Tuberculosis among health-care workers in low- and middle-income countries: a systematic review

Abstract

Background: The risk of transmission of Mycobacterium tuberculosis from patients to health-care workers (HCWs) is a neglected problem in many low- and middle-income countries (LMICs). Most health-care facilities in these countries lack resources to prevent nosocomial transmission of tuberculosis (TB).

Methods and findings: We conducted a systematic review to summarize the evidence on the incidence and prevalence of latent TB infection (LTBI) and disease among HCWs in LMICs, and to evaluate the impact of various preventive strategies that have been attempted. To identify relevant studies, we searched electronic databases and journals, and contacted experts in the field. We identified 42 articles, consisting of 51 studies, and extracted data on incidence, prevalence, and risk factors for LTBI and disease among HCWs. The prevalence of LTBI among HCWs was, on average, 54% (range 33% to 79%). Estimates of the annual risk of LTBI ranged from 0.5% to 14.3%, and the annual incidence of TB disease in HCWs ranged from 69 to 5,780 per 100,000. The attributable risk for TB disease in HCWs, compared to the risk in the general population, ranged from 25 to 5,361 per 100,000 per year. A higher risk of acquiring TB disease was associated with certain work locations (inpatient TB facility, laboratory, internal medicine, and emergency facilities) and occupational categories (radiology technicians, patient attendants, nurses, ward attendants, paramedics, and clinical officers).

Conclusions: In summary, our review demonstrates that TB is a significant occupational problem among HCWs in LMICs. Available evidence reinforces the need to design and implement simple, effective, and affordable TB infection-control programs in health-care facilities in these countries.

Figure 1. Study Flow Chart

Figure 2. Prevalence of TB Infection in HCWs as Determined by TST Surveys

The circles and the lines represent the point estimates and 95% CIs, respectively. The size of the circle indicates the study size, and the diamond indicates the pooled estimate (weighted average) and its 95% CI. The heterogeneity chi-square statistics are 142.6 (p < 0.01) for the medical students and 600.9 (p < 0.01), for all HCWs, indicating significant heterogeneity across studies. (a) Indicates estimate of TST positivity in nursing students at entry into nursing school. (b) Indicates estimate of TST positivity after 3 y in nursing school.

Figure 3. A Young Medical Trainee Examines a Patient with Pulmonary TB at a Rural Hospital in India

In such low-income countries, more years of clinical training and greater exposure to TB patients are important risk factors for acquiring new TB infection.