Medical isolation is a necessary public health practice in healthcare facilities, designed to contain and prevent the spread of infectious diseases. It involves a systematic set of practices to interrupt the transmission of pathogens from an infected patient to others. While many general safety protocols are always in place, there are three primary categories of enhanced measures, known as Transmission-Based Precautions (TBP), used when a patient is known or suspected to have a contagious illness. These additional protocols dictate the specific personal protective equipment (PPE) and environmental controls required to safely deliver patient care and protect healthcare personnel.
Setting the Foundation: Standard Precautions
All patient care begins with a baseline of safety known as Standard Precautions, which are meant to be applied universally to every patient encounter, regardless of diagnosis or presumed infection status. These practices form the foundation of infection control, protecting healthcare workers and patients from recognized and unrecognized sources of infection alike. Key elements include meticulous hand hygiene, such as washing hands with soap and water or using alcohol-based hand rub. Standard Precautions also cover the appropriate use of PPE, safe injection practices, and respiratory hygiene. The three types of isolation discussed next are designated as Transmission-Based Precautions (TBP) and are always used in addition to these core practices.
Contact Precautions
Contact Precautions are the most frequently implemented type of TBP and are used for infections spread by direct contact with the patient or indirect contact with contaminated surfaces or equipment in the patient’s room. Pathogens that survive well on environmental surfaces often require this level of precaution. Examples include Clostridioides difficile (C. difficile), Methicillin-resistant Staphylococcus aureus (MRSA), and Vancomycin-resistant Enterococcus (VRE).
The required barrier methods for personnel entering the room include wearing a clean gown and gloves, which must be donned before entry and carefully removed at the room’s exit. Dedicated patient-care equipment is often used to prevent cross-contamination. Thorough hand hygiene, especially using soap and water for spore-forming organisms, is performed immediately after removing the PPE.
Droplet Precautions
Droplet Precautions are implemented for diseases transmitted through relatively large respiratory particles expelled when an infected person coughs, sneezes, or talks. These droplets fall out of the air quickly, typically traveling less than 3 to 6 feet from the source. Pathogens requiring this isolation include those causing Influenza, Pertussis (whooping cough), and Mumps.
The specific barrier for healthcare personnel is a surgical mask, which must be worn upon entering the patient’s room. Respirators are generally not required because the particles do not remain suspended in the air over long distances. If the patient must leave the room for essential procedures, they are instructed to wear a surgical mask to minimize the spread of their respiratory secretions.
Airborne Precautions
Airborne Precautions are reserved for the most highly contagious pathogens that can remain suspended in the air as fine, small particles, often referred to as aerosols. These particles can travel on air currents over long distances and remain viable for extended periods. This mode of transmission requires a specialized level of environmental control that goes beyond standard PPE.
Patients are required to be placed in an Airborne Infection Isolation Room (AIIR), commonly known as a Negative Pressure Room. This specialized room is engineered to maintain a lower air pressure inside compared to the outside hallway, causing air to flow inward when the door is opened. The air within the room is then exhausted directly to the outside or passed through a High-Efficiency Particulate Air (HEPA) filter before recirculation. Healthcare workers must wear a specially fitted N95 respirator or a powered air-purifying respirator (PAPR) before entering the AIIR. Infections requiring these stringent controls include Tuberculosis, Measles, and Varicella (chickenpox).