Latent tuberculous infection in household contacts of multidrugresistant and newly diagnosed tuberculosis
Prevalence of tuberculin skin test positivity in household contacts of patients with MDR-TB and never previously treated
Abstract
Background
Differences in the prevalence of latent tuberculous infection (LTBI) and tuberculosis (TB) disease among contacts of patients with multidrug-resistant TB (MDR-TB) and drug-susceptible TB are not well understood.
Objective
To compare the prevalence of tuberculin skin test (TST) positivity in household contacts of patients with MDR-TB and in contacts of patients never previously treated for TB (‘new TB’).
Design
Consecutive patients with MDR-TB and their household contacts at nine urban district clinics in Viet Nam were screened for TB and LTBI, and followed up for 6 months. LTBI was defined as a TST result of at least 10 mm.
Results
A total of 167 patients with TB and their 337 household contacts were recruited. A total of 167/180 (25.8%) contacts of new TB patients and 60/147 (40.8%) contacts of MDR-TB patients were TST-positive (odds ratio [OR] 2.0, 95%CI 1.3–3.2). Contacts of MDR-TB patients were more likely to have baseline chest radiograph findings consistent with TB (OR 2.6, 95%CI 1.4–5.0).
Conclusion
Contacts of MDR-TB patients have a high risk of developing TB. Measures to reduce Mycobacterium tuberculosis transmission and accelerate the detection of disease among high-risk contacts should be prioritised to curb the MDR-TB epidemic.
This research was supported by the UK Department for International Development’s Operational Research Capacity Building Programme led by the International Union Against TB and Lung Disease (The Union)
Citation
Fox GJ, Ahn NT, Nhung N V, Loi NT, Hoa NB, NgocAhn LT, Cuong NK, Buu TN, Marks GB, Menzies D. Latent Tuberculosis Infection in Household Contacts of Multidrug-resistant and Newly Diagnosed Tuberculosis. The International Journal of Tuberculosis and Lung Disease. 2017; 21(3):297–302.