Reuse of single-dose nevirapine in subsequent pregnancies for the prevention of mother-to-child HIV transmission in Lusaka, Zambia: A cohort study

We compared risks of perinatal HIV transmission between multiparous women who had previously received a dose of SDNVP (exposed) and those that had not (unexposed) and who were given SDNVP for the index pregnancy within a PMTCT clinical study. We also compared transmission risks among exposed and unexposed women who had two consecutive pregnancies within the trial. Logistic regression modeling was used to adjust for possible confounders.Transmission risks did not differ between 59 SDNVP-exposed and 782 unexposed women in unadjusted analysis or after adjustment for viral load and disease stage (adjusted odds ratio 0.6, 95% confidence interval [CI] 0.2 to 2.0). Among 43 women who had two consecutive pregnancies during the study, transmission risks were 7% (95% CI 1% to 19%) at both the first (unexposed) and second (exposed) delivery. The results were unchanged, if infant death was included as an outcome.These data suggest that the efficacy of SDNVP may not be diminished when reused in subsequent pregnancies.Single-dose nevirapine (SDNVP) given at the onset of labor to the mother and within 72 hours of birth to the infant is a safe, efficacious, simple and cost-effective intervention for the prevention of mother-to-child HIV transmission (PMTCT) [1]. It has been widely implemented in resource-constrained countries, where more complex and potent regimens are not available [2].A drawback of this regimen is the selection of resistance mutations in a large proportion of exposed women and their infected infants [2]. These mutations may reduce virologic susceptibility to treatment with non-nucleoside reverse transcriptase inhibitor-based regimens if initiated soon after delivery [3,4]. The mutations may also remain detectable in a small proportion of women at above pre-exposure levels as late as 1 year post-partum [5-7], raising concerns that use of this regimen for PMTCT in subsequent pregnancies compromises the efficacy of the intervention.Studies from South Africa/Cote d'I