The prevalence of HIV, hepatitis B virus, hepatitis C virus, and tuberculosis are higher in prisons than in the general population in most countries worldwide. Prisons have emerged as a risk environment for these infections to be further concentrated, amplified, and then transmitted to the community after prisoners are released. In the absence of alternatives to incarceration, prisons and detention facilities could be leveraged to promote primary and secondary prevention strategies for these infections to improve prisoners health and reduce risk throughout incarceration and on release. Effective treatment of opioid use disorders with opioid agonist therapies (eg, methadone and buprenorphine) prevents blood-borne infections via reductions in injection in prison and after release. However, large gaps exist in the implementation of these strategies across all regions. Collaboration between the criminal justice and public health systems will be required for successful implementation of these strategies.

Despite global reductions in HIV incidence and mortality, the 15 UNAIDS-designated countries of Eastern Europe and Central Asia (EECA) that gained independence from the Soviet Union in 1991 constitute the only region where both continue to rise. HIV transmission in EECA is fuelled primarily by injection of opioids, with harsh criminalisation of drug use that has resulted in extraordinarily high levels of incarceration. Consequently, people who inject drugs, including those with HIV, hepatitis C virus, and tuberculosis, are concentrated within prisons. Evidence-based primary and secondary prevention of HIV using opioid agonist therapies such as methadone and buprenorphine is available in prisons in only a handful of EECA countries (methadone or buprenorphine in five countries and needle and syringe programmes in three countries), with none of them meeting recommended coverage levels. Similarly, antiretroviral therapy coverage, especially among people who inject drugs, is markedly under-scaled. Russia completely bans opioid agonist therapies and does not support needle and syringe programmes-with neither available in prisons-despite the country's high incarceration rate and having the largest burden of people with HIV who inject drugs in the region. Mathematical modelling for Ukraine suggests that high levels of incarceration in EECA countries facilitate HIV transmission among people who inject drugs, with 28-55% of all new HIV infections over the next 15 years predicted to be attributable to heightened HIV transmission risk among currently or previously incarcerated people who inject drugs. Scaling up of opioid agonist therapies within prisons and maintaining treatment after release would yield the greatest HIV transmission reduction in people who inject drugs. Additional analyses also suggest that at least 6% of all incident tuberculosis cases, and 75% of incident tuberculosis cases in people who inject drugs are due to incarceration. Interventions that reduce incarceration itself and effectively intervene with prisoners to screen, diagnose, and treat addiction and HIV, hepatitis C virus, and tuberculosis are urgently needed to stem the multiple overlapping epidemics concentrated in prisons.

The prison setting presents not only challenges, but also opportunities, for the prevention and treatment of HIV, viral hepatitis, and tuberculosis. We did a comprehensive literature search of data published between 2005 and 2015 to understand the global epidemiology of HIV, hepatitis C virus (HCV), hepatitis B virus (HBV), and tuberculosis in prisoners. We further modelled the contribution of imprisonment and the potential impact of prevention interventions on HIV transmission in this population. Of the estimated 10·2 million people incarcerated worldwide on any given day in 2014, we estimated that 3·8% have HIV (389 000 living with HIV), 15·1% have HCV (1 546 500), 4·8% have chronic HBV (491 500), and 2·8% have active tuberculosis (286 000). The few studies on incidence suggest that intraprison transmission is generally low, except for large-scale outbreaks. Our model indicates that decreasing the incarceration rate in people who inject drugs and providing opioid agonist therapy could reduce the burden of HIV in this population. The prevalence of HIV, HCV, HBV, and tuberculosis is higher in prison populations than in the general population, mainly because of the criminalisation of drug use and the detention of people who use drugs. The most effective way of controlling these infections in prisoners and the broader community is to reduce the incarceration of people who inject drugs.

The burden of HIV/AIDS and other transmissible diseases is higher in prison and jail settings than in the non-incarcerated communities that surround them. In this comprehensive review, we discuss available literature on the topic of clinical management of people infected with HIV, hepatitis B and C viruses, and tuberculosis in incarcerated settings in addition to co-occurrence of one or more of these infections. Methods such as screening practices and provision of treatment during detainment periods are reviewed to identify the effect of community-based treatment when returning inmates into the general population. Where data are available, we describe differences in the provision of medical care in the prison and jail settings of low-income and middle-income countries compared with high-income countries. Structural barriers impede the optimal delivery of clinical care for prisoners, and substance use, mental illness, and infectious disease further complicate the delivery of care. For prison health care to reach the standards of community-based health care, political will and financial investment are required from governmental, medical, and humanitarian organisations worldwide. In this review, we highlight challenges, gaps in knowledge, and priorities for future research to improve health-care in institutions for prisoners.

Given the dual epidemics of HIV and tuberculosis in sub-Saharan Africa and evidence suggesting a disproportionate burden of these diseases among detainees in the region, we aimed to investigate the epidemiology of HIV and tuberculosis in prison populations, describe services available and challenges to service delivery, and identify priority areas for programmatically relevant research in sub-Saharan African prisons. To this end, we reviewed literature on HIV and tuberculosis in sub-Saharan African prisons published between 2011 and 2015, and identified data from only 24 of the 49 countries in the region. Where data were available, they were frequently of poor quality and rarely nationally representative. Prevalence of HIV infection ranged from 2·3% to 34·9%, and of tuberculosis from 0·4 to 16·3%; detainees nearly always had a higher prevalence of both diseases than did the non-incarcerated population in the same country. We identified barriers to prevention, treatment, and care services in published work and through five case studies of prison health policies and services in Zambia, South Africa, Malawi, Nigeria, and Benin. These barriers included severe financial and human-resource limitations and fragmented referral systems that prevent continuity of care when detainees cycle into and out of prison, or move between prisons. These challenges are set against the backdrop of weak health and criminal-justice systems, high rates of pre-trial detention, and overcrowding. A few examples of promising practices exist, including routine voluntary testing for HIV and screening for tuberculosis upon entry to South African and the largest Zambian prisons, reforms to pre-trial detention in South Africa, integration of mental health services into a health package in selected Malawian prisons, and task sharing to include detainees in care provision through peer-educator programmes in Rwanda, Zimbabwe, Zambia, and South Africa. However, substantial additional investments are required throughout sub-Saharan Africa to develop country-level policy guidance, build human-resource capacity, and strengthen prison health systems to ensure universal access to HIV and tuberculsosis prevention, treatment, and care of a standard that meets international goals and human rights obligations.

Overweight and obesity are increasing worldwide. To help assess their relevance to mortality in different populations we conducted individual-participant data meta-analyses of prospective studies of body-mass index (BMI), limiting confounding and reverse causality by restricting analyses to never-smokers and excluding pre-existing disease and the first 5 years of follow-up.

Gay, bisexual, and other men who have sex with men (MSM) continue to have disproportionately high burdens of HIV infection in countries of low, middle, and high income in 2016. 4 years after publication of a Lancet Series on MSM and HIV, progress on reducing HIV incidence, expanding sustained access to treatment, and realising human rights gains for MSM remains markedly uneven and fraught with challenges. Incidence densities in MSM are unacceptably high in countries as diverse as China, Kenya, Thailand, the UK, and the USA, with substantial disparities observed in specific communities of MSM including young and minority populations. Although some settings have achieved sufficient coverage of treatment, pre-exposure prophylaxis (PrEP), and human rights protections for sexual and gender minorities to change the trajectory of the HIV epidemic in MSM, these are exceptions. The roll-out of PrEP has been notably slow and coverage nowhere near what will be required for full use of this new preventive approach. Despite progress on issues such as marriage equality and decriminalisation of same-sex behaviour in some countries, there has been a marked increase in anti-gay legislation in many countries, including Nigeria, Russia, and The Gambia. The global epidemic of HIV in MSM is ongoing, and global efforts to address it remain insufficient. This must change if we are ever to truly achieve an AIDS-free generation.