Infection Prevention and Control

Transmissions Based Precautions

Transmission-based Precautions are used in addition to Standard Precautions for patients with known or suspected infections. The type of Transmission-based Precautions assigned to a patient depends on the transmission route of the microorganism: contact, droplet, or airborne.

Learning Objectives

In this module, you will learn how to:

  • Explain the rationale for Transmission-based Precautions.
  • Differentiate between Contact, Droplet and Airborne Precautions.
  • Identify elements of Transmission-based Precautions, such as patient placement, environmental cleaning, and patient transport.

Learning Activities Module time:

  • Transmission-based Precautions (5 min)

    As you have learned in other modules, Standard Precautions are required for care of all patients in any healthcare setting. These include:

    • hand hygiene
    • personal protective equipment (PPE)
    • respiratory hygiene
    • safe injection practices
    • cleaning of the environment and patient-care equipment
    • laundry handling
    • waste management

    Review the Standard Precautions modules if you need more information.

    Transmission-based Precautions, sometimes called isolation precautions, are used in addition to Standard Precautions for patients known or suspected to have microorganisms for which extra precautions are needed to prevent transmission. Patients are placed on Transmission-based Precautions when they are infected or colonized with known or suspected pathogens.

    Colonization occurs when microorganisms are present on a host individual but the individual does not show clinical symptoms or findings of an active disease. A colonized individual can transmit infectious microorganisms to other individuals.

    Transmission-based Precautions are used based on clinical observation when certain pathogens are suspected, and then continued if an infectious cause is confirmed or stopped if an infectious cause is ruled out. Laboratory tests, especially those that rely on cultures, can take two or more days for results. Therefore, Transmission-based Precautions must be implemented as soon as these pathogens are suspected and continued while the test results are pending. Use of appropriate Transmission-based Precautions at the time a patient develops symptoms or arrives at the healthcare facility reduces opportunities for transmission.

    The type of Transmission-based Precaution assigned to a patient depends on the mode of transmission of the suspected or known pathogen. There are three main modes: contact, droplet and airborne.

    • Contact transmission: This is the most common mode of transmission. Contact transmission occurs when microorganisms are transmitted from one infected or colonized person to another via direct or indirect contact. For example, when healthcare personnel touch a patient’s skin, their hands can become contaminated with microorganisms from that patient. If the HCP then touches another patient without performing hand hygiene, they have carried microorganisms to the second patient.

      Examples of pathogens that can spread via contact transmission include many gastrointestinal pathogens that cause diarrhea, and bacteria such as Klebsiella pneumoniae, E. coli, and Staphylococcus aureus.

    • Droplet transmission: This type of transmission occurs via sprays or splashes of respiratory secretions. Droplets are small amounts of liquid from the lungs, mouth, or nose that are expelled into the air when people cough, sneeze, or even just talk. These droplets can get onto a susceptible person’s eyes, nose, or mouth and can sometimes cause infection. Droplets can contaminate environmental surfaces and lead to further contact transmission.

      Examples of pathogens that spread via droplet transmission include seasonal influenza virus and Bordetella pertussis (pertussis).

    • Airborne transmission: This type of transmission occurs when microorganisms are aerosolized into tiny particles that become suspended in air and travel on air currents over long distances. This can happen when an infected person coughs, talks, or sneezes. Microorganisms can also be aerosolized during medical procedures and by medical equipment. Since some microorganisms can survive on air currents over long periods, they can be inhaled by susceptible persons who have not had face-to-face contact (or been in the same room) with an infectious person.

      Examples of pathogens that spread via airborne transmission are Mycobacterium tuberculosis (TB) and the measles virus.

    You’ll learn more about implementing precautions for each type of transmission in the sections below.

  • Patient Placement, Patient Transport, and Environmental Cleaning (10 min)

    Implementing Transmission-based Precautions will look different from facility to facility, depending on local or national guidelines, facility policies, building design, space constraints, and available equipment and supplies. Remember that the principles described below are recommendations intended to limit transmission of pathogens during health care and keep both patients and HCP safe.

    Click or tap each tab to learn more about each of these elements. As you read through this section, think about how you would implement Transmission-based Precautions based on the resources at your facility.

    Also remember that patients who are being isolated as a result of Transmission-based Precautions need additional psychosocial support during care.

    Initial patient evaluation

    As an IPC professional, you might be asked for advice for triage protocols when patients arrive at the registration desk or emergency department.

    When patients arrive for registration, HCP should evaluate their signs and symptoms and check the medical records to decide whether any Transmission-based Precautions are indicated.

    Here are examples of symptoms and the Transmission-based precautions that would be warranted:

    • Patients with respiratory symptoms: mask and a private room to prevent spreading influenza.
    • Patients with a history of TB: negative pressure room for respiratory isolation until the patient is evaluated.
    • If hemorrhagic fevers are possible in the setting, a patient with possible symptoms and exposures: isolation in private room until further evaluation.
    Patient placement

    Wherever possible, dedicate a private room for a patient on Transmission-based Precautions. If there are not enough private rooms, prioritize the rooms for patients likely to be most infectious. These patients might be ones who are coughing, have active diarrhea, or have high fevers. Place additional patients needing isolation in a low-traffic area and maximize the distance from other patients. Use barriers, such as curtains, chairs, rope, or other material, to mark off the isolation area.

    As an IPC professional, you will consult with supervisors on a ward to determine solutions for where to place patients on Transmission-based Precautions. These solutions will look different from ward to ward and facility to facility because of building design, ward layout, number of patients, and available resources. Remember that effective patient placement reduces the risk of transmitting a pathogen to other patients.

    Cohorting patients

    If many patients are infected or colonized with the same pathogen, consider cohorting patients. Cohorting is the practice of placing similar patients in one area to confine their care and prevent contact with other patients. Patient cohorts are most often used when clusters of infection occur, or during outbreaks.

    Clearly mark off the area as being for isolated patients only and control access to the area if possible.

    Cohorting staff

    Cohorting staff is dedicating HCP so that only a limited number of staff are interacting with patients in isolation. Those staff do not provide care to non-isolation patients. This is an additional layer of administrative control that might be beneficial in settings experiencing clusters or outbreaks to prevent inadvertent transmission via HCP. Note that this can be difficult to implement when there are staff shortages. You’ll learn more about strategies to control outbreaks in the Outbreak Investigation module.

    Patient-care items and environmental cleaning

    Whenever possible, use disposable or dedicated patient-care equipment for patients on Transmission-based Precautions. If non-critical patient care items (e.g., blood pressure cuffs) must be shared, make sure that these items are cleaned and disinfected prior to use on the next patient.

    At a minimum, all patient-care areas should be routinely cleaned once a day, and more often when contamination is visible. For patients on Transmission-based Precautions, more frequent cleaning may be required, especially in multi-bed rooms. Rooms should receive terminal cleaning whenever a patient is discharged or transferred, or when precautions have been discontinued.

    To refresh your memory of these protocols, please reference the Environmental Cleaning module under the Standard Precautions topic in this course and consult the resources in that module.

    Patient transport outside of a room

    Limit patient movement out of private or shared rooms to medically necessary purposes, such as diagnostic tests or therapeutic procedures that cannot be performed in the room.

    If a patient on Transmission-based Precautions needs to leave their room for a test or procedure:

    • Patients on Droplet or Airborne precautions should wear a surgical mask when outside of the patient room.
      • HCP do not need to wear masks when transporting patients with respiratory infections if the patient is wearing a mask. The patient's mask provides appropriate protection for HCP and other individuals encountered during transportation.
      • If the patient cannot tolerate a mask, HCP should put on a mask for patient transport and provide tissues to the patient to use when coughing.
    • Cover any exposed wounds with appropriate dressings.
    • Clean and disinfect any wheelchair or trolley used.

    As a reminder, PPE should not be worn outside of the patient room, except as needed for patient transport.

    Signage

    Use standardized, easily visible signs to alert clinical and support staff when patients are placed on Transmission-based Precautions. Any signage should consider patient privacy, dignity, and confidentiality. All HCP should be routinely trained to read and understand these signs.

    Signage should include:

    • a reminder to pause and read the sign before entering the patient room
    • the type of Transmission-based Precautions in use
    • a reminder to perform hand hygiene
    • instructions for appropriate PPE to be put on before HCPs or visitors enter the patient room
  • Knowledge Check (5 min)

    1Match the transmission route with its definition:

    2A patient presents at the emergency department with respiratory symptoms. It is flu (influenza) season in your community. The nurse calls you, the IPC professional, to consult. What initial actions should you recommend to the nurse? (Select all that apply.)

    3Cohorting is the practice of placing patients colonized or infected with the same pathogen in one area to confine their care to one area and prevent contact with other patients.

    4Patients A and B are both on contact precautions. Can you use the same stethoscope on both patients?

  • Contact Precautions (5 min)

    Patients are placed on Contact Precautions when they have suspected or known infections that are spread by touch or contact with the patient or the patient’s environment, surfaces, and equipment. Organisms or conditions that require Contact Precautions include multidrug-resistant (MDR) organisms such as MDR Acinetobacter baumannii, abscesses with major draining, and incontinence or severe diarrhea.

    Click or tap on each tab to learn more about implementing Contact Precautions:

    Patient placement

    Isolate patients who require Contact Precautions in a private room. When single-patient rooms are in short supply or not available:

    • Prioritize any single-patient rooms for patients with conditions that may spread pathogens (e.g., fecal incontinence).
    • If it becomes necessary to place a patient on Contact Precautions in a room with patients who are not infected or colonized with the same pathogen, avoid placing that patient in an area with immunocompromised patients, for example, pregnant patients or burn patients.
    • Make sure that patients are physically separated (more than 1 meter/3 feet apart) from each other; if there are privacy curtains, make sure they are closed. Consider using physical barriers to prevent HCP from moving directly from a patient on Contact Precautions to one that is not.
    • If in a shared room with a toilet, patients should avoid sharing a toilet; one patient can be offered a bedside commode or bedpan.
    PPE
    • Put on a clean, non-sterile gown and gloves before entering the patient-care area.
    • Remove and properly discard PPE before exiting the patient room. Perform hand hygiene immediately after removing PPE.
    • For multibed patient rooms or wards, do not use the same PPE with more than one patient. Remove PPE, perform hand hygiene and put on new PPE before coming into contact with another patient.
    Patient equipment and environmental cleaning
    • Use disposable or dedicated patient-care equipment (for example, stethoscopes) and clean and disinfect equipment before use on other patients.
    • Make sure that rooms of patients on Contact Precautions are cleaned with increased frequency (for example, more than once a day), with a focus on frequently touched surfaces and equipment, such as bed rails, doorknobs, and toilets.
    • Use gloves and gown when cleaning patient care equipment and the environment of a patient who has been on Contact Precautions. Remove and discard gloves and gowns immediately after cleaning is complete.
    Patient transport outside of a room
    • When transport is necessary, ensure any wounds or lesions on the patient’s body are covered.
    • Remove and dispose of PPE, then perform hand hygiene, prior to transporting patients on Contact Precautions. DO NOT wear PPE outside of a patient’s room.
    • Put on clean PPE to assist the patient once you have reached the destination in the hospital.
  • Droplet Precautions (5 min)

    Patients are placed on Droplet precautions when they have known or suspected infections transmitted by respiratory droplets. Droplets are small amounts of liquid from the lungs, mouth or nose that are expelled into the air when people cough, talk or sneeze. Droplets can also spread via hands when people sneeze or cough into their hands and then touch mucous membranes of another person.

    Because these pathogens do not remain infectious over long distances in a health care facility, special air handling and ventilation are not needed to prevent droplet transmission.

    Organisms or infections that require Droplet precautions include Bordetella pertussis (whooping cough), seasonal influenza virus, Neisseria meningitidis (bacterial meningitis), and certain types of pneumonia.

    Click on each tab to learn more about implementing Droplet precautions:

    Patient placement

    Single-patient rooms are preferred for patients who require Droplet precautions. When single-patient rooms are in short supply or not available, apply the following principles to help decision-making:

    • Prioritize any single-patient rooms for patients with excessive cough and sputum production.
    • If it becomes necessary to place a patient on Droplet precautions in a room with patients who are not infected with the same pathogen, avoid placing that patient in an area with immunocompromized patients.
    • Ensure patients are physically separated (more than 1 meter/3 feet apart) from each other; if there are privacy curtains, make sure they are drawn.
    PPE
    • Put on a mask (NOT a respirator) before entering the patient-care area. Additional PPE might be indicated, depending on the nature of the patient interaction—in other words, based on a risk assessment. Consult any local or national guidelines for additional guidance.
    • Remove and properly discard PPE before exiting the patient room. Perform hand hygiene immediately after removing PPE.
    Patient transport outside of a room
    • When transport is necessary, instruct the patient to wear a mask and follow Respiratory Hygiene and Cough Etiquette.
    • No mask is indicated for HCWs transporting patients on Droplet precautions.
      • If the patient cannot tolerate a mask, HCP should put on a mask for patient transport and provide tissues to the patient to use when coughing.

    Emerging organisms that spread via droplets, such as the viruses that cause severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), have additional precautions recommended to limit transmission. Consult disease-specific guidance (links in References) for preventing transmission of these organisms.

  • Airborne Precautions (5 min)

    Patients are placed on Airborne precautions when they have known or suspected infections transmitted over long distances through the air.

    Organisms that require Airborne Precautions include Mycobacterium tuberculosis, the measles virus, and the varicella zoster virus (chickenpox).

    Click the tab(s) below to read more about implementing Airborne precautions:

    Airborne infection isolation room

    Ideally, patients should be placed in an airborne infection isolation room (AIIR). Remember, this is a room specifically designed with special air handling and ventilation systems to prevent transmission of airborne infections. AIIR design includes:

    • negative pressure (air flows from corridor to inside the patient room) compared to the corridor, and 6—12 air exchanges per hour
    • direct exhaust of air to the outside, away from places where people walk or congregate and any air intake openings
    • a door kept closed when not required for entry and exit
    No airborne infection isolation room

    If an AIIR is not available, place patients in a room designed with ventilation in mind and keep doors closed.

    Ideally, any room intended for patients on Airborne Precautions is away from heavy traffic areas in the healthcare facility and does not share ventilation with any other patient rooms or wards.

    Ventilation moves outdoor air into a building or a room and distributes the air within that building or room. Natural ventilation is when natural forces, such as wind, move air in and out of a room. [Consult WHO Manual on Natural Ventilation for Infection Control in Healthcare Settings]

    To provide natural ventilation:

    • Use a room that has good cross-ventilation (two or more windows that open) to the outdoors.
    • Use an exhaust fan in one window to assist moving room air to the outdoors, making sure the exhaust window is away from people and any air intake openings.
    • Turn off air-conditioning and open windows to enhance ventilation if an independent air supply is not available.
    • Keep the door to the hallway closed, except for when HCP enter and exit the room.

    Find design and operational requirements for natural ventilation in healthcare facilities in the Resources section.

    PPE
    • Put on a particulate respirator, such as a fit-tested N95 mask, and conduct a seal check before entering the patient’s room. A seal check should be performed every time the N95 mask is worn.
    • Gown, gloves, and eye protection are not needed for many organisms transmitted exclusively by the airborne route (such as M. tuberculosis, and the varicella virus), but may be needed when an infectious microorganism is transmitted by multiple routes or when multiple pathogens are possible, as is the case with influenza and tuberculosis.
    Patient transport outside of a room
    • When transport is necessary, instruct the patient to wear a mask and follow respiratory hygiene and cough etiquette.
    • Cover any skin lesions associated with varicella or M. tuberculosis to prevent aerosolization or contact with the pathogen in skin lesions.
    • No mask or respirator is indicated for HCP transporting patients on Airborne Precautions if the patient is wearing a mask and infectious skin lesions are covered.
      • If the patient cannot tolerate a mask, HCP should put on a mask for patient transport and provide tissues to the patient to use when coughing.
  • Knowledge Check (10 min)

    Scenario 1

    1There is one isolation room in the male medical ward. On the ward is a patient with multidrug-resistant (MDR) Acinetobacter baumanii. Another patient has just been admitted with a history of TB infection. Which patient should be prioritized to move to the isolation room?

    2What PPE should Aziza, the nurse, put on before caring for a patient on Contact precautions?

    3Aziza’s patient with MDR Acinetobacter baumanii has been discharged. There is another patient being admitted to the ward who needs the bed. What precautions should be taken for cleaning a bed space of a patient on Contact Precautions? (Select all that apply.)

    Scenario 2

    Lucia is preparing an isolation area for a patient with seasonal influenza. Her facility does not have private or single rooms, so she must find space for this patient. Finding isolation areas has not been an easy task. She has asked you, an IPC focal person, for help.

    1What Transmission-based precaution is appropriate for this patient?

    2What is the best isolation solution for this patient?

    3Lucia’s facility does not have a portable X-ray and Lucia needs to transport the patient to another part of the facility for an X-ray. What precaution should be taken to transport the patient?

    4The patient’s family has arrived for visiting hours. Does the patient’s family need to wear PPE?

    Scenario 3

    Somchai is taking care of a pneumonia patient. On the second day of hospitalization, he learns from the patient’s family that the patient has been losing weight over the last several months and having drenching night sweats. Somchai suspects that the patient has tuberculosis and calls you for recommendations.

    1What Transmission-based precaution is appropriate for this patient?

    2The facility does not have an AIIR. You assist in setting up a private area designed for natural ventilation. Which of the following is not a consideration for natural ventilation?

  • Summary (5 min)

    Unlike Standard Precautions, which are used for all patient care, Transmission-based precautions are used only for those patients who might be infected or colonized with certain microorganisms for which the mode of transmission is known. Conduct an initial patient evaluation upon the patient’s arrival to determine the potential pathogen and the precautions to take when caring for that patient. Patient placement and environmental cleaning protocols for Transmission-based Precautions should be in place at your facility. This module has also provided information on adaptations for facilities that cannot provide private rooms or isolation areas.

    Precautions for contact, droplet and airborne transmission consider where patients are placed, PPE worn, equipment used for the patient, and frequency of cleaning. Managing these factors appropriately in addition to using Standard Precautions will reduce the spread of potential pathogens in your facility.

    A more thorough list of recommended precautions for selected infections and conditions is in the Resources section.

  • References
    1. Centers for Disease Control and Prevention (CDC), Siegel JD, Rhinehart E, Jackson M, Chiarello L, the Healthcare Infection Control Practices Advisory Committee (HICPAC). 2007 Guideline for isolation precautions: preventing transmission of infectious agents in healthcare settings. Atlanta, GA: CDC/HICPAC; 2007. http://www.cdc.gov/hicpac/pdf/isolation/Isolation2007.pdf.
    2. Centers for Disease Control and Prevention (CDC), CDC Information on Avian Influenza. Guideline for isolation precautions: preventing transmission of infectious agents in healthcare settings (2007). https://www.cdc.gov/flu/avianflu/ Last update: October 2017. Page 88 of 203; accessed May 2016.
    3. Tietjen L, Bossemeyer D, McIntosh N. Infection prevention: guidelines for healthcare facilities with limited resources. Baltimore, MD: Jhpiego; 2003.
    4. World Health Organization (WHO). Infection control strategies for specific procedures in health-care facilities: epidemic-prone and pandemic-prone acute respiratory diseases: a quick reference guide. 2008.
    5. Atkinson J, Chartier Y, Pessoa-Silva CL, Jensen P, Li Y, Seto W-H, editors. Natural ventilation for infection control in health-care settings. Geneva: World Health Organization (WHO); 2009.