| Exposure categories | HIV/AIDS and hepatitis C exposure categories refer to the most likely way a person became infected with the virus, that is, the most likely route of transmission. | 
| Notification1 | Confidential reporting by a doctor or other health care provider of the diagnosis of a specific condition such as HIV infection to their local public health unit, as required by the law. | 
| Prevalence2 | Prevalence is a frequently used measure of how commonly a disease or condition occurs in a population. Prevalence measures how much of some disease or condition there is in a population at a particular point in time. | 
| Incidence3 | The incidence of a disease is another measure. Incidence measures the rate of occurrence of new cases of a disease or condition. |