Active case-finding in contacts of people with TB

BACKGROUND: Exposure to people with TB substantially elevates a person's risk of tuberculous infection and TB disease. Systematic screening of TB contacts enables the early detection and treatment of co-prevalent disease, and the opportunity to prevent future TB disease. However, scale-up of contact investigation in high TB transmission settings remains limited.METHODS: We undertook a narrative review to evaluate the evidence for contact investigation and identify strategies that TB programmes may consider when introducing contact investigation and management.RESULTS: Selection of contacts for priority screening depends upon their proximity and duration of exposure, along with their susceptibility to develop TB. Screening algorithms can be tailored to the target population, the availability of diagnostic tests and preventive therapy, and healthcare worker expertise. Contact investigation may be performed in the household or at communal locations. Local contact investigation policies should support vulnerable patients, and ensure that drop-out during screening can be mitigated. Ethical issues should be anticipated and addressed in each setting.CONCLUSION: Contact investigation is an important strategy for TB elimination. While its epidemiological impact will be greatest in lower-transmission settings, the early detection and prevention of TB have important benefits for contacts and their communities.