PREVALENCE OF LATENT TUBERCULOSIS AMONG HOUSEHOLD CONTACTS OF PATIENTS WITH MULTIDRUG‐RESISTANT TUBERCULOSIS IN VIETNAM

Background: Contacts of multidrug-resistant (MDR-TB) have a high risk of exposure to tuberculosis (TB), and are a high risk population for developing the disease.This study aimed to measure the prevalence of latent TB infection among household contacts of patients with MDR-TB.Methods: We undertook a cross-sectional survey among household members of patients with MDR-TB in Vietnam who agreed to be screened for participation in the VQUIN MDR trial.Household contacts were recruited from 132 clinics within the Programmatic Management of Drug Resistant TB (PMDT) program across 10 Provinces of the country.Eligible contacts of all ages had a clinical examination, chest radiograph and submitted one spontaneous sputum sample for Xpert MTB/RIF test to exclude active TB.LTBI status was established based upon a tuberculin skin test result of at least 10mm.Results: The overall prevalence of TST positivity was 2,383/3,494 (68.2%).The prevalence of TST positivity was similar between male and female contacts, and higher in adults.TST positivity increased with age and was associated with duration of exposure.Table 1 summarizes the prevalence of latent TB infection in this population.The prevalence of bacteriologically confirmed TB at screening was 46/2,383 (1.9%). Conclusion:The prevalence of LTBI was high among household contacts of patients with MDR-TB.Further research is required to evaluate the effect of medications to prevent progression to active disease among this high-risk population.