Effectiveness of vaginal microbicides in preventing HIV transmission.

Musekiwa, Alfred; Fernando, Nimasha B; Abariga, Samuel A

OBJECTIVE To evaluate the evidence on the effectiveness of vaginal microbicides in preventing HIV transmission in women. METHODS Systematic review through a comprehensive search of relevant electronic databases for eligible randomized controlled trials (RCTs) published through June 2019. Two authors independently screened titles and abstracts according to eligibility criteria, then extracted data and assessed risk of bias of included studies. We conducted a random effects meta-analysis of risk ratios (RR) of HIV infection and assessed heterogeneity using Chi2 and I2 tests. Sources of heterogeneity were investigated through subgroup analysis, publication bias was assessed using funnel plots, and certainty of evidence was graded using GRADEPro software. RESULTS We included 18 RCTs which enrolled 40,048 sexually-active, HIV-negative, non-pregnant women, aged 16 years and older, mainly from sub-Saharan Africa. The intravaginal ring containing Dapivirine significantly reduced HIV risk by 29% (RR 0.71, 95%CI:0.57-0.89; 2 RCTs, 4,564 women, moderate certainty of evidence). Estimates of effect of Tenofovir 1% (RR 0.83, 95%CI:0.65-1.06), Nonoxynol-9 (RR 1.15, 95%CI:0.93-1.42), cellulose-sulphate (RR 1.16, 95%CI:0.61-2.21), SAVVY (RR 1.34, 95%CI:0.69-2.59), Carraguard (RR 0.89, 95%CI:0.71-1.10), BufferGel (RR 1.02, 95%CI:0.71-1.46), 0.5% PRO2000 (RR 0.88, 95%CI:0.60-1.28) and 2% PRO2000 (RR 0.81, 95%CI:0.58-1.12) failed to reach statistical significance; each had low certainty of evidence. CONCLUSION The long-acting intravaginal ring containing Dapivirine significantly reduced risk of HIV transmission in women by 29%. The remaining microbicides had no evident effect.