Almost 1 in 5 Tibetan schoolchildren have TB infection

Richard Chaisson

Nearly 20% of Tibetan schoolchildren have latent tuberculosis, according to results of a study that included all Tibetan refugee schoolchildren residing in northern India. Researchers also observed that more than half of school staff have TB infection.

A TB screening and treatment program allowed the researchers to provide most of the children who tested positive for TB with preventive therapy for 3 months, with nearly all participants completing the regimen.

“Our innovative initiative includes population-level implementation of TB preventive therapy as part of a multipronged strategy to control and eliminate TB in an at-risk population in India,” Kunchok Dorjee, PhD, MBBS, a research associate at the Johns Hopkins University School of Medicine and director of the Zero TB in Tibetan Kids project, said in a press release. “With the support of local leadership and community mobilization, including support from His Holiness the Dalai Lama, we have demonstrated that TB control can be achieved on a population level. The findings provide a benchmark to measure and compare progress toward elimination in the future.”

Dorjee and colleagues screened the schoolchildren for TB between April 2017 and March 2018. The screening algorithm included symptom criteria, chest X-rays, molecular diagnostics and tuberculin skin tests (TSTs). Children and staff with active TB were treated, and those without active TB but who had a positive TST received 3 months of preventive isoniazid-rifampicin therapy.

During the study, 5,391 schoolchildren and 786 staff at seven boarding schools and four day schools were screened. Dorjee and colleagues identified 46 cases of active TB disease in schoolchildren, including one multidrug-resistant case — a prevalence of 853 per 100,000. One staff member was diagnosed with extensively drug-resistant TB.

According to the researchers, 66% of cases were subclinical, and latent infection was identified in 18% of schoolchildren and 53% of staff who completed testing. Globally, the prevalence of childhood TB is estimated to be one in 28, according to a 2014 study published in The Lancet Global Health.

In the current study, children in boarding schools had a higher prevalence of TB than children in day schools (18% vs. 4%).

Preventive therapy was given to 86% of children and only 30% of staff. The researchers said the reason for the comparatively low uptake of preventive therapy among staff might have been “the program's emphasis on children, as well as the older age and a lower perception of risk of staff and the absence of standard guidelines for treating older contacts of cases in global TB guidelines.” Almost everyone (95%) completed therapy, the researchers added.

“Through comprehensive approaches that include TB case-finding, treatment and preventive therapy, TB control in high-burden settings is achievable,” Richard Chaisson, MD, professor of medicine at the Johns Hopkins University School of Medicine and director of the Johns Hopkins Center for Tuberculosis Research, said in the release. – by Katherine Bortz

References:

Dodd PJ, et al. Lancet Glob Health. 2014;doi:10.1016/S2214-109X(14)70245-1.

Dorjee K, et al. Clin Infect Dis. 2018;doi:10.1093/cid/ciy987/5193441.

Disclosures: Dorjee reports no relevant financial disclosures. Please see the study for other authors’ relevant financial disclosures.

Editor's note: The article has been updated to indicate that almost 20% of the schoolchildren had latent, not active, TB infection. The editors regret the error.