Tuberculosis (TB) – An infectious bacterial disease transmitted through the air that mainly affects the lungs.
With rare exceptions, TB is infectious only when it occurs in the lungs or larynx. TB that occurs elsewhere in the body is usually not infectious, unless the person also has TB in the lungs or larynx at the same time.
According to the Centers for Disease Control and Prevention (CDC), an estimated 2 billion persons (i.e., one third of the world’s population) are infected with M. tuberculosis. Tuberculosis kills almost 1.6 million people per year. Although the 2007 TB rate (4.4 cases per 100,000 population) was the lowest recorded in the United States since national reporting began in 1953, the average annual decline has slowed since 2000. TB is now the second most common cause of death from infectious disease in the world after human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS).
Characteristics of persons exposed to M. tuberculosis that might affect the risk for infection are not well defined. The probability that a person who is exposed to M. tuberculosis will become infected depends primarily on the concentration of infectious droplet nuclei in the air and the duration of exposure to a person with infectious TB disease. The closer the proximity and the longer the duration of exposure, the higher the risk is for being infected. Additional hazards are now present because of multidrug-resistant (MDR) TB. MDR organisms are resistant to the drugs that are normally used to treat TB, such as Isoniazid and Rifampin. The course of treatment when treating MDR TB increases from 6 months to 18-24 months, and the cure rate decreases from nearly 100% to less than 60%. Mortality among patients with MDR-TB can be high.
TB disease in persons over the age of 65 constitutes a large proportion of TB cases in the United States. Many of these individuals have latent TB infection; however, with aging these individuals’ immune function starts to decline, placing them at increased risk of developing active TB disease, and employees in long-term care facilities at risk of occupational exposure to TB. Nursing homes or long-term care facilities for the elderly have been identified as having a high-risk situation for the transmission of TB. The degree of risk of occupational exposure of a worker to TB will vary based on a number of factors.
OSHA withdrew its 1997 proposed standard on Occupational Exposure to Tuberculosis because it is unlikely to result in a meaningful reduction of disease transmission caused by contact with the most significant remaining source of occupational risk: exposure to individuals with undiagnosed and unsuspected TB.
Although OSHA has no standard for TB Infection Control, it will enforce the “General Duty Clause” in situations where employers’ failure to implement available precautions exposes workers to the hazard of TB infection. Created under the Occupational Safety & Health Act of 1970, the General Duty Clause can be thought as an employer’s general responsibility to ensure the safety of all its employees and states: “Each employer shall furnish to each employee a place of employment which is free from recognized hazards that cause or are likely to cause death or serious physical harm & each employee shall comply with the occupational safety & health standards and all rules, regulations and orders issued pursuant to this Act which are applicable to his own actions and conduct.” Additionally, OSHA requires employers with employee exposure to TB must comply with certain requirements including: 1910.134 – Respiratory Protection, 1910.145 – Accident Prevention Signs and Tags, and 1904 – Recordkeeping.
Under the General Duty Clause, OSHA will issue citations to employers with employees working in one of the workplaces where the CDC has identified workers as having a higher incidence of TB infection than the general population, when the employees are not provided appropriate protection and who have exposure as defined below:
Exposure to the exhaled air of an individual with suspected or confirmed pulmonary TB disease
Employee exposure without appropriate protection to a high hazard procedure performed on an individual with suspected or confirmed infectious TB disease and which has the potential to generate infectious airborne droplet nuclei.
Furthermore: OSHA will issue citations under the “General Duty Clause” in cases where the following procedures are not followed:
Periodic Evaluations: TB skin testing shall be conducted every three (3) months for workers in high risk categories, every six (6) months for workers in intermediate risk categories, and annually for low risk personnel. The CDC has defined the criteria for high, intermediate, and low risk categories.
When working with TB potential hazards, OSHA recommends the prompt implementation of early screening procedures, and staff training to help them identify potentially infectious individuals, which will allow for early identification of patients with infectious TB and the initiations of appropriate controls before occupational exposure occurs to staff and other patients.
OSHA encourages employers to follow the guidelines established by the Centers for Disease Control and Prevention (CDC), Division of Tuberculosis Elimination (DTBE) to minimize the potential of TB transmission.
Should TB exposure occur, OSHA Directive CPL 2.106 states individuals with suspected or confirmed infectious TB disease must be placed in a respiratory acid-fast bacilli (AFB) isolation room. High hazard procedures on individuals with suspected or confirmed infectious TB disease must be performed in AFB treatment rooms, AFB isolation rooms, booths, and/or hoods. (AFB isolation refers to a negative pressure room or an area that exhausts room air directly outside or through HEPA filters if recirculation is unavoidable).
OSHA requires all healthcare settings establish a TB infection control program designed to ensure prompt detection, airborne precautions, and treatment of persons who have suspected or confirmed TB disease.
Fundamentals of Effective TB Infection Control: