This is the term for the classification of cases that summarizes a person’s possible HIV risk factors; the summary classification results from selecting, from the presumed hierarchical order of probability, the one risk factor most likely to have resulted in HIV transmission. The exception is men who had sexual contact with other men and injected drugs; this group makes up a separate transmission category.
Persons whose transmission category is classified as male-to-male sexual contact include men who report sexual contact with other men (i.e., homosexual contact) and men who report sexual contact with both men and women (i.e., bisexual contact).
Persons whose transmission category is classified as injection drug use (IDU) are persons who injected non-prescribed drugs.
Persons whose transmission category is classified as heterosexual contact are persons who have ever had specific heterosexual contact with a person known to have, or to be at high risk for, HIV infection (e.g., a person who injects drugs).
All other transmission categories have been collapsed into “Other.” The “Other” transmission category includes: hemophilia, blood transfusion, perinatal exposure, and risk factor not reported or not identified.