Why do I need the flu jab in pregnancy?

Worried about having a flu vaccine? I am a GP and a mother of 3. I have a flu vaccine as a healthcare worker, I had it when I was pregnant and would have no worries about having the flu vaccine if I were to be pregnant again.

Here, I'm going to answer your most-asked questions about the flu vaccine that's offered to pregnant women, so that you can be sure you have all the info you need…

Why do I need the flu jab when I’m pregnant?

The flu vaccine protects both you and your unborn baby from flu and from flu's potential complications. Unfortunately, pregnant women have a higher chance of complications if they get the flu, particularly if they get it in late pregnancy¹. Flu itself can make you feel extremely unwell but can also have some complications which can affect both you and your unborn baby.

The commonest complication which could affect you is bronchitis and this can also lead to pneumonia (a potentially serious lung infection) or, extremely rarely, maternal death. Complications that can affect your pregnancy and unborn baby include premature birth and low birthweight, and unfortunately also, rarely, stillbirth or death after delivery.

Of course, you may have had been offered a flu jab before – perhaps because you're a frontline health or social care worker or because you have a chronic health condition (such as diabetes). But if you are pregnant and don't meet one of these qualifying criteria, this year may be the first time you are offered the vaccine.

Why are we being told it’s more important than even have the flu jab this year?

Covid-19. It may seem like the answer to most questions asked in the past 18 months but Covid-19 is a particularly key reason why a flu vaccine in pregnancy is seen as so important this year. Whatever the current restrictions are, Covid-19 has not gone away, and while it is still circulating, it's possible that you could catch both flu and Covid-19 at the same time – and that combination can be particularly serious.

That's because both Covid-19 and influenza are caused by (different) respiratory viruses, affecting your lungs and your ability to breathe. Research from Public Health England has shown that, if you are infected with flu and Covid-19 together, you may be more seriously unwell than if you're only affected by one of them. This double infection can affect both you and your unborn baby.

Covid-19 was also responsible for last year being a low flu infection year – because we were all under various stages of tiers, lockdowns and other restrictions and were not mixing as normal. But this year when there aren't restrictions, and we are mixing and meeting other people, experts expect there to be a lot of flu virus around, and for us to be less resistant to it after our year of distancing from each other.

How do I know the flu vaccine is safe in pregnancy?

The flu vaccine is safe to use at all stages of pregnancy. You will be offered a flu vaccine which protects against 4 different strains of the flu virus but the vaccine itself does not contain any live virus.²

Will the flu jab harm my baby?

There is no increased risk to babies from having the flu vaccine. In fact, it is not having the vaccine and getting flu which is potentially more likely to cause harm.²

If I have the flu vaccine, will my baby be protected from flu when they're born?

Yes! If you get the flu vaccine when you are pregnant, the protection that you get from the vaccine will protect not only you but your baby. The antibodies you make in response to the vaccine will be passed onto the baby in the womb and this protection will continue to protect them in their first few months of life. This is particularly important as babies younger than 6 months old who catch flu are more likely to develop complications from the infection.

What are the side effects of the flu vaccine?

The commonest side effect is a local reaction at the site of the injection – which will be on your upper arm – such as soreness, redness, tenderness or swelling. If you keep moving your arm, the discomfort should improve in a few days. Other side effects include feeling generally unwell or tired, having a fever or headache, and aches and pains. If you get these symptoms, they tend to improve within a few days – and it's safe to take paracetamol for pain in pregnancy.

It's worth remembering that all medicines have the potential for side effects but those associated with the flu vaccine are generally mild and short-lived – unlike flu itself, which can be more serious and have complications.

What's in the flu jab exactly?

The flu vaccine contains inactivated flu virus – so there's no live virus – and it cannot cause a flu infection. This inactivated virus will 'teach' your body's immune system to identify and respond to real, live flu viruses if it comes across them in the future.

There are different brands of flu vaccine used by the NHS in England but they can contain a small amount of egg protein (as the virus is often grown on hen's eggs). If you know that you have an allergy to eggs, then alternative options which are low-egg or egg-free are available.

The vaccine may also contain sodium and potassium salts: these are used as acidity regulators to keep the vaccine stable. The amounts of these salts in the vaccine are extremely small – and we have sodium and potassium naturally in our bodies and in the food we eat. A chemical called polysorbate is also often present, and used as an emulsifier, to keep the ingredients in the vaccine together.

In addition to these vaccine 'ingredients', there may also be trace (extremely tiny) amounts of products used in the manufacturing process. These include formaldehyde (which is found in the body), which is used to inactivate the virus, and antibiotics, such as neomycin, which are used to prevent bacteria contaminating the vaccine. If you are allergic to neomycin, please talk to your GP before having your vaccine.

How effective is the flu vaccine? Does having the vaccine mean I definitely won't get flu?

The flu vaccine works better in some years than others but Public Health England research continues to show it to be very effective overall.³ And there's no doubt that vaccines save lives. Plus, importantly, if you are vaccinated, it also helps prevent you spreading flu to others, including your baby once they are born – as we've explained above, babies are at risk of becoming seriously unwell if they catch the flu themselves.

There are lots of different flu viruses and strains, and the vaccine helps to protect you against the main ones that are circulating at the moment but it is possible that you may still get the flu if you're infected by a different strain. However, if you have had the flu jab, you are likely to have the illness more mildly, less likely to have complications and the infection won't last as long as if you didn't have the vaccine.

It takes approximately 2 weeks for your immunity to flu to develop after having the vaccine, so if you are exposed to a flu virus in the few days before your jab or in the fortnight after having it, you may still develop flu.

Can the flu jab give me flu?

No, the flu jab cannot give you flu. It simply does not contain any live virus which could make you unwell. Some people may feel unwell, with flu-like symptoms, as a side effect of the vaccine but these are generally mild and pass in a few days, while flu itself can be more serious.

Why is the flu vaccine for pregnant women an injection? Why can't I have the nasal spray like children can?

The vaccinations which have been approved for use in pregnant women are all injectable vaccinations. Nasal flu vaccines work well in children⁴ but studies are so far inconclusive on whether or not they work better in adults. Currently, the nasal flu vaccine is only approved for use in children.

Can I have my flu jab at the same time as my whooping cough jab? Is that safe?

It's possible to have both the whooping cough and flu vaccines at the same time – and is safe to do so – but because you need to have the whooping cough vaccine at a specific stage of your pregnancy, it might not work for you to have both vaccines together.

It's recommended that you have a whooping cough vaccine between weeks 16 and 32 of your pregnancy in order to protect your baby from whooping cough. But it's important to have the flu vaccine in the winter months, whatever your stage of pregnancy. So if the timing for your whooping cough vaccine overlaps with the winter flu vaccine season, by all means have them both at once but please don't put off your flu jab waiting to have them both together.

Can I have my flu jab at the same time as a Covid jab or Covid booster?

Yes, if you haven't yet had your 2 Covid jabs, or your 2nd Covid vaccination was at least 6 months ago and you are due to have a Covid booster now, it's fine to have both jabs at the same time. However, if it's more complicated to arrange to have them both at the same time, you may prefer to have them separately. Don't put off either jab waiting to have them both together.

I would also urge you, if you have not had your Covid jabs already (including your booster, if offered), to get them as soon as possible. Having Covid-19 when you're pregnant poses risks both to you and your unborn baby.

At how many weeks pregnant should I have a flu jab?

You can have the flu jab at any stage in your pregnancy. The flu vaccine is generally available from September of each year. You do not need to wait to reach a particular point in pregnancy to have the vaccine. If you are pregnant, book it in!

Is it safe to have the flu jab before 12 weeks?

Yes, it is safe to have the flu vaccine at any stage in pregnancy, including before 12 weeks. If you have not yet had your 1st NHS antenatal appointment, you may not yet be registered with a midwife, so you may need to arrange to have the vaccine through your GP surgery, or a pharmacy offering it free on the NHS, rather than through your midwife and antenatal clinic.

I'm pregnant and breastfeeding. Is it safe for me to have the flu vaccine?

The flu vaccination is safe both in pregnancy and if you're breastfeeding. If you are breastfeeding and pregnant, then you will be able to get the flu vaccine free on the NHS. If, however, you are breastfeeding but not pregnant, a flu vaccine is not free, unless you have a chronic health condition or meet another criteria to have a flu vaccine on the NHS.

Where can I have a flu jab?

If you are registered for antenatal care, it is common practice for your midwife to arrange the flu vaccine for you. Or you can arrange to have your flu vaccine yourself, through your local GP surgery or pharmacy.

Do I have to pay for the flu jab?

No, the flu vaccination is offered free on the NHS to all pregnant women.

If I had a flu jab last year, do I need another one?

Whether or not you had a flu vaccine last year, if you are pregnant, you need a new flu vaccine this year! This is because the strains within the flu vaccine are changed each year in response to the new flu viruses circulating to try to ensure that it is the most effective vaccine it can be each year. Your immunity from last year's vaccine may also be declining, so a flu vaccine is needed each year, if you are eligible.

If they change the flu jab each year, does it go through the same safety checks again?

Yes, the processes around safety checks, testing and quality control are rigorous and completed each year. These processes are started in the early part of each year before the vaccine will be needed, and from then on safety checks and monitoring are always taking place. The Medicines and Healthcare Products Regulatory Agency (MHRA) only grants licences for vaccines after expert review of the safety data.

Where can I find out more?

If you would like further information about the flu vaccination in pregnancy, please talk to your antenatal team or visit the dedicated flu vaccine in pregnancy page on the NHS website.

References:

<sup>1 Pregnancy as a risk factor for severe outcomes from influenza virus infection: a systematic review and meta-analysis of observational studies. Vaccine 2017 Jan 23: 35(4): 521-528 doi: 10.1016/j.vaccine.2016.12.012
2. Quadrivalent Influenza Vaccine (split virion, inactivated), suspension for injection in pre-filled syringe EMC patient leaflet. August 2021
3. Surveillance of influenza and other respiratory viruses in the UK. Winter 2019 to 2020. Public Health England
4. Fluenz Tetra nasal spray suspension influenza vaccine (live attenuated, nasal). EMC SmPC July 2021</sup>

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