To our knowledge, this is the first report of universal administration of NVP to women of unknown HIV status upon presentation in labor. We found the strategy to be acceptable to a substantial minority of women (40%) and to result in near perfect adherence to the intervention. Furthermore, this study validates HPLC of cord blood as an extremely sensitive measure of NVP adherence, as the drug was detectable in all but a single woman observed to have ingested it.
These data strongly suggest that universal NVP at the labor ward can result in significant reduction of MTCT. First, we observed a transmission rate that is in line with other published reports of NVP efficacy [11
]. Second, when compared with an untreated, contemporaneous control group from the same birthing centers, we observed a 42% relative reduction in transmission risk. Unfortunately, we do not have data available on the control population to allow careful assessment of its comparability to our study cohort (e.g. CD4 cell count, viral load). However, the rate of transmission at 4–6 weeks of infant life observed in the control population was very similar to that observed in numerous other untreated cohorts [13
]. Given the prevalence of HIV in our population (29%) and observed efficacy (42%), we can calculate that one would need to treat about 41 mother–infant pairs of unknown HIV status with NVP in order to prevent one infant infection (number needed to treat = 41). As single dose intra-partum and neonatal NVP prevents an infection that is essentially universally fatal, it would have to be fatally toxic in 2.4% of cases in order for its benefit to be negated by its risks.
These data make several important points. Labor ward administration of NVP to women of unknown HIV serostatus is acceptable to a substantial minority of women. It could be argued that active labor is not the best time for women to be asked to make a decision about NVP, and indeed this may explain why more than half of women declined to participate. However, the choice whether to take NVP in labor does not differ in risk–benefit complexity than myriad other decisions that women make in labor (e.g. whether to undergo cesarean delivery). A major benefit of labor-ward-based therapy is that it is directly observed, and thus adherence is considerably better than if the drug is issued to patients in antenatal care for self-administration at labor onset [5
There are several arguments against the use of this approach in systems that can support more sophisticated services in antenatal care. First, women who for whatever reason do not deliver at an obstetric facility are unable to access the medication. Second, we noted very low rates of VCT uptake at postnatal visits. Since we cannot verify how thoroughly our study staff advocated testing at postnatal visits, we cannot state that our low subsequent VCT rates are generalizable to other settings. They are, however, clearly sub-optimal. Third, labor ward administration almost certainly results in later timing of the maternal dose compared with the dosing at the onset of labor – an effect that may work to diminish the prophylactic efficacy of NVP [14
Thus, although universal labor-ward-based NVP may be inferior to other approaches as a primary PMTCT strategy, it still may be appropriate in two very important circumstances: (1) as an emergency or interim measure in settings where fully-fledged PMTCT services are unavailable, and (2) as an adjunctive approach to an antenatal-based program in order to reach those women who might have been missed previously or who might have failed to take their NVP as planned. In such a role, universal labor-ward-based NVP would be very likely to improve the population coverage of the drug. Indeed, even in settings in which a well-functioning antenatal PMTCT program is in place, offering NVP to all women presenting in labor, unless they have a documented negative HIV result, will be likely to save lives when background HIV seroprevalence rates are high. Although such an approach may result in double dosing of some women, the overall dose in such cases (400 mg) would not exceed the daily dose for adults on chronic NVP therapy and would be unlikely to add viral resistance concerns beyond those already extant. Given the negligible risks of single-dose NVP to HIV-uninfected women and their infants, a compelling rationale can be made for the addition of a labor ward NVP component to PMTCT programs in areas of high HIV prevalence. This component could, with high cost effectiveness, save many infant lives.