Mantoux & Tuberculosis (TB) Testing

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.

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.

What is a Mantoux Test?

Part of the protein from the TB bacterium is injected under the skin of the forearm. After 48-72 hours, the arm is checked to see if there has been a reaction. If there is latent (non active) TB, moderate redness and swelling is often seen at the site-a positive Mantoux test. If this reaction is more severe active TB is more likely. A mild reaction can also occur if you have had the BCG vaccination. Further investigation may be required either through Quantiferon Gold blood test and in the case of positive Mantoux test results depending on the reaction and any symptoms.

Here at CityDoc we also offer the Quantifern Gold Test.

What is a Quantiferon Gold Test?

This is a blood test, which determines if a person is infected with the tuberculosis bacteria by measuring the immune response to TB proteins in blood. It can be used instead of the Mantoux test or performed if the Mantoux test is positive. Unlike the Mantoux test, it is not affected by the BCG vaccination.

Here at CityDoc we have scheduled clinics specifically for Tuberculosis testing. These are held in our private London Flagship clinics only. If you would like to book an appointment, please call our contact centre on 0333 257 1456.

1) Is the Mantoux Test safe?
The Mantoux test has been around for a long time and has been rigorously tested for safety. The vaccine does not contain any thiomersal (mercury derivative).

2) 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.

3) 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.

4) 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.

5) 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.

6)  Is the vaccine infectious?
The TB bacteria in the vaccine is weakened and cannot be transmitted. Therefore, there is no risk in having your child vaccinated if there are family members who have weakened immune systems or are pregnant.

7)  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.

8) Which BCG vaccine manufacturer do you use? 

The BCG vaccine we use is the licensed vaccine, also used by the NHS, produced by AJVaccines.

9) Does my child need to have a test first before they can have the vaccine?
Children under 5 years of age do not have to be tested first and can have the vaccine directly. Children and adults from 5 years of age would need to have TB testing first to check for immunity or latent infection. This is because it is not advisable to have the BCG vaccine if you already have immunity as it can lead to serious adverse reactions and has no additional benefit on the immune response.

10) How long does the TB skin test last for?
The Mantoux test is valid for 3 months. If more than 3 months have elapsed, then the test would need to be repeated before the BCG vaccine can be given.

11) Can my child go to nursery/school afterwards?
Although the vaccine is live, it is not infectious and therefore, the advice is that children can go to nursery or school provided that they are well to do so. The clinician will advise you during the consultation of the expected reactions to the vaccine.

12) Can we travel after my child has the BCG vaccine?
You can travel after the vaccination provided your child is well following the vaccine. They are not infectious. If you are travelling to a country with a high incidence of TB, it is worth bearing in mind that full immunity to the vaccine can take up to 6 weeks to occur.

13) Can my child go swimming after vaccination?
The doctor will discuss what you can or cannot do following vaccination during the consultation. The current advice is that the injection site does not need to be protected from water. However, once the sore develops, it is best to use a non-adhesive waterproof dressing while swimming to protect the area from infection. You can bathe or shower as normal immediately after vaccination.

14) If my child does not have any reaction or scar, does that mean they are not immune?
Although the reaction and scar occurs in most vaccinated individuals, some do not have this reaction. This does not mean that they are not immune and further vaccination or TB testing is not required.

15) Can my child have the BCG vaccine if they are allergic to egg?
The BCG can be given to individuals with egg allergy, latex (rubber) allergy, as it does not contain these ingredients. For other allergies, please discuss with the doctor during the consultation, who will check the ingredients to ensure it is safe to administer. All our clinicians are trained in the management of severe allergic reactions on adults and children and have adrenaline on site.

 16) Does the BCG vaccine contain animal products?
All the ingredients in the BCG vaccine dare of non-animal origin.