Engaging in unprotected anal or vaginal sex is considered to pose the greatest risk of infection with HIV due to the biological and physical factors involved in these types of sexual activity. During unprotected sex, particularly anal sex, the risk of HIV is heightened because the rectal tissues are more susceptible to tearing, allowing the virus easier access into the bloodstream.
Moreover, vaginal tissues can also be vulnerable to micro-tears during intercourse, especially if lubrication is insufficient. This risk is compounded when one partner is HIV-positive and the other is HIV-negative, facilitating the transmission of the virus directly through bodily fluids such as semen, vaginal secretions, or blood.
In contrast, using protection during sex significantly reduces the risk of HIV transmission by providing a barrier that prevents the exchange of these bodily fluids. While having multiple sexual partners can increase exposure risk, the key factor is whether protection is used; thus, it does not directly correlate to a higher risk than unprotected sex. Sharing food utensils does not pose a risk for HIV transmission, as the virus does not survive long outside the body and is not transmitted through casual contact or shared items.
Therefore, the activity identified as the greatest risk is unprotected anal or vaginal sex, highlighting the importance of safe sex practices