Tuberculosis in health care settings and the estimated benefits of engineering controls and respiratory protection.
Intra-institutional spread of tuberculosis (Tb) has re-emerged as a substantial public and occupational health threat. To characterize the person-hours and lifetime risks of Tb-related morbidity and mortality, we performed a risk assessment for health care workers (HCWs) developing Tb-related morbidity and mortality at varying levels of exposure, engineering controls, and respiratory protection. Under average conditions of exposure, one Tb skin-test conversion is estimated to occur for every 2650 person-hours of work by unprotected workers. With higher exposures, a skin-test conversion for an unprotected worker may occur in as few as 3 person-hours. Use of respiratory protection is estimated to reduce risks by the following proportions: surgical mask, 2.4-fold; disposable dust, fume, mist, or disposable high-efficiency particulate air filtering (HEPA) mask, 17.5-fold; elastomeric HEPA cartridge respirator, 45.5-fold; or powered air-purifying respirator (PAPR), 238-fold. Assuming a lifetime exposure of 250 hours, the risk of a skin-test conversion is estimated to be 9%. We conclude that HCWs are at substantial risk for Tb-related morbidity and mortality, and that administrative controls, engineering controls, and respirators offer substantial benefits in risk reduction.
Barnhart
S
S
Department of Medicine, University of Washington, Seattle 98104-2499, USA.
Sheppard
L
L
Beaudet
N
N
Stover
B
B
Balmes
J
J
D006801:Humans; D017053:Infection Control / Q000379:methods*; D017758:Infectious Disease Transmission, Patient-to-Professional / Q000517:prevention & control*; D008397:Masks; D008962:Models, Theoretical; D016012:Poisson Distribution; D012134:Respiratory Protective Devices; D018570:Risk Assessment; D014374:Tuberculin Test; D014376:Tuberculosis / Q000517:prevention & control* / Q000635:transmission; D014466:Ultraviolet Rays; D014691:Ventilation / Q000379:methods