BCG Vaccine UK: What It Is, Who Gets It, When It’s Given, and the Scar Explained
The BCG vaccine — known as the TB jab — is one of the most recognised vaccines in the UK because of the distinctive small scar it leaves on the upper left arm. Older generations in the UK were vaccinated at school age as part of a universal programme that ended in 2005. Today, BCG is only offered to babies and individuals at higher risk of tuberculosis, not routinely to all children. If you have been told your baby needs the BCG vaccine, or if you are wondering about the scar process, this guide covers everything you need to know.
This article is for informational purposes only. Always consult your GP, health visitor, or midwife for advice specific to your or your child’s situation.
What Is the BCG Vaccine?
BCG stands for Bacillus Calmette-Guérin — named after the two French scientists, Albert Calmette and Camille Guérin, who developed it in the early 20th century. The BCG vaccine protects against tuberculosis (TB), a serious infectious disease caused by the bacterium Mycobacterium tuberculosis.
TB mainly affects the lungs, but can affect any part of the body including the lymph nodes, bones, joints, kidneys, and the brain (TB meningitis). It can become very serious if not treated, with treatment typically lasting at least six months. While TB is not common in the UK, cases have been increasing, and certain populations are at significantly higher risk.
The BCG vaccine is a live attenuated vaccine — it contains a weakened form of Mycobacterium bovis, the bovine (cattle) form of TB. Because the bacteria are alive but weakened, the vaccine triggers an immune response without causing actual TB. This is also why BCG cannot be given to people with weakened immune systems.
Is the BCG Vaccine Part of the Routine NHS Schedule?
No. The BCG vaccine is not part of the routine NHS childhood vaccination schedule. It is only recommended for specific groups of people at higher risk of exposure to TB.
The UK discontinued universal school-age BCG vaccination in 2005. Before that, the BCG was routinely given to all children at secondary school age (around 13-14 years old). The change was made because TB rates were low enough in the general population that universal vaccination was no longer considered cost-effective — instead, targeting higher-risk groups was judged more efficient.
If your baby needs the BCG vaccine, your midwife, health visitor, local health centre, or hospital will let you know. For older children and adults who think they may need it, speak to your GP surgery.
Who Gets the BCG Vaccine in the UK?
The NHS recommends the BCG vaccine for the following groups:
Babies at Higher Risk of TB
Most BCG vaccinations in the UK today are given to babies. A baby is considered higher risk if:
- They are born in an area with a high rate of TB — historically areas where there are 40 or more TB cases per 100,000 population, which includes many London boroughs and some other urban areas. Your local NHS trust or health visitor will advise whether your area qualifies
- One or more of their parents or grandparents was born in a country with a high rate of TB — this includes most sub-Saharan African countries, parts of South and Southeast Asia, and other regions where TB is endemic. A full list of high-TB countries is available on the GOV.UK website
- They have close contact with someone who has active TB
Travellers and Healthcare Workers
- Children aged 16 or under who will be staying for more than three months in a country with high TB rates and will be staying with friends, family, or local people
- Healthcare workers over 16 who are likely to be in contact with TB patients
Adults New to the UK
- Adults who have come to live in the UK from sub-Saharan Africa or a country with very high TB rates may need the BCG vaccine if they have not been vaccinated before
When Is the BCG Vaccine Given?
| Group | When BCG Is Given |
| Babies (most common) | Usually by 28 days old — after the newborn blood spot test has returned results (BCG cannot be given to babies with SCID) |
| Older children | As soon as identified as higher risk; check with GP or local immunisation team |
| Travellers under 16 | Before travel to a high-TB country |
| Healthcare workers over 16 | Before beginning work involving contact with TB patients |
| Adults new to UK from high-TB countries | As soon as identified as requiring vaccination; contact GP |
For babies, the BCG vaccine is given after the newborn blood spot (heel prick) screening test results have returned. This is because one of the conditions screened for — severe combined immunodeficiency (SCID) — is a contraindication to BCG vaccination. Babies with SCID cannot receive BCG because they lack the immune system to respond safely to a live vaccine.
If your baby needs the vaccine and you have not been offered it, contact your midwife, health visitor, or local NHS immunisation team.
Where Is the BCG Vaccine Given?
The BCG vaccine is always given as an injection into the upper part of the left arm — specifically the deltoid region. The left arm is used by convention, so that any resulting scar is easily identifiable as a BCG vaccination scar when checking vaccination history. The injection is given intradermally — into the skin layer itself rather than into the muscle, which is why you can see an immediate reaction.
You will only ever need one dose of the BCG vaccine. It is given once and not repeated.
The BCG Scar: What to Expect Step by Step
The BCG vaccine produces a characteristic reaction at the injection site that progresses over weeks and months. This is a normal, expected immune response — not a sign that anything has gone wrong.
| Timeframe | What You Will See |
| Immediately after injection | A raised white blister appears at the injection site. This shows that the vaccine has been correctly delivered into the skin layer. It will disappear within 30 minutes to a few hours. |
| 2 to 6 weeks later | A small red spot (approximately 3-4mm) appears at the vaccination site. This is the expected immune reaction beginning. |
| Over the following weeks | The spot may develop into a small blister. It may ooze a small amount of fluid, which is normal. A crust or scab then forms. |
| 8 to 12 weeks (sometimes 3-6 months) | The scab falls off on its own, leaving a small, flat scar. The scar may appear red initially, but will fade slowly over time. |
The entire healing process typically takes 8 to 12 weeks but can take up to six months in some people. This is completely normal and does not require treatment.
How to Care for the BCG Vaccination Site
The NHS and individual NHS trusts advise the following care for the BCG injection site:
- Leave the site uncovered wherever possible — exposure to air helps it heal
- Do not apply creams, lotions, or ointments to the site until it has fully healed
- Do not use a waterproof plaster or standard adhesive plaster on the site
- If the site is oozing or weeping, cover with a dry dressing (not a plaster) until a scab forms, then remove
- For bathing or showering: leave the area uncovered, take care not to rub it, and pat it dry gently afterwards
- For swimming: cover with a waterproof plaster, but remove it immediately after swimming and pat the skin dry
- Do not keep the area consistently wet
- No other vaccines should be given in the same arm for three months after BCG
See a GP if: the blister appears to have become infected (increasing redness, warmth, or spreading beyond the immediate site), if it has not healed after six months, or if a larger abscess develops at the site.
BCG Vaccine With No Mark: What Does It Mean?
Some people do not develop a visible scar after BCG vaccination. This is more common in some individuals than others and does not mean the vaccine failed to work.
The official NHS and clinical guidance is clear: if no scar develops, you will not be re-vaccinated. Per Kent Community Health NHS: ‘Even if no scar develops, we do not re-vaccinate.’ The absence of a scar does not indicate that the immune response did not occur — it simply reflects individual variation in how the skin heals after the intradermal injection.
For clinical purposes, the presence or absence of a BCG scar is used as an indicator of prior BCG vaccination history. If you have had BCG but have no scar and cannot provide a reliable vaccination history, your clinician may assess whether BCG vaccination is appropriate using tuberculin skin testing (Mantoux test) or an IGRA (interferon-gamma release assay) blood test before considering vaccination.
Is BCG a Live Vaccine?
Yes — the BCG vaccine is a live attenuated vaccine. It contains weakened (but living) Mycobacterium bovis bacteria. Because it is live, it stimulates a stronger and longer-lasting immune response than inactivated vaccines, but it also means it cannot be given to everyone.
BCG is contraindicated (should not be given) in:
- Babies with severe combined immunodeficiency (SCID)
- People with HIV infection or other conditions that significantly weaken the immune system
- People currently receiving chemotherapy, high-dose steroids, or other immunosuppressant treatments
- People with active TB or a previous BCG vaccination
- During pregnancy — BCG is not given during pregnancy. BCG vaccination should be postponed until after delivery
How Long Does the BCG Vaccine Last?
The duration of protection from BCG is the subject of ongoing research and is not precisely defined. Studies have consistently shown that BCG provides significant protection against severe forms of TB — particularly TB meningitis and disseminated TB in young children — for at least 15 to 20 years. Some evidence suggests protection may persist longer in certain populations.
No booster dose of BCG is recommended in the UK. You receive one dose and it is not repeated, even if protection may wane over time. The rationale is that BCG is primarily intended to protect the most vulnerable age groups (young children) from severe disease, and re-vaccination has not been shown to provide meaningful additional benefit.
Frequently Asked Questions
What is the BCG vaccine?
BCG (Bacillus Calmette-Guérin) is a live attenuated vaccine that protects against tuberculosis (TB). It contains a weakened form of Mycobacterium bovis — the cattle form of the TB bacteria. In the UK, it is given to babies and individuals at higher risk of TB, not to all children routinely.
Who gets the BCG vaccine in the UK?
Babies at higher risk of TB — those born in high-TB areas or with parents or grandparents from high-TB countries — are usually offered BCG by 28 days old. It is also offered to some travellers, healthcare workers, and adults new to the UK from high-TB countries. It is not part of the routine childhood immunisation schedule.
When is the BCG vaccine given to babies?
Usually by 28 days old, after the newborn blood spot screening results have been received. This delay allows clinicians to confirm the baby does not have SCID (severe combined immunodeficiency), which would make BCG dangerous. If your baby needs BCG and has not been offered it, contact your midwife or health visitor.
What does the BCG vaccine scar look like?
The BCG scar is a small, flat circular scar on the upper left arm. It forms over 8-12 weeks (sometimes up to six months) after vaccination, following a progression from a white blister at injection → small red spot at 2-6 weeks → blistering and scabbing → small flat scar. It is a normal expected reaction.
What if there’s no BCG scar?
No scar does not mean the vaccine did not work. Some people simply do not form visible scars after BCG. You will not be given a second dose. If no scar develops, you are not re-vaccinated. If there is uncertainty about vaccination history for clinical purposes, Mantoux or IGRA testing may be used to guide decisions.
How long does the BCG vaccine last?
Evidence suggests BCG provides significant protection for at least 15-20 years, particularly against severe TB in young children. No booster dose is recommended in the UK. One dose is given once in a lifetime.
Final Thoughts
The BCG vaccine occupies a unique place in UK vaccination history — once given to virtually every secondary school-age child, now targeted to the babies and individuals most at risk of tuberculosis. For parents of babies in higher-risk groups, the vaccine is important and effective, particularly in preventing the most severe forms of TB such as TB meningitis. The scar process — which can alarm parents who are not expecting it — is a normal immune response and typically resolves within a few months. If your baby has been identified as needing BCG and you have not been offered it, contact your midwife or health visitor promptly, as it should be given by 28 days old.This article is for informational purposes only. Consult your GP or health visitor for advice specific to your or your child’s situation.