A meta-analysis of condom effectiveness in reducing sexually transmitted HIV

Abstract

An earlier meta-analysis of condom use among HIV serodiscordant couples found that condom use reduces the risk of HIV transmission by 69%. The study design had a methodological flaw however which negates the conclusion that condoms should be a secondary strategy in HIV prevention. The investigator inappropriately combined studies with very different measures of condom use. Specifically the studies examined user failure and method failure yet the investigator blamed method failure (i.e. failures despite correct condom use with every act of intercourse) as the reason for all HIV seroconversions. He should have used only studies measuring consistent condom use for every coital act (i.e. always or 100% vs. any other use) to reliably determine method failure. In fact only 2 of the 11 studies in the meta-analysis met this criterion. These 2 studies revealed that none of the 20 consistent condom users seroconverted while 20% of inconsistent or nonusers did. Rather than being a study of condom effectiveness the meta-analysis was a study of inconsistent use (i.e. somewhat inconsistent condom use vs. more inconsistent condom use). Thus its only conclusion is that couples who use condoms more consistently had a 1/3 lower risk of HIV transmission than did those who used condoms less often. This conclusion stresses the importance of consistent and correct condom use. Two recent prospective studies examining always use and not always/never use confirm the increased protection of consistent and correct condom use (HIV seroconversion rates 0 vs. 10% and 2% vs. 15%). Latex condoms do not eliminate all risk of HIV transmission but when couples who engage in sexual intercourse use them consistently and correctly condoms significantly reduce the risk of HIV transmission. The 69% misleading condom effectiveness rate in the article has caused unjustified skepticism. Condom use should be encouraged.