US mass incarceration promotes spread, says Boston University School of Public Health

In 2019, people incarcerated worldwide are almost ten times more likely to contract tuberculosis (TB) than the general population, a study by the Boston University School of Public Health (https://www.bu.edu/sph) shows. This is the first worldwide scientific study in the field. It shows persistently high numbers of cases and only a low number of detections of the disease. In 2019, 125,105 of the world’s 11 million incarcerated people contracted TB. This equates to 1,148 cases per 100,000 people per year. Despite these high case numbers, almost half of TB cases in prisons go undiagnosed, according to the study.

Africa most affected

According to corresponding author Leonardo Martinez, only 53 per cent of people with TB in prisons receive a diagnosis. “This suggests that these detainees are neglected and have minimal medical facilities for diagnosis.” The researchers analysed extensive data from published studies and official sources. The aim was to examine the prevalence and incidence of TB in 193 counties (districts) at regional and global levels – from 2000 to 2019. The team additionally examined the proportion of TB cases detected per year for each county.

In 2019, Africa had the highest number of new cases. This figure was 2,242 cases per 100,000 people per year. However, North, Central and South America had the largest number of total cases. It increased by 90 per cent since 2000. In 2019, Brazil, Russia, China, the Philippines and Thailand were the most affected. Yet the number of new cases remained constant between 2012 and 2019, with values between 1,100 and 1,200 people per year. According to C. Robert Horsburgh, this stagnation indicates that current control policies in prisons are not working to reduce the burden of tuberculosis and that further action is needed.

Problem of mass incarceration

According to Martinez, mass incarceration is a major cause of TB transmission. Occupancies of up to 30 people in a cell cause the disease to spread like wildfire. Contrary to popular belief, incarcerated people are very mobile. “In many countries, the length of stay in prison is very short. People who contract the disease while in prison then transmit it to the general population. As almost half of those affected are not appropriately diagnosed in hospital, many people remain infectious after imprisonment.” Details were published in “The Lancet Public Health”.