Risk Groups: What They Are and Why They Matter

Biological agents are classified into 1 of 4 risk groups based on factors such as:

•        virulence
•        infectivity
•        communicability
•        availability of effective prophylactic or therapeutic interventions

Biological agents can be:

•        proteins
•        microorganisms
•        nucleic acids, or biological material containing parts of them

Biological agents classified as Risk Group 1 are considered to present the lowest risk whereas those classified as Risk Group 4 are considered to present the highest risk to individuals and communities.

The risk group classification of a biological material generally dictates the laboratory containment level required for handling it (for example Risk Group 2 pathogens are handled at Containment Level 2), with some exceptions.

       For more information about exceptions, please consult: Biosafety directives and advisories.

Unless excluded or exempt, facilities that conduct controlled activities with Risk Groups 2, 3 and 4 human or animal pathogens or toxins require 1 or both of:

•         a Pathogen and Toxin Licence administrated by the Public Health Agency of Canada and issued under the Human Pathogens and Toxins Act and Human Pathogens and Toxins Regulations or the Health of Animal Act and Health of Animal Act, or
•         an import permit from the Canadian Food Inspection Agency and issued under the Health of Animal Act and the Health of Animal Act

Well-characterized biological materials with a pathogen risk assessment completed by the Public Health Agency of Canada or the Canadian Food Inspection Agency have been assigned a risk group and containment level. The risk group classification of thousands of biological agents is available in the online ePATHogen database. It provides a comprehensive and up-to-date list of biological agents and their risk group classifications, containment level requirements and other regulatory information.

        ePATHogen database

Most of the risk group classifications listed in the ePATHogen database are shown at the species level, or they may refer to a particular:

•         strain
•         isolate
•         variant
•         subspecies

Risk group classifications are also shown at the genus-level. However, unless a lack of information requires your pathogen to be classified at the genus level, best practices for determining the risk group of a pathogen are to classify it at the strain or isolate level. For example Escherichia spp. are classified as Risk Group 2 for humans and animals at the genus-level (see table). However, certain species within the genus are classified as Risk Group 1 for humans and animals (for example, E. blattae). Others are classified as Risk Group 2 for humans and animals (for example, E. coli). Similarly, E. coli is classified as Risk Group 2 for humans and animals at the species-level. However, certain strains or isolates are classified as Risk Group 1 for humans and animals (for example, strain K12).

To find out the risk group classification for a biological agent not listed in the ePATHogen database, complete a pathogen risk assessment using the template below.

•         Pathogen risk assessment template
•         Canadian Biosafety Guideline: Pathogen risk assessment

Submit the completed risk assessment to the Public Health Agency of Canada at pathogens.pathogenes@phac-aspc.gc.ca for validation.

Regulation of Cells and Cell Lines Under the Human Pathogens and Toxins Act and Regulations

Some cells or cell lines may also be regulated under the Human Pathogens and Toxins Act and Human Pathogens and Toxins Regulations. Cell lines with a Public Health Agency of Canada-completed risk assessment are listed in the ePATHogen database. A Statement of Administrative Intent clarifies the circumstances under which cells or cell lines are controlled under the Human Pathogens and Toxins Act. Generally, they don't meet the definition of a pathogen. However, if they contain or produce an intact Risk Groups 2, 3, or 4 human pathogen or toxin, they're controlled under the Human Pathogens and Toxins Act.

        Statement of Administrative Intent: Determining if cells and cell lines are under the authority of the Human Pathogens and Toxins Act

If it's unclear to a facility whether the cell or cell line contains an intact Risk Groups 2, 3, or 4 human pathogen or toxin, then a risk assessment should be conducted. It should consider whether the cell or cell line:

•         contains elements (for example, nucleic acids or proteins) derived from a pathogen, and
•         whether these elements are capable of producing an infectious or replication-competent pathogen

Always consult the Public Health Agency of Canada about the risk group classification and containment level requirements for cells and cell lines.

Don't Use Risk Group or Biosafety Level Classification Published by Other Organizations

Risk group or biosafety level classifications published by other organizations (for example, culture collections, distributors, manufacturers, and other countries) have no regulatory significance under the Human Pathogens and Toxins Act and Human Pathogens and Toxins Regulations. They may, but don't always, align with Canadian risk group classifications and containment level requirements. Always consult the ePATHogen database to determine the risk group and containment level of your biological agent or cell line.

        ePATHogen database

If in Doubt, Ask Us

If you have any questions about risk assessments or risk group classifications, including biological agents or cell lines not listed in the ePATHogen database, contact us at pathogens.pathogenes@phac-aspc.gc.ca.