Mantoux test, Quantiferon test & BCG vaccines
At GP Matters we provide both the BCG vaccine and Tuberculosis (TB) testing.
You may need to provide evidence of a tuberculosis (TB) test as part of a visa application.
Tuberculosis (TB) is an infectious bacterial infection, spread through inhaling tiny droplets from coughs or sneezes of an infected person. TB is caused by the bacteria Mycobacterium tuberculosis and remains one of the top infectious disease killers worldwide. TB is found in most countries of the world, but the highest incidences are in Africa and Asia. In 2014, 9.6 million people fell ill from TB and 1.5 million people died (WHO data). It is estimated that one third of the world’s population has Latent TB (have infection, but no symptoms of disease).
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.
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
High temperature or fever
Unintentional weight loss
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.
TB Vaccine – one lifetime dose
The BCG vaccine is a live vaccine, which means that it contains a weakened strain of actual TB bacteria, Mycobacterium bovis. The vaccine encourages the body to fight the TB bacteria without contracting TB, and therefore building immunity to the disease.
Who should have the BCG Vaccine?
The BCG vaccine can be given from birth and is particularly recommended to babies and young children to provide protection from childhood TB and TB meningitis. As well as adults who are at a high risk of infection.
All infants born and living in areas of the UK with high incidence of TB
Infants or children with a parent or grandparent from a country with high incidence of TB
Certain groups of travellers to high incidence countries
Anyone at risk of TB due to their occupation, such as healthcare workers
Exclusions to BCG vaccine
The BCG must not be given in the following situations:
If you are pregnant or breastfeeding
If you have already had the BCG vaccine
If you had a live vaccine in last 4 weeks
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, sever HIV infection or due to medications, such as oral steroids, cancer therapies and immunosuppressants.
If you have an illness with a high fever (greater than 38.5 degrees Celsius) on the day of the vaccination.
Booster doses- There is no need for further doses of the BCG vaccine- it should be given only once in a lifetime.
Common Side Effects
NORMAL REACTION to the Vaccine
In the vast majority of those vaccinated, a blister forms at the injection site between 2 to 6 weeks later. The blister then becomes a open sore, which may leak fluid. The sore will eventually crust over and heal to leave a flat scar. This process may take months to occur.
Localised side effects, such as pain, redness, bruising and swelling are common with the BCG vaccine.
Uncommon side effects (occurring in 1 per 100-1 per 1000 individuals) include fever, headache, loss of appetite, irritability and enlarged lymph gland near the injection site (in the armpit or the neck). These are normally short-lived and get better by themselves.
Rare side effects include allergic reaction to the vaccine and skin abscess.
The Mantoux test is a widely used test for latent TB. It involves injecting a small amount of a substance called PPD tuberculin into the skin of your forearm. It's also called the tuberculin skin test (TST).
If you have a latent TB infection, your skin will be sensitive to PPD tuberculin and a small, hard red bump will develop at the site of the injection. You will have to return to the clinic (or send us a picture of your arm) 48 to 72 hours after having the test for us to read the reaction.
If you have a very strong skin reaction, you may need a chest X-ray to confirm whether you have active TB disease.
If you do not have a latent infection, your skin will not react to the Mantoux test. However, as TB can take a long time to develop, you may need to be screened again at a later stage.
If you've had the BCG vaccination, you may have a mild skin reaction to the Mantoux test. This does not necessarily mean you have latent TB.
You will have to return (or send us a picture of your arm) 48 to 72 hours later for us to read the 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/or Chest X-ray in the case of positive Mantoux test results depending on the reaction and any symptoms.
QuantiFERON-TB Gold (QFT) is a simple blood test that aids in the detection of Mycobacterium tuberculosis, the bacteria which causes tuberculosis (TB). QFT is an interferon-gamma (IFN-γ) release assay, commonly known as an IGRA, and is a modern alternative to the tuberculin skin test (TST, PPD or Mantoux). Unlike the TST, QFT is a controlled laboratory test that requires only one patient visit and is unaffected by previous Bacille Calmette-Guerin (BCG) vaccination.
QFT is highly specific and sensitive: a positive result is strongly predictive of true infection with M. tuberculosis. However, like the TST and other IGRAs, QFT cannot distinguish between active tuberculosis disease and latent tuberculosis infection, and is intended for use with risk assessment, radiography, and other medical and diagnostic evaluations. Like any diagnostic aid, QFT cannot replace clinical judgment.
The US Centers for Disease Control (CDC) Guidelines recommend the use of IGRAs in all situations in which the TST was historically used, with IGRAs being the preferred test for persons who have been BCG vaccinated or are unlikely to return for TST reading.
The results are available in 3 days