COVID-19 Vaccine in Pregnancy, With a Weakened Immune System or With Allergies

Some people need more than a standard check before a COVID-19 vaccine. Pregnancy, breastfeeding, a weakened immune system, allergies, past heart inflammation and bleeding problems all raise reasonable questions, and in almost every case vaccination can go ahead with the right preparation.

This guide covers what the evidence says about the COVID vaccine in pregnancy and in each of these other situations, and what to tell us before your appointment. It is part of our guide to the 2026/27 COVID-19 booster.

The COVID-19 vaccine in pregnancy

COVID-19 can be more serious in pregnancy. Earlier in the pandemic, pregnant women with COVID-19 were more likely to need intensive care, and during the Delta wave UK studies found higher rates of stillbirth and premature birth after infection. Those risks fell considerably with Omicron, but severe illness remained more common in unvaccinated than in vaccinated pregnant women. Risk is higher for women who are overweight, aged 35 or over, of Black or Asian ethnicity, or living with diabetes, high blood pressure or asthma.

The vaccines contain no live virus, so they cannot infect mother or baby, and national guidance knows of no risk from non-live vaccines in pregnancy. Animal studies were reassuring, and large observational studies of women vaccinated during pregnancy in the United States found no rise in poor pregnancy outcomes. Most of that data covers the second and third trimesters; first-trimester data is more limited, but no increase in miscarriage has been seen. No pregnancy test is needed beforehand, and being vaccinated before you knew you were pregnant is not a cause for concern.

Pregnancy on its own is not an NHS group for a COVID-19 vaccine this winter, and NHS inform lists the groups that are. Bruntsfield Pharmacy explains who qualifies for a free COVID-19 vaccine in Scotland. A COVID-19 vaccine can be given alongside the flu, RSV and whooping cough vaccines offered in pregnancy. If you are pregnant, mention it when you book and we will go through the evidence with you before anything is decided.

Breastfeeding

There is no known risk from a non-live vaccine while breastfeeding, and JCVI advises that breastfeeding women can be offered any suitable COVID-19 vaccine. In studies of recently vaccinated women, the vaccine’s mRNA was not detected in breast milk, while protective antibodies were. There is no need to stop or pause feeding.

A weakened immune system

A weakened immune system, or immunosuppression, means the body is less able to fight infection because of a condition or its treatment. National guidance gives examples for people aged 16 and over.

COVID-19 vaccines are safe in this group, but the response can be smaller, and some people with severe immunosuppression make little detectable antibody. Even so, many gain protection, and protection against severe illness may remain when antibody levels are low because of the immune system’s memory cells.

Timing and extra doses

Vaccines work best when immunosuppression is at its lowest. Where treatment is planned, national guidance suggests vaccinating at least two weeks before it starts, or during a break in treatment. Any change to your treatment must come from your specialist: never stop or delay a medicine to fit around a vaccine without their advice. People with severe immunosuppression may be advised to have extra doses outside the usual campaigns, ideally 8 to 12 weeks apart, or as little as three weeks apart on specialist advice. If you test positive for COVID-19, ask your GP or specialist whether you should be assessed for treatment.

Allergies

Allergy is the most common reason people ask whether they can have a COVID-19 vaccine, and the answer is usually yes. Severe allergic reactions to the vaccine are very rare. National guidance sorts allergy history into three groups.

Based on table 5 of the COVID-19 chapter of the Green Book (UKHSA).

PEG, short for polyethylene glycol, is part of the fatty coating of the mRNA vaccines. It also turns up in some laxatives, bowel-cleansing preparations and long-acting steroid injections. The protein-based vaccine uses polysorbate 80 instead. Known allergy to PEG is rare and accounts for only a minority of allergic reactions after COVID-19 vaccines, and many people who had an apparent reaction to one dose go on to have the same vaccine again safely.

The product information for the mRNA vaccine we use recommends observation for at least 15 minutes after vaccination, while the NHS programme has suspended the routine wait for people with no history of allergy. Because we only stock the mRNA vaccine, if you need a different product or vaccination in a hospital setting, we will explain why and advise where to go next.

Heart inflammation, bleeding problems and other conditions

Myocarditis or pericarditis after an earlier dose

If you developed myocarditis or pericarditis after a COVID-19 vaccine, further doses are normally put on hold until a clinician has assessed whether the vaccine was the likely cause. If another dose is needed, national guidance recommends waiting until you have fully recovered and at least 12 weeks after the previous dose, with the choice of vaccine guided by the specialist. If you have had heart inflammation for another reason, tell us when you book.

Blood thinners and bleeding disorders

People on stable anticoagulation can usually have the vaccine into the muscle. On warfarin, your INR checks should be up to date and your latest result below the top of your target range. A fine needle is used, followed by firm pressure for at least two minutes without rubbing. People with a bleeding disorder such as haemophilia can be vaccinated into the muscle if a doctor familiar with their bleeding risk agrees.

Other conditions

A history of Guillain-Barré syndrome or erythema multiforme is not a reason to avoid vaccination. People with a history of capillary leak syndrome, a very rare condition, should get specialist advice first. If you have had immune thrombocytopenia (ITP), your doctor may suggest a platelet check two to five days after vaccination.

How to get started

1. Book online. Use the booking calendar on this page or call 0131 563 6824. See our COVID-19 vaccination page and vaccine prices page for details.
2. Tell us what applies to you. Mention pregnancy or breastfeeding, allergies, past reactions, immune treatments, heart inflammation and any blood thinner.
3. Attend your appointment. We go through your history. If the vaccine is right for you, it is given as a single injection into the upper arm.
4. Leave with aftercare advice. We explain what to expect and which symptoms mean you should get help.

Extra care and the COVID-19 vaccine: your questions answered

Does it matter which stage of pregnancy I am at?

No stage of pregnancy is ruled out. Most of the safety data comes from women vaccinated in the second and third trimesters. Data from the first trimester is more limited, but no increase in miscarriage has been seen. Talk it through with us or your midwife if you are unsure.

I was vaccinated before I found out I was pregnant. Is that a problem?

No. The vaccine cannot cause infection in you or your baby, and national guidance does not treat vaccination in early pregnancy as a cause for concern. Mention it to your midwife so that it is on your record.

Can the vaccine reach my baby through breast milk?

In studies of recently vaccinated women, the vaccine’s mRNA was not found in breast milk, but protective antibodies were. You can carry on breastfeeding as normal.

I am allergic to penicillin. Can I have the COVID-19 vaccine?

Yes. When the cause of an allergy is known, as with penicillin, it does not stop you having the vaccine, even if your reaction was severe. Do tell us about it when you book.

I had chest pain after an earlier COVID-19 vaccine. Can I have this one?

Tell us before you book. If it was diagnosed as myocarditis or pericarditis, further doses are normally deferred until a specialist has assessed you. If it was never looked into, speak to your GP first so that the cause can be checked.

I have haemophilia. Can I have the injection?

Usually, yes, if a doctor who knows your bleeding risk agrees that an injection into the muscle is reasonably safe for you. If you have regular treatment to prevent bleeding, the vaccine can be timed shortly after a dose.

For what is in this season’s vaccine and how well it protects, read our guide to the 2026/27 COVID-19 booster.

This page gives general information and is not a substitute for a personal clinical assessment. COVID-19 vaccines are prescription-only medicines, so we check that vaccination suits you before giving one. For side effects, speak to your pharmacist or GP, or call NHS 24 on 111. In an emergency, call 999.

Sources: UKHSA, the Green Book, chapter 14a, COVID-19, 10 September 2026; Scottish Government, SGHD/CMO(2026)18; Summary of Product Characteristics for the XFG-adapted 30 microgram mRNA vaccine (emc); NHS inform.