Mass incarceration as a driver of the tuberculosis epidemic in Latin America and projected impacts of policy alternatives: A mathematical modeling study

Background Tuberculosis incidence is increasing in Latin America, where the incarcerated population has nearly quadrupled since 1990. The full impact of incarceration on the tuberculosis epidemic, accounting for effects beyond prisons, has never been quantified.

We calibrated dynamic compartmental transmission models to historical and contemporary data from Argentina, Brazil, Colombia, El Salvador, Mexico, and Peru, which comprise approximately 80% of the region’s incarcerated population and tuberculosis burden. Using historical counterfactual scenarios, we estimated the transmission population attributable fraction (tPAF) for incarceration and the excess population-level burden attributable to increasing incarceration prevalence since 1990. We additionally projected the impact of alternative incarceration policies on future population tuberculosis incidence. Findings Population tuberculosis incidence in 2019 was 29.4% (95% UI, 23.9-36.8) higher than expected without the rise in incarceration since 1990, corresponding to 34,393 (95% UI, 28,295-42,579) excess incident cases across countries. The incarceration tPAF in 2019 was 27.2% (95% UI, 20.9-35.8), exceeding estimates for other risk factors like HIV, alcohol use disorder, and undernutrition. Compared to a scenario where incarceration rates remain stable at current levels, a gradual 50% reduction in prison admissions and duration of incarceration by 2034 would reduce population tuberculosis incidence by over 10% in all countries except Mexico. Interpretation The historical rise in incarceration in Latin America has resulted in a large excess tuberculosis burden that has been under-recognized to-date. International health agencies, ministries of justice, and national tuberculosis programs should collaborate to address this health crisis with comprehensive strategies, including decarceration. Funding National Institutes of Health Evidence before this study We searched PubMed for studies on tuberculosis in prisons in Latin America, using the search terms (“tuberculosis”) AND (“prisons” OR “incarceration”) AND (“Latin America” OR “Argentina” OR “Brazil” OR “Colombia” OR “El Salvador” OR “Mexico” OR “Peru”), published in any language. Previous studies have identified a high risk of tuberculosis in prisons in Latin America, finding that notifications in prisons are increasing and account for a growing proportion of all cases in the region. Other national or sub-national studies have found elevated tuberculosis risk among formerly incarcerated individuals and transmission chains spanning prisons and communities. However, the full contribution of incarceration to the broader tuberculosis epidemic in Latin America—accounting for historical incarceration trends, under-detection in prisons, and “spillover” effects into communities—has never been quantified. Furthermore, previous studies have evaluated biomedical interventions in prisons; the regional impact of alternative incarceration policies on future population tuberculosis incidence is unknown. Added value of this study Here we quantify the full contribution of incarceration to the tuberculosis epidemic in Latin America. Our model captures the dynamic nature of incarceration, incorporating historical and contemporary data sources to account for varying prison turnover rates and mechanisms underlying historical incarceration growth. By modeling the population with incarceration history, we estimate the true size of the ever-exposed population, which across the six countries is over 11 times the size of the population within prison at any one time. We identify the settings where excess cases occur and compare our results to crude estimates based on notifications in prisons. We show, across six countries with diverse carceral contexts and tuberculosis epidemiology, that incarceration is a leading driver on par with other major tuberculosis risk factors, a role that has been under-recognized to date. Finally, we demonstrate the potential impact of alternative incarceration policies in reducing future tuberculosis burden in carceral settings and the general population. Implications of all the available evidence To date the true impact of incarceration on the tuberculosis epidemic across the region has been underestimated due to a narrow focus on disease occurring during incarceration. In light of the substantial excess tuberculosis burden attributable to incarceration, interventions targeting incarceration can have outsized effects on the broader tuberculosis epidemic in Latin America— much greater than previously appreciated. These interventions should include not only strategies to reduce tuberculosis risk among currently and formerly incarcerated individuals, but also efforts to end mass incarceration. Competing Interest Statement The authors have declared no competing interest. Funding Statement This study was funded by the National Institutes of Health (grant numbers 5R01AI130058 and 5R01AI149620). Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Footnotes Modifications made to methods, main text, and supplementary appendix in response to reviewers' comments. Co-author added (Prof. Marcelo Bergman). Data Availability Data and code for the present study have been deposited in the GitHub respository, tb_incarc_mod.