Infectious Diseases

Healthcare workers (HCWs) are occupationally exposed to a variety of infectious diseases during the performance of their duties. The delivery of healthcare services requires a broad range of workers, such as physicians, nurses, technicians, clinical laboratory workers, first responders, building maintenance, security and administrative personnel, social workers, food service, housekeeping, and mortuary personnel. Moreover, these workers can be found in a variety of workplace settings, including hospitals, nursing care facilities, outpatient clinics (e.g., medical and dental offices, and occupational health clinics), ambulatory care centers, and emergency response settings. The diversity among HCWs and their workplaces makes occupational exposure to infectious diseases especially challenging. For example, not all workers in the same healthcare facility, not all individuals with the same job title, and not all healthcare facilities will be at equal risk of occupational exposure to infectious agents.

The primary routes of infectious disease transmission in U.S. healthcare settings are contact, droplet, and airborne. Contact transmission can be sub-divided into direct and indirect contact. Direct contact transmission involves the transfer of infectious agents to a susceptible individual through physical contact with an infected individual (e.g., direct skin-to-skin contact). Indirect contact transmission occurs when infectious agents are transferred to a susceptible individual when the individual makes physical contact with contaminated items and surfaces (e.g., door knobs, patient-care instruments or equipment, bed rails, examination table). Two examples of contact transmissible infectious agents include Methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-resistant enterococcus (VRE).

Droplets containing infectious agents are generated when an infected person coughs, sneezes, or talks, or during certain medical procedures, such as suctioning or endotracheal intubation. Transmission occurs when droplets generated in this way come into direct contact with the mucosal surfaces of the eyes, nose, or mouth of a susceptible individual. Droplets are too large to be airborne for long periods of time, and droplet transmission does not occur through the air over long distances. Two examples of droplet transmissible infectious agents are the influenza virus which causes the seasonal flu and Bordetella pertussis which causes pertussis (i.e., whooping cough).

Airborne transmission occurs through very small particles or droplet nuclei that contain infectious agents and can remain suspended in air for extended periods of time. When they are inhaled by a susceptible individual, they enter the respiratory tract and can cause infection. Since air currents can disperse these particles or droplet nuclei over long distances, airborne transmission does not require face-to-face contact with an infected individual. Airborne transmission only occurs with infectious agents that are capable of surviving and retaining infectivity for relatively long periods of time in airborne particles or droplet nuclei. Only a limited number of diseases are transmissible via the airborne route. Two examples of agents that can be spread through the airborne route include Mycobacterium tuberculosis which causes tuberculosis (TB) and the measles virus (Measles morbillivirus), which causes measles (sometimes called "rubeola," among other names).

Several OSHA standards and directives are directly applicable to protecting workers against transmission of infectious agents. These include OSHA's Bloodborne Pathogens standard (29 CFR 1910.1030) which provides protection of workers from exposures to blood and body fluids that may contain bloodborne infectious agents; OSHA's Personal Protective Equipment standard (29 CFR 1910.132) and Respiratory Protection standard (29 CFR 1910.134) which provide protection for workers when exposed to contact, droplet and airborne transmissible infectious agents; and OSHA's TB compliance directive which protects workers against exposure to TB through enforcement of existing applicable OSHA standards and the General Duty Clause of the OSH Act.