Prevalence of latent tuberculous infection among adults in the general population of Ca Mau, Viet Nam

SETTING: The study was conducted in a randomly selected sample of persons aged >= 15 years living in Ca Mau Province, southern Viet Nam. OBJECTIVE : To estimate the prevalence of latent tuberculous infection (LTBI) in the general adult population of this province of Viet Nam. The secondary objective was to examine age and sex differences in prevalence. DESIGN: A cross-sectional survey was conducted in a cluster-random sample of the population. Clusters were subcommunes. The presence of LTBI was assessed using the QuantiFERON (R)-TB Gold In-Tube test system. RESULTS : QuantiFERON tests were performed among 1319 persons aged >= 15 years (77.7% of those selected). The overall prevalence of positive tests was 36.8% (95% CI 33.4-40.3). The prevalence of a positive test was lower in females than in males (31.0% vs. 44.7%, OR 0.57, 95% CI 0.45-0.72, P< 0.0001). The prevalence of positive tests increased with increasing age quintile (P< 0.0001). CONCLUSION: More than one third of the general adult population in a province in southern Viet Nam have evidence of LTBI. Although LTBI prevalence is higher in males, the sex difference is not as great as that for TB notification rates.