BACKGROUND

In resource-limited settings, mothers infected with human immunodeficiency virus type 1 (HIV-1) face a difficult choice: breastfeed their infants but risk transmitting HIV-1 or not breastfeed their infants and risk the infants dying of other infectious diseases or malnutrition. Recent results from observational studies and randomized clinical trials indicate daily administration of nevirapine to the infant can prevent breast-milk HIV-1 transmission.

METHODS

Data from 5396 mother-infant pairs who participated in 5 randomized trials where the infant was HIV-1 negative at birth were pooled to estimate the efficacy of infant nevirapine prophylaxis to prevent breast-milk HIV-1 transmission. Four daily regimens were compared: nevirapine for 6 weeks, 14 weeks, or 28 weeks, or nevirapine plus zidovudine for 14 weeks.

RESULTS

The estimated 28-week risk of HIV-1 transmission was 5.8% (95% confidence interval [CI], 4.3%-7.9%) for the 6-week nevirapine regimen, 3.7% (95% CI, 2.5%-5.4%) for the 14-week nevirapine regimen, 4.8% (95% CI, 3.5%-6.7%) for the 14-week nevirapine plus zidovudine regimen, and 1.8% (95% CI, 1.0%-3.1%) for the 28-week nevirapine regimen (log-rank test for trend, P < .001). Cox regression models with nevirapine as a time-varying covariate, stratified by trial site and adjusted for maternal CD4 cell count and infant birth weight, indicated that nevirapine reduces the rate of HIV-1 infection by 71% (95% CI, 58%-80%; P < .001) and reduces the rate of HIV infection or death by 58% (95% CI, 45%-69%; P < .001).

CONCLUSIONS

Extended prophylaxis with nevirapine or with nevirapine and zidovudine significantly reduces postnatal HIV-1 infection. Longer duration of prophylaxis results in a greater reduction in the risk of infection.