III. Methods for Worker Protection—Controlling Airborne Transmission of Tuberculosis
A. Previous Recommendations for Personal Respiratory Protection—The existing CDC guidelines include extensive recommendations regarding the use of respirators in certain higher-risk areas for preventing the transmission of tuberculosis in health-care settings (10). These recommendations include in part:
[Section II.D.2.c.] For persons exposed to tuberculosis patients. Appropriate masks, when worn by health-care providers or other persons who must share air space with a patient who has infectious tuberculosis, may provide additional protection against tuberculosis transmission. Standard surgical masks may not be effective in preventing inhalation of droplet nuclei (46), because some are not designed to provide a tight face seal and to filter out particulates in the droplet nucleus size range (1-5 microns). A better alternative is the disposable PR [NIOSH-certified, particulate respirator]. PRs were originally developed for industrial use to protect workers. Although the appearance and comfort of PRS may be similar to that of cup-shaped surgical masks, they provide a better facial fit and better filtration capability. However, the efficacy of PRS in protecting susceptible persons from infection with tuberculosis has not been demonstrated.
A reexamination by NIOSH of the role of personal respiratory protection, especially the particulate respirator, in protecting health-care-facility workers against tuberculosis infection transmitted in health-care settings is presented in the next section.
B. The "Hierarchy of Controls"—Prudent occupational health practice calls for application of a hierarchy of controls to any occupational health hazard (47,48,49,50). The control hierarchy is long-standing and has wide-spread acceptance in the occupational-health community because it is based on broad practical experience, and scientific and technical logic (51).
NIOSH has supported the necessity of an ordered approach to evaluating a series or combination of effective control strategies to protect workers (47). The Institute has recommended the following essential characteristics of specific control solutions (47):
