Dear Dr.

Congratulations for you great job in this web site and in your organization.

Im a brazilian guy and im curious to know why there are differences between the risk of contracting HIV from insertive oral sex and kissing.I always thought this exposures had the same factors like saliva that is not infectious and mucous membranes. So, why the differences. Why cant we say that the risk of contracting HIV for this kinds of exposures are the same?

Sorry about my poor English, im studyng to improve it.

By the way, i know that you aprecciate a good world music so i think that you must enjoy Bossa Nova.

Thank You Very Much

Hello Brazilian Guy!

The first and most important thing to point out is that the HIV risk of insertive oral sex is extremely low and the risk of HIV transmission from kissing is essentially nonexistent, unless there are extenuating circumstances that would increase the risk for either of these activities. Consequently, the difference in risk between these two activities is extremely minimal. The factors that account for this minimal difference are primarily physiological and biological. For example, the mucous membrane of the urethra is more fragile than the mucous membrane of the mouth. Therefore it is more prone to damage, thereby possibly allowing HIV additional access into the body. Also, insertive oral sex is often a more "vigorous" activity than a smooch. The thrusting in close proximity to the teeth increases the risk that the delicate urethral mucous membrane could be traumatized. Finally, the saliva covering the oral mucosa membranes does have some anti-HIV effect.

Bossa Nova? Absolutely! Who can resist its spunky up-tempo beat and fancy footwork! By the way, your English is way better than my Bossa Nova!

Stay safe. Stay well.

Dr. Bob