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.
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
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 |
|---|---|
Elimination 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 |
Substitution 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 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. |
Engineering 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). Vaccines. |
Administration Implementation of policies and protocols to guide practices that reduce risk. | Implement policies such as:
|
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