CHARACTERIZATION OF INFECTIOUS AEROSOLS IN HEALTH-CARE FACILITIES - AN AID TO EFFECTIVE ENGINEERING CONTROLS AND PREVENTIVE STRATEGIES

Assessment of strategies for engineering controls for the prevention o f airborne infectious disease transmission to patients and to health c are and related workers requires consideration of the factors relevant to aerosol characterization. These factors include aerosol generation , particle sizes and concentrations, organism viability, infectivity a nd virulence, airflow and climate, and environmental sampling and anal ysis. The major focus on attention to engineering controls comes from recent increases in tuberculosis, particularly the multidrug-resistant varieties in the general hospital population, the severely immunocomp romised, and those in at-risk and confined environments such as prison s, long-term care facilities, and shelters For the homeless. Many work ers are in close contact with persons who have active, undiagnosed, or insufficiently treated tuberculosis. Additionally, patients and healt h care workers may be exposed to a variety of pathogenic human viruses , opportunistic fungi, and bacteria. This report therefore focuses on the nature of infectious aerosol transmission in an attempt to determi ne which factors can be systematically addressed to result in proven, applied engineering approaches to the control of infectious aerosols i n hospital and health care facility environments. The infectious aeros ols of consideration are those that are generated as particles of resp irable size by both human and environmental sources and that have the capability of remaining viable and airborne for extended periods in th e indoor environment. This definition precludes skin and mucous membra ne exposures occurring from splashes (rather than true aerosols) of bl ood or body fluids containing infectious disease agents. There are no epidemiologic or laboratory studies documenting the transmission of bl oodborne virus by way of aerosols.