How effective are condoms in preventing STIs?
Condom breakage and slippage is estimated to occur 1-4% of the time. This is known as method failure. By far the most extensive research on condom effectiveness has been done for HIV. A number of authors have performed meta-analyses (summaries) of other studies. These meta-analyses show that with 100% consistent condom use, condoms reduce the risk of HIV transmission by about 85%. Condom effectiveness against transmission of bacterial diseases like gonorrhea, chlamydia and syphilis is significantly lower than for HIV. Conclusive evidence is lacking for condom effectiveness against transmission of several other specific STIs, such as HPV and T. vaginalis, which each affect over 5 million people annually. Finally, effectiveness is seriously limited for the many STIs which are transmitted through skin-to-skin contact, since condoms do not cover all the areas of the body which may be the source of transmission. The major factor affecting “condom effectiveness” is not method failure, over w
