NIOSH Offers New Technical Guidance for Using UV Systems To Help Protect Healthcare Workers from TB Infection Risk

Contact: Rebecca Mao (202) 245-0647
March 31, 2009

The National Institute for Occupational Safety and Health (NIOSH) offers new technical guidance for using ultraviolet germicidal irradiation (UVGI) systems to help protect healthcare workers who may have an occupational risk of tuberculosis (TB) infection.

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 Healthcare Settings. The document is available at the NIOSH website http://www.cdc.gov/niosh/docs/2009-105/

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, TB bacteria may remain airborne and infectious for hours. The HIV epidemic of the 1980s and 1990s was paralleled by a resurgence of TB and outbreaks in occupational settings such as healthcare facilities and correctional institutions. Although TB cases have declined in the U.S. in recent years, the disease still endangers personnel in settings at high risk for exposure to persons with unsuspected or undiagnosed infectious TB. Disease transmission can occur in many types of healthcare facilities, including hospitals, nursing homes, and outpatient clinics. It can also occur in other high risk settings, such as correctional institutions.

“Tuberculosis is pernicious and insidious, an age-old illness that still poses risks to the dedicated healthcare 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 healthcare 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 may also 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. NIOSH-funded research by the University of Colorado helped to develop the guidelines. The guidelines discuss factors influencing the effectiveness of UVGI, such as UVGI irradiance and dose, mechanical ventilation, air mixing, humidity and temperature. The guidelines recommend consulting with a professional knowledgeable in upper-room UVGI systems and their installation before instituting the controls. The guidelines are practical with sections on

• How to select UV lamps
• How to install the system
• How to maintain the system

While enough information is available to guide the installation and maintenance of UVGI systems, the document notes that additional research is needed to enhance the guidelines. This includes research on variables such as air mixing and measurement of UV irradiance levels in the upper room. More information on occupational prevention and control of TB can be found at http://www.cdc.gov/niosh/topics/tb/.