Recommended Biosafety Levels for Infectious Agents and Infected Animals

Selection of an appropriate biosafety level for work with a particular agent or animal study depends upon a number of factors (see Section V, Risk Assessment). Some of the most important are: the virulence, pathogenicity, biological stability, route of spread, and communicability of the agent; the nature or function of the laboratory; the procedures and manipulations involving the agent; the endemicity of the agent; and the availability of effective vaccines or therapeutic measures.
Agent summary statements in this section provide guidance for the selection of appropriate biosafety levels. Specific information on laboratory hazards associated with a particular agent, and recommendations regarding practical safeguards that can significantly reduce the risk of laboratory-associated diseases, are included. Agent summary statements are presented for agents which meet one or more of the following criteria: the agent is a proven hazard to laboratory personnel working with infectious materials (e.g., hepatitis B virus, M. tuberculosis); the potential for laboratory-associated infections is high, even in the absence of previously documented laboratory-associated infections (e.g., exotic arboviruses); or the consequences of infection are grave.
Recommendations for the use of vaccines and toxoids are included in agent summary statements when such products are available, either as licensed or Investigational New Drug (IND) products (see Appendix B, Immunoprophylaxis). When applicable, recommendations for the use of these products are based on current recommendations of the Public Health Service Advisory Committee on Immunization Practice, and are specifically targeted to at-risk laboratory personnel and others who must work in or enter laboratory areas. These specific