What will it take to control TB in South African prisons?

In 1903 the New York Times claimed that sending people to jail condemned prisoners both to hard labour and tuberculosis (TB) infection. Approximately 40-60% of all jail deaths at the time were due to TB, and most autopsy findings showed evidence of infection with the TB bacillus, Mycobacterium tuberculosis.

Over a century later, TB is the leading cause of morbidity and mortality in South African prisons. TB in our correctional facilities can be transmitted to the general population via prison workers or inmates released back into the community. Correctional facilities are thought to be responsible for 3-17% of active cases of the disease in the general population.

Tuberculosis is spread by infectious particles breathed out from the lungs of infected people. These bacilli remain airborne long enough to be breathed in by others and gain access to the deeper parts of their lungs. In susceptible people – those whose immune systems are unable to fight off the infection – these particles may cause further cases of active TB.

TB spreads easily in prisons because inmates with active TB are confined together with other inmates who may be susceptible to infection. The risk of transmission for those in jail depends therefore on the prevalence of active TB and the amount of air exchanged between prisoners.

Inmates are specifically identified in the ‘National Strategic Plan for HIV, TB and STIs 2012 – 2016’ as a key population in the management of TB. The existing TB control programme calls on the Department of Correctional Services (DCS) to identify infectious cases both when prisoners are admitted and during the period of their incarceration. The programme also specifies what therapy is effective for treating inmates with TB.

The treatment of active TB is highly beneficial. It can decrease the prevalence of cases and help to reduce the quantity of contaminated air in prisons. Four factors determine the efficiency of TB transmission and the amount of air shared between inmates: the number of prisoners per cell, the length of the lock-up time, how much external uncontaminated air is used for ventilation, and the separation of potentially infectious cases from the wider prison population.

To control TB in our prisons, the DCS must address both the prevalence of TB and help to reduce the transmission efficiency of the disease. Overcrowding and poor ventilation in our jails are boosting the efficiency of TB transmission to such an extent that even regular screening and well-run control programmes would fail to keep the disease in check.

Improving physical conditions without reducing TB prevalence will not contain the spread of infection in our prisons. But providing effective identification and treatment, implementing South Africa’s prison crowding regulations, and providing moderate ventilation could decrease TB transmission by 40% or more. The introduction of prisoner lock-up periods not longer than 14 hours at a time, and the implementation of internationally recommended standards for space and cell ventilation could decrease TB transmission by 80%.

If a strategy of stronger TB control and environmental improvements is introduced in our prisons, the challenge would then be to create measurable targets for each key component. TB treatment is monitored for success and completion rates but as yet there is no measurement available to determine the efficacy of screening. The proportion of the prison population screened using sensitive TB diagnostics such as the GeneXpert testing system would be a useful interim way to assess this.

Cell ventilation is a difficult parameter to measure. However, it is easy to gauge carbon dioxide levels within cells. Doing so could help to quantify the amount of ventilation per cell occupant. Maintaining carbon dioxide levels below 1,500 parts per million would ensure that prisoners who are confined for long periods would have high ventilation standards similar to those recommended for schools and work environments.

TB is out of control in our prison system. Its spread has been aided by environmental conditions that fall far short of international standards – even those developed during the apartheid era. We need a fresh strategic approach incorporating better TB diagnosis and care together with improvement in South Africa’s appalling conditions of incarceration. Monitoring this new combined approach will require the DCS to introduce scientifically-determined targets for identifying cases and to provide minimum levels of ventilation.

Professor Robin Wood, Director, Desmond Tutu HIV Centre