Department of Health

Principles of infection prevention and control

An overview of infection prevention and control (IPC) strategies to reduce COVID-19, based on the chain of infection and hierarchy of controls.

2.1. The chain of infection

Transmission of infectious agents requires the following elements:

  • a causative agent/pathogen (for example SARS-CoV-2)
  • a reservoir
  • a portal of exit
  • a means of transmission
  • a portal of entry
  • a susceptible host.
The 6 elements of the chain of infection: causative agent, resevoir, portal of exit, means of transmission, portal of entry, susceptible host

Infection prevention and control measures aim to break one or more of the links in the chain to limit or prevent the transmission of the pathogen.

2.2. Hierarchy of controls

This is a model for managing occupational hazards in the workplace. The hierarchy ranks risk avoidance and risk mitigation strategies in decreasing order of reliability. Multiple control strategies are required to eliminate or minimise the risk of infection.

Hierarchy of controls

A hierarchy that ranks risk avoidance and risk mitigation strategies in decreasing order of reliability
Model Code of Practice: How to manage work health and safety risks - Safe work Australia <>
Hierarchy of controls

A diagram ranking health and safety control measures from the highest, most reliable level of protection to the lowest, least reliable level.

From highest to lowest protection, the measures are:

  1. Eliminate risks.
  2. Substitute the hazard with a safer alternative; isolate the hazard from people; reduce the risks through engineering control.
  3. Reduce exposure to the hazard using administrative controls.
  4. Use personal protective equipment.
Download Hierarchy of controls

2.3. Strategies to reduce COVID-19 transmission

COVID-19 infection prevention and control strategies should be aligned to the hierarchy of controls approach to risk.

Table 1. Hierarchy of controls and infection control strategies

Hierarchy of controls Example IPC strategies


Removal of the virus from the workplace and therefore eliminate the risk of transmission.

Elimination of the COVID-19 virus itself is unlikely.

Exclude unwell staff from the workplace

Offer alternative work options for at-risk staff

Screen staff and visitors prior to entry to the workplace

Use telehealth to minimise face-to-face consultations


Finding other ways to provide care that reduce potential for transmission.

Use telehealth in place of face-to-face consultations.

Consider conducting activities outdoors.


Isolation of infected persons to prevent potential transmission.

Use Class N negative pressure rooms for COVID-19 positive patients. If not available, use standard isolation rooms or single rooms with private bathrooms.

Cohort groups.

Use of patient zones.


Changes to infrastructure or equipment or change systems of work.

Optimise ventilation systems/zones in buildings.

Use air cleaning devices.

Consider the use of clear perspex screens (with caution).



Implementation of policies and protocols to guide practices that reduce risk.

Implement policies such as:

  • vaccination programs
  • respiratory protection programs
  • standard and transmission-based precautions procedures
  • surveillance
  • physical distancing
  • education and training.

Personal protective equipment

Worn to protect the wearer from infection.

Use transmission-based precautions.

Use PPE (masks, respirators, gowns, gloves, and eye protection).

Reviewed 22 November 2023

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