Decline of Tuberculosis Burden in Vietnam Measured by Consecutive National Surveys, 2007–2017

Abstract

Vietnam, a high tuberculosis (TB) burden country, conducted national TB prevalence surveys in 2007 and 2017. In both surveys participants were screened by using a questionnaire and chest radiograph; sputum samples were then collected to test for Mycobacterium tuberculosis by smear microscopy and Löwenstein-Jensen culture. Culture-positive, smear-positive, and smear-negative TB cases were defined by laboratory results, and the prevalence of tuberculosis was compared between the 2 surveys. The results showed prevalence of culture-positive TB decreased by 37% (95% CI 11.5%–55.4%), from 199 (95% CI 160–248) cases/100,000 adults in 2007 to 125 (95% CI 98–159) cases/100,000 adults in 2017. Prevalence of smear-positive TB dropped by 53% (95% CI 27.0%–69.7%), from 99 (95% CI 78–125) cases/100,000 adults to 46 (95% CI 32–68) cases/100,000 adults; smear-negative TB showed no substantial decrease. Replacing microscopy with molecular methods for primary diagnostics might enhance diagnosis of pulmonary TB cases and further lower TB burden.

Social determinants of the changing tuberculosis prevalence in Việt Nam: Analysis of population-level cross-sectional studies

“…However, economic growth and reduction in poverty may not be the only explanation for the change, as there were also improvements in tuberculosis diagnostics and health service access through an expansion of health insurance in Vie ˙t Nam [19,20]. Possible explanations for the results of our study therefore include that the rapid economic development in Vie ˙t Nam led to tuberculosis patients being wealthier in the second survey.…”

“…The study found a 37% reduction in the prevalence of culture-positive tuberculosis, a 53% reduction in the prevalence of smear-positive tuberculosis, and no significant reduction in smear-negative or subclinical tuberculosis. The change in tuberculosis prevalence was more pronounced among men, among people living in rural areas, and in provinces in the north and south of the country [20].…”

“…Nationally representative Vie ˙t Nam tuberculosis prevalence surveys were conducted in 60 of 63 provinces in 2007 and 2017 [18,19]. A detailed explanation of the research procedures and differences between the 2 surveys are published elsewhere [20]. In summary, individuals were identified for inclusion in the surveys by multistage sampling whereby first districts and then communes were selected proportional to population size.…”

“…Individuals reporting a cough for at least 2 weeks, haemoptysis, or previous tuberculosis treatment, or who had an abnormal chest X-ray, were considered screen positive. In the first survey, 8.0% (7,529/94,156) of respondents screened positive, compared to 7.4% (4,595/ 61,763) in the second survey [20]. A flow diagram of participant selection is included in S1 Text.…”

“…National tuberculosis prevalence surveys were conducted in Vie ˙t Nam in 2007 and 2017 [18,19]. When differences in tuberculosis screening and diagnostic practices were accounted for, a comparative study showed a decline in tuberculosis prevalence over the 10-year period [20]. The study found a 37% reduction in the prevalence of culture-positive tuberculosis, a 53% reduction in the prevalence of smear-positive tuberculosis, and no significant reduction in smear-negative or subclinical tuberculosis.…”