Contacts of underserved tuberculosis patients have higher odds of TB disease in North West England: a cohort study.

OBJECTIVE: To investigate the association between patients' social risk factors and the risk of tuberculous infection and TB disease among their contacts in England.

DESIGN: This was a cohort study of all TB cases from North West England diagnosed between 27 March 2012 and 28 June 2016. The social risk factors of TB cases were evaluated to estimate their need for enhanced case management (ECM), from 0 (standard of care) to 3 (intensive social support).

RESULTS: A total of 2139 cases and their 10 019 contacts met the eligibility criteria. Being a contact of a patient with smear-positive TB with high ECM or being of Black Caribbean ethnicity was independently associated with greater odds of active TB disease (smear-positive vs. smear-negative, OR 5.3, 95%CI 3.2-8.7; ECM-3 vs. ECM-0, OR 2.2, 95%CI 1.01-5.0; Black Caribbean vs. White, OR 7.4, 95%CI 2.1-25). Being a contact of a patient with smear-positive TB or of Black Caribbean ethnicity was also independently associated with greater odds of tuberculous infection (smear-positive vs. smear-negative, OR 5.3, 95%CI 3.8-7.3; and Black Caribbean vs. White, OR 6.7, 95%CI 2.0-25).

CONCLUSIONS: The social complexity and ethnicity of patients were associated with tuberculous infection and TB disease in their contacts.