The provision of antiretroviral therapy to women at the onset of labour and for a short period postnatally to the infant is thought to be sufficient to decrease vertical transmission around the time of childbirth and the start of breastfeeding. This might offer a more affordable approach for HIV-1 infected pregnant women in less-developed countries. The HIVNET 012 study team reported in 1999 that a single-dose intrapartum and neonatal nevirapine regimen significantly decreased the risk of transmission of HIV-1 from mother to child by 47% compared with a short intrapartum/neonatal zidovudine regimen when 87% of babies in the trial had reached age 14-16 weeks. The same investigators led by Brookes Jackson from Makerere University-Johns Hopkins University Research Collaboration (part of the NIH funded HIV Prevention Trials Network) report the safety and efficacy of the nevirapine regimen in all study mothers up to six weeks after delivery and for all babies up to 18 months of age.
From late 1997 to early 1999, HIV-1 infected pregnant women in Kampala, Uganda, were randomly assigned nevirapine (200 mg at labour onset and 2 mg/kg for babies within three days of birth) or zidovudine (600 mg orally at labour onset and 300 mg every 3 hours until delivery, and 4 mg/kg orally twice daily for babies for 7 days). Infant HIV-1 testing was done at birth, age 6-8 and 14-16 weeks, and age 12 months.
645 mothers were enrolled in the study, half received nevirapine, the other half received zidovudine. 99% of babies were breastfed for an average of nine months. Infants were around 40% less likely to have had maternal HIV-1 infection up to 18 months of age if mothers and infants had been given nevirapine around the time of childbirth compared with those given zidovudine.
Brooks Jackson comments: "The absolute 8.2% reduction in transmission at 6-8 weeks was sustained at age 18 months...This simple, inexpensive, well-tolerated regimen has the potential to significantly decrease HIV-1 perinatal transmission in less-developed countries."
In an accompanying Commentary (p 842), x from y cautions against the widespread use of single-dose agents such as nevirapine because of the potential for resistance to develop against other similar antiretroviral drugs. She concludes: 'Generic antiretrovirals, prepared in convenient single-pill triple combinations for once and twice daily dosing, are now available for less than US$1 a day. The HIVNET 012 protocol was modified in 1998 to accommodate the changing realities of the HIV-1 pandemic. 5 years later, these realities have shifted yet again. Suboptimum single-agent and double-agent prophylaxis protocols no longer have a justifiable place in the front lines of the global struggle against HIV/AIDS. It is up to all of us to focus on development of equitable distribution and effective use of these agents now. Once they are widely available, it may be too late.'
Dr. Brooks Jackson, Department of Pathology, Johns Hopkins University, 600 N Wolfe Street / Carnegie 420, Baltimore, MD 21287-6417, USA; T): 1-410-614-4966; F): 1-410-614-2907; E): BJACKSO@jhmi.edu.
Dr. Karen Palmore Beckerman, Bellevue Hospital Center, New York University School of Medicine, NY 10016, USA; E) Karen.Beckerman@msnyuhealth.org.