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Introduction to Infection Prevention

Course Number: 582

Transmission-based Precautions

When Standard Precautions do not completely interrupt the transmission of a pathogen, Transmission-based Precautions are implemented.1 These precautions may be applied empirically, predicated on clinical signs and symptoms of infection, until the suspected pathogen is either identified or the infectious status of the patient is ruled out. Transmission-based Precautions include: (1) contact precautions, (2) droplet precautions, and (3) airborne precautions associated with droplet nuclei.1

Transmission-based Precautions should remain in effect for limited periods of time, i.e., while the risk for transmission of the infectious agent persists or for the duration of the illness.1 For most infectious diseases, this time period reflects known patterns of persistence or shedding of pathogens related to the natural history of the infectious process and its treatment.1 For some diseases, Transmission-based Precautions remain in effect until culture or antigen-detection tests become negative.1

Individuals with congenital, acquired, or therapeutic immunosuppression and those with chronic debilitating diseases may shed pathogenic organisms for prolonged periods of time and transmission may occur during apparent asymptomatic periods; therefore, the duration of contact, droplet, or airborne precautions may extend for many weeks or even months.1 Finally, it may be prudent to assume that persons with multidrug-resistant organisms remain permanently colonized.1