered in pregnancy and your concerns are thoughtful, informed, and very reasonable.

You’re right about several things:

• The maternal RSV vaccine is relatively new compared with flu or whooping cough vaccines
• The main study included around 4,000 pregnant women. While this is smaller than the very large trials carried out for vaccines that have been used for many decades, it still provides strong evidence for use in pregnancy
• There are no direct human fertility studies, and limited paediatric data beyond infancy

Let’s look at those factors in turn and why it’s still been approved and recommended

1. Trial size in context
While 4,000 may sound small, in vaccine terms this is actually a standard and accepted pregnancy safety dataset

Crucially:

• There was no clear evidence that the vaccine caused any harm
• Although slightly more preterm births were seen in the study, there was no clear pattern or explanation to suggest the vaccine was the cause
• No increased risk has been found by ongoing real-world monitoring of the vaccine, which has now been administered to women in tens of thousands of pregnancies worldwide

2. Fertility concerns
You’re right: there are no dedicated human fertility trials, but this is also true for:

• Flu vaccines
• Whooping cough vaccines

Why this matters:

• There is no biological reason to suggest that the RSV vaccine could interfere with the body’s ability to become pregnant
• Extensive post-marketing data from other vaccines shows no fertility impact, even when this was a major concern initially
• Animal reproductive studies did not show harm
• This is why regulators, including European Medicines Agency, did not require fertility trials as a condition of approval.

3. Why there’s limited data in children aged 2–18
The reason is not safety concerns, it is because:

• The research has focused on those at highest risk of serious disease. RSV is most dangerous for babies, especially serious for babies under 6 months old who are at significantly higher risk of serious disease. By their first birthday at least half of children have experienced an RSV infection, and almost all will by the age of two.
• RSV can lead to bronchiolitis, causing breathing difficulties, feeding problems and often hospitalisation.
• The vaccine is designed to be given in pregnancy, so mum’s antibodies cross the placenta and help protect the newborn, not as a routine childhood jab

The focus of the programme is to reduce the incidence and severity of RSV disease in infants. While RSV can occur at any age, babies under one year of age are at the greatest risk of hospitalisation with more severe RSV.

4. About the prematurity signal in the trial

• A small increase in preterm births was noticed in the study
• It was not statistically or biologically convincing
• It has not been seen in real-world use

Our advice for you
What we know clinically is:

• RSV can be serious in pregnancy or early infancy, increasing the chance of hospitalisation, needing oxygen, or other complications.
• Babies born preterm or smaller are even more vulnerable to severe RSV.
• The maternal RSV vaccine can reduce severe RSV illness in babies by around 70–80% in the first few months of their life.

So, for you in your situation, the benefit of the vaccine is probably even stronger.

Ideally the vaccine should be given in week 28 or soon after that, so there is sufficient time for the mother to make high levels of antibodies and for these to transfer across the placenta, including if the baby is born prematurely. Giving the vaccine around week 28 also increases the potential for babies who are born prematurely to benefit.

Hello, @Alwaystiredzzz, thank you for your question.

This is an easy one for me, as this happened to me when I was a child, and it turns out my few spots were not enough, and I had no immunity to chickenpox and had to be vaccinated as an adult.

It is safe for your daughter to have the chickenpox-containing MMRV vaccine, even if you’re not sure whether she’s had a chickenpox infection before. The antibodies she made if she did have chickenpox infection previously will stop the vaccine viruses from replicating and neutralise them. Any antibodies she has from a previous infection will also be boosted by having the vaccine.

Besides protecting against chickenpox, the MMRV vaccine also protects against measles, mumps and rubella so it is important to have this vaccine to prevent these infections.

So, in summary:

• The vaccine is safe for children who may have had mild or uncertain chickenpox, and it will help protect them if they haven’t had the infection.
• If your child has had chickenpox before, the vaccine won’t cause harm.
• Because it’s often hard to tell from just a few spots, we would usually recommend giving the vaccine if there’s any uncertainty, so your child is protected.

Hi @KruelladeVille23 - thank you for your question.

The UK vaccination schedule differs from some other European countries because it’s designed to maximise protection during early childhood, when children are most at risk of catching measles, mumps, and rubella and before they start mixing at school.

Why the UK gives a second MMR dose at 3 years 4 months to 5 years

• The first dose works for most children, but about 1 in 10 don’t develop full immunity after the first shot.
• The second dose acts as a “catch-up” to ensure almost all children are fully protected before starting school, where exposure risk is higher.
• This timing helps prevent outbreaks in nursery and early school settings, which is where most measles cases occur.

Why some countries wait until 12:

• Some European countries give the second dose later because their disease patterns, school entry ages, and historical vaccination coverage are different.
• Waiting until later can work in populations where measles exposure in early childhood is rare, but it leaves children less protected in the early school years.

The UK schedule is more proactive, aiming to get almost every child immune before school. That’s why the NHS recommends the second dose at 5, even if other countries take a later approach.

If you would like further information, we recommend these:
https://www.nhs.uk/vaccinations/mmr-vaccine/
https://www.nhs.uk/vaccinations/why-vaccination-is-important-and-the-safest-way-to-protect-yourself/

Hello @OopsieeDaisy - thank you for your question.

1. One dose vs two doses of chickenpox vaccine

• One dose of varicella (chickenpox)-containing vaccine has been shown to be highly effective at preventing severe chickenpox - and any breakthrough infection is usually very mild (often just a few spots and a low fever). Most children develop protection after one dose of chickenpox vaccine and there is no evidence that this protection wears off over time.

• The UK recommends a two-dose schedule as standard to boost immunity further and reduce the small chance of breakthrough infection later.

2. Risk of “declining immunity”

• It’s understandable to worry that one dose might “wear off”, but research shows that even a single dose gives lasting partial protection, and if a child catches chickenpox after one dose, the disease is usually milder than if they had never been vaccinated.

• There’s no evidence that a single-dose vaccine makes chickenpox worse than if they had caught it naturally. Breakthrough cases tend to be mild, not severe.

3. Timing of a second dose
If you were to give a second dose, it’s still effective if given more than 6 weeks after the first. In fact, that’s standard practice — the minimum interval in the UK is at least 4–6 weeks, and boosters can be given later if desired.

4. Do you need the second dose?
For most healthy children, one dose is enough to prevent severe disease, and most won’t need a second dose.

If you would like further information, we recommend these:
https://www.nhs.uk/vaccinations/why-vaccination-is-important-and-the-safest-way-to-protect-yourself/