Contact tracing for tuberculosis, Thailand.

Problem: Despite implementation of universal health coverage in Thailand, gaps remain in the system for screening contacts of tuberculosis patients.

Approach: We designed broader criteria for contact investigation and new screening practices and assessed the approach in a programme-based operational research study in 2017-2018. Clinic staff interviewed 100 index patients and asked them to give household and non-household contacts an invitation for a free screening and chest X-ray. Contact persons who attended received 250 Thai baht (about 8 United States dollars) allowance for transport.

Local Setting: Chiang Rai province, Thailand, has high rates of tuberculosis notification and a high number of people living in poverty. The coverage of contact investigation in under 5-year-olds was only 33.2% (222 screened out of 668 contacts) over 2011-2015.

Relevant Changes: Index patients identified 440 contacts in total and gave invitation cards to 227 of them. The contact investigation coverage was 81.1% (184/227) and tuberculosis detection among contacts screened was 6.0% (11/184). Of the 11 contacts with active tuberculosis, three did not have tuberculosis symptoms, three were non-household contacts and three were contacts of non-smear-positive tuberculosis patients. The contact investigation coverage of the contacts younger than 5 years was 100% (14/14) and the yield of tuberculosis detection in this age group was 21.4% (3/14).

Lessons Learnt: High coverage of contact investigation with a high yield of tuberculosis detection among contacts can be achieved by applying broader criteria for contact investigation and providing financial support for transportation.