Comparison of two strategies for administering nevirapine to prevent perinatal HIV transmission in high-prevalence, resource-poor settings

Abstract

Universal nevirapine (NVP) therapy (provision of the drug without HIV testing) has been suggested as potentially superior to targeted NVP therapy (provision of the drug to seropositive patients identified through voluntary HIV counseling and testing [VCT]) for perinatal HIV prevention in low-resource, high-prevalence settings. The authors postulated that uptake (the proportion of women who accept the strategy when offered) may be higher for universal therapy, since it does not require a woman to learn her serostatus; they further postulated that adherence (the proportion of women who actually ingest the NVP tablet at labor onset) may be higher for targeted therapy, since knowledge of serostatus could motivate better adherence. Two clinics in Lusaka, Zambia were assigned to provide either the targeted or universal strategy. Halfway through the study period, the approach offered at each clinic was crossed over. Adherence was assessed by liquid chromatographic assay for NVP of cord blood. Regarding uptake, 1524 pregnant women were offered participation, and 1025 (67%) accepted. Of 694 women offered enrollment in the universal strategy, 496 (71%) accepted; of 830 women offered enrollment in the targeted strategy, 529 (64%) accepted (p <.01). Uptake was similar at both clinics for the universal strategy: 250 of 339 (74%) at clinic A and 246 of 355 (69%) at clinic B (p =.2), but differed significantly between clinics for the targeted strategy: 229 of 316 (72%) at clinic A and 300 of 514 (58%) at clinic B (RR, 1.51; 95% CI, 1.23, 1.86). Increased uptake correlated with having been offered the universal rather than the targeted strategy (AOR, 1.5; 95% CI, 1.1, 2.1), attendance at clinic A (AOR, 1.4; 95% CI, 1.01, 2.0), and maternal report of a prior fetal or infant death (AOR, 1.6; 95% CI, 1.1, 2.5). Regarding adherence, in the universal strategy, 40 of 103 women (39%) were nonadherent compared with 25 of 98 women (26%) in the targeted strategy (RR, 1.5; 95% CI, 1.004, 2.3). Failure to adhere correlated with participation in the universal strategy (AOR, 2.0; 95% CI, 1.04, 4.2) and illiteracy (AOR, 2.6; 95% CI, 1.2, 5.3). In high-prevalence settings with adequate VCT services, uptake of NVP using the universal or targeted approach appears comparable. However, the universal strategy may result in better uptake in clinics with less well-functioning VCT services (as with clinic B). Adherence to the single-dose NVP intervention was lower among women who did not learn their HIV status. Programs that seek to save the greatest possible number of infants from perinatal HIV acquisition should consider a combination approach, in which women who desire HIV testing can access NVP through a targeted strategy, and women who do not desire testing can access NVP through a universal strategy.

FIG. 1

Trial profile: *371 HIV-uninfected women in the universal arm were followed in the study, but their cord blood was not assayed for NVP, and they are not reported on here. †Composite adherence outcome includes those from whom cord blood specimens were available plus those who returned their NVP tablet plus (in the targeted group only) and two patients from whom cord blood specimens were missing but in whom NVP ingestion was directly observed by study staff.