Household contacts of people with tuberculosis (TB) have a high risk of getting TB themselves, at around 2%. It is currently difficult to detect TB in its early stages, or predict who will go on to have TB, and therefore preventive treatment is not widely used. Most contacts are asymptomatic and current approaches rely mainly on symptom-based screening and sputum testing, which often miss early or hidden disease. As a result, many infections are only identified once the disease has progressed.

In a large prospective study, the team evaluated the Cepheid Xpert MTB Host Response (MTB-HR) blood test in more than 2,000 household contacts in Tanzania, Zimbabwe, and Mozambique. Participants aged 10 years and older were followed for up to two years with regular clinical, imaging, and laboratory assessments. At each visit, a finger-prick blood sample was analyzed using the GeneXpert platform.