The Efficacy and Safety of Topical Microbicide Gels to Prevent Sexual Transmission of Human Immunodeficiency Virus (HIV) Infection: a Systematic Review and Meta-analysis

Background: Topical microbicide gels are a potential method to reduce sexually transmitted human immunodeficiency virus (HIV) infection, especially in women. Several randomized controlled trials (RCTs) of topical microbicides to prevent HIV transmission have yielded promising results, however trial results have been inconsistent. The objective of this study was to determine the efficacy and safety of topical microbicide gels to prevent HIV transmission.Methods: We conducted meta-analyses, stratified by microbicide gel type, using a random-effects model. We included 25 RCTs that met the inclusion criteria: 13 RCTs examined gel efficacy during heterosexual contact, and an additional 12 trials reported on gel acceptability, participants’ adherence to intervention, and adverse reactions (allergic reaction and pain). Results: With this limited data, topical microbicide gels were not found to be significantly better than placebo in preventing HIV infection (risk ratio (RR) 0.93, 95% CI 0.82 to 1.04; I2 14%; 13 trials; 31,764 participants). It should be noted that low adherence rates were frequently reported within trials. In one trial with high participant adherence (>70%) to intervention, there was a significant protective effect of gels (RR 0.63, 95% CI 0.43 to 0.93; 889 participants). While measures of acceptability and adherence to intervention were similar between groups, administration of topical microbicides were associated with an increased incidence of pain at the application site (RR 1.16, 95% CI 1.00 to 1.36, I2 0%, 15 trials, 19,554 participants).Conclusions: In conclusion, efficacy of topical microbicide gels may relate to baseline risk and compliance with the intervention. In the general population it is not associated with protection from sexually transmitted HIV infection.