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

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.

Perinatal HIV transmission: developing country considerations

In many developing countries, because the prevalence of maternal HIV infection is high (more than 30% in some sub-Saharan African countries) and the resources commonly used to prevent transmission in developed countries are generally not available, transmission of HIV from mother to infant is a devastating problem. Countries already experiencing infant mortality rates 10- to 20-fold greater than those in developed countries can expect a doubling of infant and childhood mortality due to HIV. Those infants who escape infection themselves can expect to be orphaned in early childhood. Low-cost antiviral therapy can reduce transmission substantially, but many countries do not have the infrastructure to screen pregnant women for HIV and appropriately treat the mothers and infants. In developing countries, reduction in maternal-child transmission is feasible, but will require substantial additional resources and a well-functioning obstetric care system.

Effect of nevirapine toxicity on choice of perinatal HIV prevention strategies

OBJECTIVES

This study evaluated the validity of concerns about the toxicity of nevirapine (NVP) that have delayed its implementation as a perinatal HIV prevention strategy.

METHODS

A decision analysis model compared 3 strategies: single-dose NVP, short-course zidovudine (ZDV), and no intervention.

RESULTS

NVP would prevent more deaths than ZDV and no intervention as long as the rate of NVP toxicity did not exceed, respectively, 9 times that observed in the earlier NVP clinical trial and 42 times that observed in the clinical trial. NVP would be economically preferable to ZDV as long as the rate of toxicity did not exceed 22 times that observed in the clinical trial.

CONCLUSIONS

Field implementation of NVP should not be delayed by concerns about its toxicity.