Hazard categories of microorganisms
Start with the big picture
Hazard Groups range from HG1, associated with negligible risk, to HG4, associated with high-mortality infections that are easily transmissible and lack reliable therapy. Examples in the source include Lactobacillus spp. and Bacillus subtilis in HG1; Staphylococcus aureus, Salmonella, HBV, and HSV in HG2; Mycobacterium tuberculosis, SARS-CoV-2, and Yersinia pestis in HG3; and Ebola, Marburg, and Lassa in HG4. Containment controls increase with risk and are selected alongside a risk assessment covering the agent, procedure, scale, worker susceptibility, and post-exposure planning. The topic also introduces biosecurity for select agents, vaccination or prophylaxis where available, validated decontamination, and accessible safety documentation.
What you'll learn
- Explain the factors used to classify microorganisms into Hazard Groups 1–4.
- Distinguish the broad risk characteristics and examples associated with each Hazard Group.
- Describe how hazard classification informs containment and laboratory controls.
- Identify key elements of risk assessment, exposure planning, and biosecurity.
- Summarize the roles of prophylaxis, decontamination, and point-of-use documentation.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
