^*Factors that may increase the risk of HIV transmission include sexually transmitted diseases, acute and late-stage HIV infection, and high viral load. Factors that may decrease the risk include condom use, male circumcision, antiretroviral treatment, and preexposure prophylaxis (PrEP). None of these factors are accounted for in the estimates presented in the table.

^{^}HIV transmission through these exposure routes is technically possible but unlikely and not well documented.