Tuberculosis (BCG) Vaccine

Tuberculosis (BCG) Vaccinations in Hitchin

Tuberculosis (TB) is a serious bacterial infection that mainly affects the lungs, but it can also spread to other parts of the body such as the brain, spine, or kidneys.

Help & Advice

Do I need a Tuberculosis (BCG) vaccine?

Whether you need the BCG vaccine depends on your risk of exposure to Tuberculosis (TB), it’s not routinely given to everyone in the UK.

You may need the TB (BCG) vaccine if:

You’re a baby or child at higher risk
For example, if your parents or grandparents are from a country where TB is common.
You’re planning to live or work abroad
Especially in countries with higher TB rates (parts of Asia, Africa, Eastern Europe, South America).
You work in healthcare or high-risk environments
Such as hospitals, labs, or settings where you may come into contact with TB patients.
You’ve had close contact with someone with TB
In some cases, vaccination or testing may be advised.

You probably don’t need it if:

You were born and raised in the UK with no specific risk factors
You’re not travelling to high-risk areas
Your job doesn’t expose you to TB

Important things to know

The BCG vaccine is most effective in children, particularly for preventing severe forms of TB
In adults, it offers more limited protection, so it’s only recommended in certain situations
Children aged 6 years and over, teenagers and adults will usually require a TB skin test (Mantoux test) before BCG vaccination to check for evidence of previous TB infection. In some circumstances, a TB blood test (IGRA) may also be recommended.

Course

Course of the TB (BCG) Vaccine

The BCG vaccine is given as a single-dose vaccine, rather than a course of multiple injections.

It is usually administered as a small injection into the upper arm. In most cases, only one dose is needed to provide protection, particularly against the more serious forms of Tuberculosis in children.

How the vaccine works

The BCG vaccine is a live, weakened vaccine. This means it contains a harmless form of bacteria related to TB (called Mycobacterium bovis) that has been altered so it does not cause illness in healthy individuals.

After vaccination, the immune system recognises this weakened bacteria and learns how to respond to it. This helps the body build protection so that, if it later comes into contact with TB bacteria, it can respond more effectively and reduce the risk of serious disease.

What to expect after vaccination

A small raised area usually appears at the injection site within a few weeks
This may develop into a small blister or sore before healing
A small scar often remains, which is normal

Additional points

The vaccine is most effective when given in infancy or early childhood
Older children and adults may require a TB test before vaccination to check for prior exposure
Booster doses are not routinely required

Common and rare side effects of the Tuberculosis (BCG) Vaccine

Common side effects

These are expected and usually part of the normal response to the vaccine:

A small raised lump at the injection site
Redness or tenderness in the area
A blister or small sore that may appear after a few weeks
The area may crust over and heal slowly

It’s normal for the vaccine to leave a small scar on the upper arm.

Less common side effects

Swelling of nearby lymph nodes (for example, under the arm)
Mild fever

These usually settle without treatment.

Rare side effects

A larger ulcer (open sore) at the injection site
More significant swelling of lymph nodes, sometimes with pus

Very rare but serious side effects

Infection spreading beyond the injection site (more likely in people with weakened immune systems)
Severe allergic reaction (anaphylaxis), which is extremely rare and treatable

When to seek advice

You should contact a healthcare professional if:

The injection site becomes very swollen, painful, or does not heal
There is significant swelling of lymph nodes
You feel unwell or have concerns about the reaction

Overall safety

The BCG vaccine has been used for many years and is considered safe, especially when given to those who need it. Most reactions are mild and part of the body building protection against tuberculosis.

How do you catch TB?

TB is spread from person to person by coughing or sneezing and someone breathing in the droplets. Normally, prolonged contact with the infected person is required. TB can be transmitted by family members who live together and are in close contact.

What are symptoms of TB?

TB can affect any organ of the body and symptoms relate to the infected organ. However typical symptoms of TB include-:

A persistent cough with phlegm that may include blood
Chest pain
Night sweats
High temperature or fever
Unintentional weight loss
Poor appetite
Tiredness and fatigue

Infants and children and anyone with a compromised immune system tend to get TB of other sites, especially TB meningitis (infection of the lining of the brain).

TB is a curable disease and also a preventable one. However, treatment requires a combination of medications taken for at least 6 months, whereas, prevention is much simpler with a single dose of BCG vaccine, which can be given from birth.

Exclusions to BCG vaccine

The BCG must not be given in the following situations:

If you have already had the BCG vaccine
If you have a past history of TB infection
If you have a positive TB skin test (Mantoux test)
If you have had a previous allergic reaction to any of ingredients in the vaccine (see FAQ section for ingredients)
If you have a weakened immune system such as due to diseases like leukaemia, lymphoma, severe HIV infection or due to medications, such as oral steroids, cancer therapies and immunosuppressants.
If you have a illness with a high fever (greater than 38.5 degrees Celsius) on the day of the vaccination.
Babies under 9 months without a negative neonatal SCID report.

Pregnancy

The BCG vaccine should not be given during pregnancy, due to the risk of a live vaccine.

Breastfeeding

The BCG vaccine should not be given to breast feeding mothers.

Although there have been no harmful effects demonstrated when the vaccine has been given to breast feeding mothers, it is best that vaccination is avoided unless absolutely necessary.

Is the vaccine safe?

The BCG vaccine has been around for a long time and has been rigorously tested for safety. The vaccine does not contain any thiomersal (mercury derivative).

How effective is the BCG vaccine?

The BCG vaccine works best when it is given to young children, as they are more likely to get severe forms of TB and have active disease. The vaccine is around 70-80% effective against prevention of severe forms of TB such as TB Meningitis. It is less effective at preventing lung TB.

Vaccination is only recommended in individuals over 16 years of age if they are at high risk of encountering the infection. This is because there is limited data on how effective the vaccine is in individuals over 16 years of age and no data at all in those over 35 years of age.

Can the vaccine be administered in the leg or other areas of the body to avoid a visible scar.

The current guidance and advice from both The World Health Organisation and The Department of Health is that the BCG vaccine should only be administered in the arm as this reduces the risk of severe adverse reactions. The vaccine is usually given in the left upper arm, which has been shown to produce less reaction. The BCG scar is usually small and flat.

Can other vaccinations be given at the same time?

The BCG vaccine can be given at the same time or any time before or after routine childhood immunisations. There is no need to delay either the BCG vaccine or routine childhood vaccines. However, no other injection should be given in the BCG arm for 3 months. Other sites must be used.

Can the vaccine be given if the child is unwell?

The vaccine should not be given in the presence of a fever (above 38.5 degrees Celsius). If there are minor illnesses such as cold, cough or ear infections, but no fever, the vaccination can be given depending on how well the child is. This will be determined by the clinician in the consultation.

Is more than one dose of the BCG vaccine required?

The BCG vaccine is normally administered once only. There is no evidence that further doses provide any additional protection and indeed, can cause more adverse reactions.

TB screening, Mantoux testing & BCG assessment

We offer tuberculosis (TB) screening services for individuals who require assessment for employment, education, professional registration, occupational health clearance or BCG vaccination.

Our services include:

Mantoux (TB skin) testing
BCG vaccination assessment
BCG scar assessment and documentation
IGRA (TB blood testing) where appropriate
Advice regarding TB screening and vaccination requirements

Mantoux (TB Skin Testing)

The Mantoux test involves a small injection placed just under the skin of the forearm. The test site is then assessed 48–72 hours later to determine whether there is evidence of previous exposure to tuberculosis (TB).

Mantoux testing is commonly required for:

Healthcare workers
Students entering healthcare courses
Care home and social care staff
Occupational health screening
Visa and immigration requirements
Individuals requiring BCG vaccination

In many cases, particularly for those aged 6 years and over who are being considered for BCG vaccination, a Mantoux test may be required before vaccination can be given.

BCG Scar Assessment

Some employers, universities and occupational health providers require evidence of previous BCG vaccination.

Our clinicians can assess and document the presence of a BCG scar and advise whether any further TB screening or testing may be required.

IGRA Blood Testing

In some circumstances, a TB blood test known as an Interferon Gamma Release Assay (IGRA) may be recommended instead of, or alongside, a Mantoux test.

IGRA testing may be appropriate for:

Occupational health screening
Healthcare worker clearance
Individuals who have previously received BCG vaccination
Those unable to return for Mantoux test reading
Situations where additional information regarding previous TB exposure is required

Unlike the Mantoux test, IGRA testing requires a blood sample and does not require a follow-up appointment to interpret the result.

Our clinicians can advise on the most appropriate form of TB screening based on your individual circumstances and any employer, university or occupational health requirements.