Biosafety Categorisations and Containment Levels

The Control of Substances Hazardous to Health Regulations 2002 (COSHH) classifies biological agents into four categories (Hazard Groups) according to an approved list by the Health and Safety Executive (HSE). Biological agents are bacteria, viruses, parasites, and fungi that can cause harm to human health, usually due to infection, although some are toxic or can cause an allergy. The approved list is relevant to risk assessment for work with biological agents and the application of appropriate control measures. Hazard Group 1 agents are not considered to pose a risk to human health, while Hazard Group 4 agents present the greatest risk. The principle of the categorization is laid down by the Advisory Committee on Dangerous Pathogens (ACDP) based on the following (see also Table 13.1): ● the likelihood that it will cause disease by infection or toxicity in humans; ● how likely it is that the infection would spread to the community; and ● the availability of any prophylaxis or treatment. The ACDP only considers the risks to human health when deciding appropriate classification. Some listed agents can also cause disease in animals (zoonoses) and have also been assigned a hazard classification under the Specified Animal Pathogens Order (SAPO). In allocating human pathogens to a hazard group, no account is taken of particular effects on those whose susceptibility to infection may be affected, for example, because of pre-existing disease, medication, compromised immunity, pregnancy, or breastfeeding. Type 2 polio virus has been reclassified from Hazard Group 2 to Hazard Group 3 to bring the UK in line with the expectations of World Health Organization’s global polio eradication programme. This reclassification also applies to attenuated type 2 polio viruses once this component is no longer used as part of the trivalent polio vaccine. Zika virus has been reclassified from Hazard Group 3 to Hazard Group 2 as there is substantial evidence that while it can cause human disease, this is generally mild. It is also unlikely to spread to the community from the laboratory. COSHH regulations specify four containment levels for activities which involve working with biological agents.