Prevention is key in addressing incurable STIs, such as HIV & herpes. Sexual health clinics fight to promote the use of condoms and provide outreach for at-risk communities.
The most effective way to prevent sexual transmission of STIs is to avoid contact of body parts or fluids which can lead to transfer with an infected partner. Not all sexual activities involve contact: cybersex, phonesex or masturbation from a distance are methods of avoiding contact. Proper use of condoms reduces contact and risk. Although a condom is effective in limiting exposure, some disease transmission may occur even with a condom.
Ideally, both partners should get tested for STIs before initiating sexual contact, or before resuming contact if a partner engaged in contact with someone else. Many infections are not detectable immediately after exposure, so enough time must be allowed between possible exposures and testing for the tests to be accurate. Certain STIs, particularly certain persistent viruses like HPV, may be impossible to detect with current medical procedures.
Many diseases that establish permanent infections can so occupy the immune system that other diseases become more easily transmitted. The innate immune system led by defensins against HIV can prevent transmission of HIV when viral counts are very low, but if busy with other viruses or overwhelmed, HIV can establish itself. Certain viral STI's also greatly increase the risk of death for HIV infected patients.
Vaccines
Vaccines are available that protect against some viral STIs, such as Hepatitis A, Hepatitis B, and some types of HPV. Vaccination before initiation of sexual contact is advised to assure maximal protection.
Condoms
Condoms and female condoms only provide protection when used properly as a barrier, and only to and from the area that it covers. Uncovered areas are still susceptible to many STDs. In the case of HIV, sexual transmission routes almost always involve the penis, as HIV cannot spread through unbroken skin, thus properly shielding the insertive penis with a properly worn condom from the vagina or anus effectively stops HIV transmission. An infected fluid to broken skin borne direct transmission of HIV would not be considered "sexually transmitted", but can still theoretically occur during sexual contact, this can be avoided simply by not engaging in sexual contact when having open bleeding wounds. Other STDs, even viral infections, can be prevented with the use of latex, polyurethane or polyisoprene condoms as a barrier. Some microorganisms and viruses are small enough to pass through the pores in natural skin condoms, but are still too large to pass through latex or synthetic condoms.
Proper usage entails:
Not putting the condom on too tight at the end, and leaving 1.5 cm (3/4 inch) room at the tip for ejaculation. Putting the condom on snug can and often does lead to failure.
Wearing a condom too loose can defeat the barrier.
Avoiding inverting, spilling a condom once worn, whether it has ejaculate in it or not.
Avoiding condoms made of substances other than latex, polyisoprene or polyurethane that do not protect against HIV.
Avoiding the use of oil based lubricants (or anything with oil in it) with latex condoms, as oil can eat holes into them.
Using flavored condoms for oral sex only, as the sugar in the flavoring can lead to yeast infections if used to penetrate.
Not following the first five guidelines above perpetuates the common misconception that condoms are not tested or designed properly.
In order to best protect oneself and the partner from STIs, the old condom and its contents should be assumed to be infectious. Therefore the old condom must be properly disposed of. A new condom should be used for each act of intercourse, as multiple usage increases the chance of breakage, defeating the effectiveness as a barrier.
Nonoxynol-9
Researchers had hoped that nonoxynol-9, a vaginal microbicide would help decrease STD rates. Trials, however, have found it ineffective. In fact, the use of nonoxynol-9 can put women at a higher risk of HIV infection.