ACT 1 & 2

Tuberculosis household contact investigation studies


A substantial proportion of patients with TB in Vietnam do not come to the attention of the health care services. Screening for tuberculosis is therefore an important priority for TB control. The Active Case Finding in Tuberculosis (ACT) studies aim to test strategies for screening in different settings. The ACT1 and ACT2 studies focus upon screening household contacts of patients with infectious TB for tuberculosis. These studies run from 2009-2015. The initial pilot study, called ACT1 involved screening of more than 500 household contacts of patients with smear positive tuberculosis in 4 districts in Hanoi. This study found a high rate of TB among the contacts, around three times the rate in the general community.

This formed the basis for a much larger study, called ACT2, which aims to compare the diagnostic yield of ‘active’ screening of household contacts to the yield of ‘passive’ diagnosis obtained by routine practice. By June 2013, this randomised controlled trial enrolled 10,818 adult TB patients and 25,329 household contacts in 70 district TB clinics in eight provinces throughout the country. Contacts were screened four times over two years, using chest X-ray and symptom screening – with microbiological testing performed for contacts with suspected disease. The study was fully integrated within the NTP, with participant recruitment, screening and follow-up undertaken by government health care workers.

This study was registered as a clinical trial under number: ACTRN12610000600044