In a tuberculosis screening and treatment initiative covering the entire population of Tibetan refugee schoolchildren in northern India, a team directed by researchers at Johns Hopkins Medicine and the University of Wisconsin says it has found not only a startlingly high prevalence of TB disease and infection, but also a potentially workable strategy to eliminate the disease in a large, high-risk group.
"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," says lead study author Kunchok Dorjee.
"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." Findings from the first year of the initiative were published in the journal Clinical Infectious Diseases.
Tibetan refugees in India have high rates of TB, and many children live in congregate settings such as boarding schools, say the researchers. For the study, program staff members first met with parents, educators and home mothers at boarding schools to gain their support. Then, they screened children in Tibetan schools class by class.
Using the schools' administrative records, the researchers ensured that every student and staff member was screened—they were screened for TB symptoms such as cough, fever and night sweats, and were interviewed about TB exposure history. Those presenting with TB symptoms were further evaluated using chest X-ray and laboratory testing. People with no prior history of TB also underwent tuberculin skin testing, a field-friendly screening tool that allows clinicians to diagnose TB infection by measuring immune response.
All those found to have active TB were treated with a standard six-month course of antibiotics, while those with drug-resistant TB received a prolonged course of combination drugs. A three-month course of daily preventive therapy (isoniazid and rifampicin) was provided to 799 of 930 (86%) schoolchildren and 101 of 334 (30%) staff members with TB infection. The Zero TB program paid for the study drugs, with support from the Johns Hopkins Center for Tuberculosis Research.
The program staff is now conducting follow-up examinations of schoolchildren and staff members every six months, Dorjee says. In 2018, the program was expanded to screen Tibetan refugees living in monasteries and nunneries in the region.
TB Case Finding
"Through comprehensive approaches that include TB case-finding, treatment and preventive therapy, TB control in high-burden settings is achievable," says the project's principal investigator Richard Chaisson.
After China invaded Tibet in the 1950s, many Tibetans fled to India and settled in exile in Dharamsala, now home to the Dalai Lama and the Tibetan central government, Dorjee explains. It is unknown whether the community previously had any immunity to TB, but exposure to the new environment in India, plus communal living in refugee areas and schools, and cold winter weather discouraging ventilation, provided a means for the infection to spread easily.
Approximately 1 million children worldwide develop tuberculosis and 250,000 die of the disease annually, the authors note. The average cost to treat the condition for a patient in the U.S. is $19,000 for drug-susceptible TB and $164,000 for multidrug-resistant TB. Globally, the average treatment cost is $1,224 for drug-susceptible TB and $7,141 for drug-resistant TB.