The guidance for using UVGI systems to kill or inactivate airborne TB bacteria is provided in the newly published Environmental Control for Tuberculosis: Basic Upper-Room Ultraviolet Germicidal Irradiation Guidelines for Health care Settings.
TB typically spreads from person to person as a direct result of breathing air contaminated with TB bacteria exhaled by an infectious person, often through coughing. Once airborne in a room, the bacteria may remain airborne and infectious for hours. Although TB cases have declined in the United States in recent years, the disease still endangers personnel in settings at high risk for exposure to persons with unsuspected or undiagnosed infectious TB, such as hospitals, nursing homes, outpatient clinics or correctional institutions.
"Tuberculosis is pernicious and insidious, an age-old illness that still poses risks to the dedicated health care workers on whom we depend for our health needs," said NIOSH Acting Director Christine M. Branche, Ph.D. "NIOSH is pleased to move this new research into practice to further strengthen the protective measures available to hospitals and other facilities."
The new guidance is consistent with and expands upon current guidelines by the Centers for Disease Control and Prevention (CDC) for reducing TB transmission in health care facilities. CDC recommends using administrative and environmental controls and personal respiratory protection, including ventilation as a primary environmental control.
Use of UVGI systems may help employers provide effective TB infection control in some facilities such as homeless centers and older hospitals, which may not have mechanical ventilation systems. UVGI systems also may aid employers and workers where ventilation systems are not designed to meet the recommended criteria, and retrofitting these systems may be difficult and expensive.
The system described in the guidance uses UVGI lamps in fixtures on or near the ceiling. The guidelines discuss factors influencing the effectiveness of UVGI, such as UVGI irradiance and dose, mechanical ventilation, air mixing, humidity and temperature. The guidelines also recommend consulting with a professional knowledgeable in upper-room UVGI systems and their installation before instituting the controls. These guidelines are practical, with sections focusing on how to select UV lamps and how to install and maintain the system.
Get more information on occupational prevention and control of TB.