All people, except infants <6 months of age, should have a tuberculin skin test (TST; Mantoux) before BCG vaccination. Only immunocompetent people who have induration of <5 mm after a TST should receive BCG vaccine.
The TST uses a tuberculin purified protein derivative. This causes a hypersensitivity reaction in people who have a Mycobacterium tuberculosisinfection. Hypersensitivity reactions can also occur in:
The measles virus inhibits the response to tuberculin. Tuberculin-positive people may become tuberculin-negative for 4–6 weeks after measles infection, and measles-containing vaccines have a similar effect. 6,7
Because of this, the TST may be unreliable for at least 4–6 weeks in people who have received a measles-containing vaccine.
Interferon-gamma release assays (IGRAs) are a type of blood test that can detect M. tuberculosisinfection, but the TST is still the preferred method of screening for tuberculosis, unless the person has previously received BCG vaccine.8
The Department of Health acknowledges the traditional owners of country throughout Australia, and their continuing connection to land, sea and community. We pay our respects to them and their cultures, and to elders both past and present.