Researchers report high rates of new TB infections among adolescents in Tanzania

Published today in PLOS ONE, “T-SPOT.TB Serial Responses in Tanzanian Adolescents: Transient, Persistent, and Irregular Conversions” [], researchers from Geisel School of Medicine and Muhimibili University of Health and Allied Sciences (MUHAS) report high rates of new tuberculosis (TB) infections among adolescents in Tanzania. Multiple blood tests for TB infection were carried out over three years in 650 school children aged 13 to 15 and showed that the risk of acquiring a new TB infection was 3% per year. Additionally, by performing six or more blood tests on each volunteer with an interferon gamma release test (IGRA), the study team identified novel transition patterns between positive and negative IGRA tests for IGRA. tuberculosis infection.

The data was obtained during the DAR-901 tuberculosis vaccine trial supported by the Global Health Innovative Technology Fund (GHIT, Tokyo), with additional support from Oxford Immunotec (Oxford, UK) and the Jack and Dorothy Byrne Foundation (New Hampshire).

Although not all TB infections lead to TB disease, at the population level this annual rate of infection is expected to lead to significant future rates of morbidity and mortality. This highlights the importance of developing TB control measures for this high-risk age group.”

Maryam Amour, MD, MPH ’15, Senior Author, Lecturer in the Department of Community Health at MUHAS

Christiaan Rees MED ’20, Guarini ’18, co-lead author and internal medicine resident at Brigham and Women’s Hospital in Boston, MA, who analyzed the trial data during her Geisel internship in Tanzania, says of study: “One of our novel findings was that the conversion of IGRA results to positive was usually not maintained; in fact, some participants converted to negative and then back to positive. This raises the possibility that we have seen TB infections that have been cleared.

The results demonstrate the feasibility of using the IGRA T-SPOT.TB test (Oxford Immunotec, UK) for serial screening of adolescents in school settings.

The principal investigator of the DAR-901 vaccine trial, Ford von Reyn, PhD, professor of medicine and director of international DarDar programs at Geisel, says the results suggest a possible new approach to finding TB cases. “Early TB infection is not associated with symptoms and is usually not detected until a skin test or IGRA blood test is done years later,” he says. “If you can test schoolchildren in a TB-endemic area every 3-6 months and identify the newly acquired infection, you have the opportunity to find and treat the person with symptomatic TB who infected the teenager and to reduce transmission.

The long-standing DarDar research and training partnership between the Geisel School of Medicine and MUHAS, established in 2001, has resulted in numerous clinical trials and sponsored numerous academic exchanges between the two institutions. More than 15 Tanzanian scientists have earned advanced degrees at Geisel under the NIH-sponsored NIH-sponsored MUHAS NIH Fogarty Training Fellowship at the University of Dartmouth-Boston. Additionally, through the Geisel Center for Health Equity, MUHAS students have participated in electives at Geisel, and many Geisel students and Dartmouth undergraduates have participated in electives in medicine and health care in Tanzania.


Journal reference:

Love, MA, et al. (2022) Serial T-SPOT.TB Responses in Tanzanian Adolescents: Transient, Persistent, and Irregular Conversions. PLOS ONE.


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