For the first time ever researchers have estimated the rate of tuberculosis (TB) in incarcerated persons, having analysed data from almost every country in the world (193 out of 195 countries) between 2000 and 2019. The findings will be published in The Lancet Public Health on 29 June, 23.30 UK time.

Approximately 125,105 of the 11 million people incarcerated globally developed TB in 2019 – a rate of 1,148 cases per 100,000 people per year. Significantly higher than the global incidence rate among all persons – 127 cases per 100,000 people per year.

However, the case detection rate was just 53% of all TB cases in prisons globally. Furthermore, the researchers found a strong relationship between country-level tuberculosis incidence rates and overcrowding in prisons

Leonardo Martinez, study lead from School of Public Health, Boston University, USA, said: “This connection between TB and overcrowding suggests that efforts to limit the number of people who are detained may be one potential public health tool to combat the TB epidemic in prisons.”

The elevated risk of TB among incarcerated populations exceeds that of diabetes, alcohol use disorders, smoking and undernourishment.

The study team, consisting of researchers from across the world, identified that prison TB rates varied greatly by World Health Organization (WHO) region in 2019, with:

• The greatest incidence rate in the African region – 2,242 cases 100,000 people per year – almost double the global estimate for this population
• The Americas region, largely driven by Central and South America, had the largest estimated absolute number of TB cases among incarcerated persons – 30,509

Anthony D Harries, senior adviser at the International Union Against Tuberculosis and Lung Disease, said: “These findings give us a much clearer picture of tuberculosis in prisons than we’ve ever had before. The high rate of tuberculosis and low rate of detection indicates that current control measures are insufficient for preventing the spread of the disease in prisons globally. Therefore, further research is vital to identify and implement the most effective interventions.”

Martinez concluded: “The high incidence rate globally and across regions, low case detection rates, and consistency over time indicate that this population represents an important, under-prioritised group. Continued failure to detect, treat, and prevent tuberculosis in prisons will result in the unnecessary disease and deaths of many incarcerated persons. And, of course, when incarcerated persons are released from prison they can take this infectious disease back into the communities in which they live, further contributing to the spread of tuberculosis globally. Greater focus and resources for addressing the tuberculosis epidemic in prisons are needed to protect the health of incarcerated people and their communities.”

Karabo Rafube, who developed TB in a South African prison, said: “There was no screening when you entered and we were crowded into small spaces, so it was no surprise that I caught TB. I was very sick, but it took a long time to find out that I had TB. I took treatment for six months and luckily full recovered. Some people would sell their medicines to other inmates.

“After recovering I was appointed as a TB teacher in the prison. Ever since I left, I’ve been supporting others with TB in prison.

“It is important to break the silence of TB. Prisoners have the right to be screened and have access to medicines, but they are often neglected. We can’t end TB without treating everyone – that includes prisoners.”

The International Union Against Tuberculosis and Lung Disease (The Union) officially sponsored the four-year project, providing TB research expertise, logistical and operational support and accountability for success.

Further regional prison differences

There were important differences by WHO region over time. Incidence decreased in several regions (e.g., European, African, and South-East Asian regions) and increased in the Americas region.
Trends in Europe were largely influenced by prisons in Russia which, after targeted interventions in prisons and reductions in incarceration over the past decade, have successfully reduced TB incidence in prisons.

Reasons for the increases in TB burden in the Americas may be multifactorial. Mass incarceration has risen dramatically in the Americas likely leading to increased crowding. The strong association found between crowding and TB incidence suggests this may be an important driver of the rising TB incidence in prisons from the Americas, especially in Central and South America.

While estimated incidence rates were high across WHO regions, there were differences within regions as well. For example, in the Americas, incidence in South and Central American countries (both more than 1,200 cases per 100,000 people per year) was considerably higher than those in North America (less than 50 incident cases per 100,000 people per year). Similarly, eastern Europe had a substantially higher incidence than western Europe.