Tuberculosis (TB) is an infectious disease that affects more than 2 billion people worldwide. Because infection is passed in the air between people, it is important to test people who have been in close contact with a person who has the disease. These people are tested to see if they either have signs of infection or have active TB disease. Looking for people who might have been infected is termed TB contact tracing.

This study carried out a search for research on ways to carry out contact tracing. We aimed to bring together the findings of different studies. We wanted to find out the best ways to trace contacts. Because certain groups of people (such as homeless people or people who use drugs) are at higher risk of getting TB, we wanted to know what might work well for them.

We found 112 research papers or reports that were relevant to our study. The research mostly described contact investigations, and counted the number of people who were tested. This does not tell us how effective contact tracing is, as different people with TB will have different numbers of contacts. It was therefore difficult to get a clear understanding of what works best. The research highlighted that investigating places where infected people go is important. In addition, the traditional method of asking people to give names of contacts has limitations (especially for people at greater risk). The research also emphasised the importance of local resources, staff skills, systems for managing data and services working effectively together.