Half of tuberculosis cases in prisons worldwide go unnoticed

 Researchers found consistently high TB case rates and low case detection in prisons, suggesting the need for health organizations to increase efforts to reduce the spread of TB among this high-risk population.

According to a new study led by the Boston University School of Public Health (BUSPH), incarcerated people worldwide developed tuberculosis (TB) at nearly ten times the rate of the general population in 2019.

According to the study, which was published in The Lancet Public Health, 125,105 of the 11 million people incarcerated worldwide developed tuberculosis in 2019, a rate of 1,148 cases per 100,000 people per year.

Despite this high case rate, nearly half of all tuberculosis cases among incarcerated people were missed.

The findings provide the first global and regional estimates of new tuberculosis cases among incarcerated people, a population at high risk of contracting this potentially fatal disease. The high case rate and low detection rate highlight the need for increased awareness and resources to reduce the burden of tuberculosis in prisons and other high-risk settings.

"Our study showed that only 53 per cent of people that develop tuberculosis in prisons are diagnosed, which suggests that incarcerated people are neglected and have minimal healthcare services to diagnose tuberculosis," said study lead and corresponding author Dr Leonardo Martinez, assistant professor of epidemiology at BUSPH.

To better understand TB rates among this population, Dr Martinez and colleagues acquired data from published research and from countries' federal officials to analyze TB prevalence and incidence in 193 countries at the country, regional, and global levels between 2000-2019. The team also calculated TB case detection rates per year in each country for 193 countries.

The African region had the highest rate of new TB cases in 2019, at 2,242 cases per 100,000 persons per year, but the Americas region--largely driven by Central and South America--had the greatest number of total cases, which increased nearly 90 per cent since 2000. The countries with the highest number of new cases in prisons in 2019 were Brazil, Russia, China, the Philippines, and Thailand.

Notably, the team found that new TB case rates remained between 1,100 and 1,200 cases per 100,000 persons per year from 2012-2019.

"This stagnation suggests that current tuberculosis control policy in prisons is insufficient to decrease the tuberculosis burden and that supplementary interventions and policy implementation are needed," said Dr C. Robert Horsburgh, professor of global health at BUSPH.

Mass incarceration is one major driver of TB transmission--both inside and outside of prisons. Overcrowding, where some prison cells contain up to 30 people, causes TB to "spread like wildfire," Dr Martinez said, and this transmission can spill over easily into the community.

"Contrary to popular belief, persons that are incarcerated are a mobile population, and in many countries, the duration of incarceration is very short," he said. "People go into prison, then come out, then may go back in again. So, very often, people that develop tuberculosis in prison end up transmitting the disease to many people outside of prison once they are released. Since almost half of the people with tuberculosis in prisons are not diagnosed, many still remain infectious when they enter back into the general community."

The team hopes that these findings will encourage global and regional health organizations to develop routine monitoring of TB among incarcerated people, as they do for other high-risk populations such as people with HIV and household contacts. The researchers say that their comprehensive compilation of TB case notifications--which they retrieved directly from federal officials, national and regional organizations, and non-governmental organizations--is a clear indication that information about TB in prisons is both accessible and retrievable by global organizations such as the health-organization">World Health Organization.

The team is currently working with several health organizations to attempt to update global guidelines on how to manage and reduce TB in prisons, as the most recent guidelines were written in the year 2000.

"One of the reasons this population is so neglected is because of the lack of data," Dr. Martinez said. "Our hope is that these results can help stakeholders understand the urgency of the issue and the number of people in prisons that develop tuberculosis and remain undiagnosed for long periods of time and can spur them to take action."