TUBERCULOSIS TRANSMISSION IN A SOUTH AFRICAN PRISON

1. TUBERCULOSIS TRANSMISSION IN A SOUTH AFRICAN PRISON Robin Wood Desmond Tutu HIV Centre Institute of Infectious Disease & Molecular Medicine University of Cape Town

2. NEW YORK 1903 The average prison is no less than a tubercular death trap.. from forty to sixty per cent, of all the deaths in prison are due to tuberculosis and autopsies show that nearly all the prisoners have in some degree been infected!” Dr. J. B. Ransom, of Clinton Prison, New York

3. The median estimated annual incidence rate ratio (IRR) for LTBI and TB were26.4(interquartile range [IQR]: 13.0–61.8) and 23.0 (IQR: 11.7–36.1), respectively. The median estimated fraction (PAF%) of tuberculosis in the general population attributable to the exposure in prisons for TB was 8.5% (IQR: 1.9%–17.9%) and 6.3% (IQR: 2.7%–17.2%) in high- and middle/low-income countries, respectively. These findings suggest that the risk of LTBI and TB is at least an order of magnitude higher in prisons than in the general population and that the within-prison spread of LTBI and TB is likely to substantially affect the incidence of LTBI and TB in the general population. December 2010 | Volume 7 | Issue 12 | e1000381

4. CURRENT WHO RECOMMENDATIONS The priority strategy must be the widespread implementation of the Stop TB Strategy, particularly addressing TB/HIV co-infection and MDR-TB, in the incarcerated population. Every prisoner should have unrestricted access to the correct diagnosis and treatment of TB. Delays in the detection and treatment of TB cases must be minimized to reduce further transmission of infection and pressures to self-treat TB. Unregulated, erratic treatment of TB in prisons should cease. Urgent action is needed to integrate prison and civilian TB services to ensure treatment completion for prisoners released during treatment. Measures to reduce overcrowding and to improve living conditions for all prisoners should be implemented to reduce transmission of TB

5. TB TRANSMISSION Quantity of exhaled air rebreathed Concentration of TB particles Infectious TB case Susceptible individual

6. TB INFECTION RISK IN PRISONS Probabilityof TB infection Quantity of rebreathed air Concentration of TBorganisms Cell crowding Lock-up time Cell ventilation No of TB cases Infectivity Period of infectivity=Δ

7. Pollsmoor prison has 3,200 awaiting trial prisoners Space allocation: 1,4 m2 per prisoner Lock-up time 23 hours per day SAMJ 2011;101(11):809-13

8. CROWDING & TB TRANSMISSION Space allocation: 1,4 m2 per prisoner Current 1.4m2 RSA 3.4m2 WHO 5.4m2 Fig. 1. The effect of prison cell overcrowding on TB transmission probabilities is plotted against time periods of infectiousness up to 180 days. They are shown for 3 levels of overcrowding; 250% approximates the current level cell occupancy; 100% represents implementation of current South African statutory minimum occupancy of 3.44 m2 of floor space per inmate,7-10 and 50% corresponds to international space recommendations. SAMJ 2011;101(11):809-13

9. LOCK-UP TIME & TB TRANSMISSION Fig. 2. The effect of length of period of restriction in prison cell per day on TB transmission probabilities is plotted against time periods of infectiousness up to 180 days, shown for 3 time periods of cell occupancy during a 24-hour period; 23 hours per day, 12 hours per day and 8 hours per day. NB: 23 hours per day is the current period of restriction to cells in Pollsmoor prison. SAMJ 2011;101(11):809-13

10. CELL VENTILATION

11. CELL VENTILATION & TB TRANSMISSION Fig. 3. The effect of increasing levels of cell ventilation on TB transmission probabilities is plotted against time periods of infectiousness up to 180 days. They are shown for 4 values of ventilation air change per hour (ACH): 1 ACH (current estimated cell ventilation), 3 ACH (minimal international recommendation), 8 ACH (moderately increased ventilation) and 12 ACH (the optimal level of ventilation recommended by WHO for health care set- tings). SAMJ 2011;101(11):809-13

12. COMBINED TB CONTROL MEASURES Fig. 2. The effect of length of period of restriction in prison cell per day on TB transmission probabilities is plotted against time periods of infectiousness up to 180 days, shown for 3 time periods of cell occupancy during a 24-hour period; 23 hours per day, 12 hours per day and 8 hours per day. NB: 23 hours per day is the current period of restriction to cells in Pollsmoor prison. SAMJ 2011;101(11):809-13

13. PRISON CELL CO2 LEVELS > 5000ppm (SABS 1040) Regulatory CO2 Exposure Limits • ASHRAE Standard 62-1989 1000ppm • CO2 concentration in occupied buildings should not exceed 1000ppm • Building bulletin 101 (BB101) 1500ppm • UK standard for schools, average CO2 during day should not exceed 1500ppm • EPA Taiwan 1000ppm and 600ppm • Type-1: Stores, theaters, restaurants, & libraries the 8hour average CO2 should not exceed 1000ppm • Type 2: Special areas e.g. schools, hospital, day care centers recommend 600ppm

14. The average prison is no less than a tubercular death trap. Dr. J. B. Ransom 1903

15. TUBERCULOSIS CONTROL IN PRISONS • Decrease TB disease prevalence • Effective TB case management • Active case finding at entry and subsequently • Rapid diagnostics • Reduce overcrowding • Communal cells are a disaster! • Lock up times too long! • Ventilation • Use appropriate building codes • Maintain cross cell air flow • Ventilation monitored by CO2