what are the two tiers of precautions to prevent the transmission of infectious agents?

The two tiers of precautions to prevent the transmission of infectious agents are Standard Precautions and Transmission-Based Precautions.

Standard Precautions

Standard Precautions are the basic level of infection prevention used for the care of all patients in all healthcare settings, regardless of whether infection is suspected or confirmed. They include measures such as hand hygiene, appropriate use of personal protective equipment (PPE) like gloves and masks, safe injection practices, and proper cleaning and disinfection of equipment and the environment.

Transmission-Based Precautions

Transmission-Based Precautions are additional measures used for patients known or suspected to be infected or colonized with specific pathogens that require extra steps to prevent spread. These precautions are organized into three main categories—Contact, Droplet, and Airborne Precautions—and are always used in combination with Standard Precautions when standard measures alone are not enough to interrupt transmission.

TL;DR:

• Tier 1: Standard Precautions – for every patient, every time.

• Tier 2: Transmission-Based Precautions – extra measures (contact, droplet, airborne) for certain infections, always added on top of Standard Precautions.

Information gathered from public forums or data available on the internet and portrayed here.