Risk is greatest if no barrier device is used and if menstrual or other blood is present. Fellatio with a condom is a low risk behavior. Risk for both partners increases if no condom is used. Greatest risk if no condom is used and ejaculate gets into mouth, although HIV may be present in pre-ejaculate as well. Correct and consistent use of condoms with sufficient vaginal lubrication is low risk.
Unprotected intercourse is the riskiest sexual behavior.
Unprotected anal intercourse is highest risk sexual behavior. Unprotected oral-anal contact involves risk for contact with a host of pathogenic organisms. Sharing injection drug needles is extremely high risk behavior. There are needle exchange sites in San Francisco, Oakland and Berkeley. Risk of contracting HIV is greatly reduced if both partners have tested for HIV antibodies twice over a six month period with negative results and do not have risky sex with others.