Into Groups 1, 2, 3 and 4, according to their potential effect on humans.
A Group 1 biological agent is one that is unlikely to cause human disease. A Group 2 biological agent is one that can cause human disease and might be a hazard to workers but is unlikely to spread to the community and for which there is usually an effective prophylaxis or treatment available. A Group 3 biological agent is one that can cause severe human disease, presents a serious hazard to workers and may present a risk of spreading to the community but for which there is usually an effective prophylaxis or treatment available. A Group 4 biological agent is one that causes severe human disease, is a serious hazard to workers and may present a high risk of spreading to the community and for which there is usually no effective prophylaxis or treatment available.
