Preventing HIV transmission from mother to child in sub-Saharan Africa may be cheaper and easier than previously thought, according to researchers in the United States and Uganda.

The researchers used a computer model to evaluate the cost-effectiveness of using nevirapine, an antiviral drug that recently showed remarkable reductions of HIV transmission from mother to child. The nevirapine regimen was significantly cheaper and more effective than three similar drug treatments that have recently been tested. The study results appear in the current issue of The Lancet.

"Identifying economical interventions to reduce the ongoing devastation of AIDS is an urgent public health priority," said James G. Kahn, MD, MPH, UCSF professor of epidemiology and biostatistics, AIDS Research Institute, Institute for Health Policy Studies, and co-author of the paper. "Our study shows that reducing HIV transmission from mother to child in developing countries is economically feasible. It lends strong support to HIV prevention efforts."

HIV has infected three million children since the pandemic began, and 90 percent of them have been born in Africa. Although long-term treatment with the antiviral drug AZT is the most effective way to prevent HIV transmission in industrial countries like the United States, it is expensive and must be started early in pregnancy. Most African mothers cannot afford AZT and often do not get prenatal care, thereby missing their chance to begin treatment.

To address the needs of developing countries, scientists have developed more feasible and less expensive "short-course" drug regimens that can be started late in pregnancy. All involve different doses and timing of antiviral drugs. The newest treatment uses nevirapine and has recently been tested in a clinical trial called HIVNET 012. The nevirapine regimen resulted in almost 50 percent fewer HIV cases in infants compared to a short-course AZT treatment. Results of the trial are also published in the current issue of The Lancet.

"The results were pretty stunning," said Elliot Marseille, DrPH, MPP of Health Strategies International and lead author of the study. "We wanted to find out how cost-effective nevirapine would be, given the remarkable transmission reduction observed in just one dose to mother and child." The researchers built a computer model to compare five short-course drug programs: HIVNET 012 universal, assuming that all pregnant women were offered nevirapine; HIVNET 012 targeted, assuming women were counseled and tested for HIV prior to treatment; an AZT trial sponsored by the Centers for Disease Control; and trials sponsored by UNAIDS that tested a combination of AZT and the antiviral drug lamivudine administered late in pregnancy (PETRA, Arm-A) and at labor (PETRA, Arm-B).

The model assumed each treatment program was given to 20,000 hypothetical pregnant women in sub-Saharan Africa. It took into account various factors such as rates of HIV infection, breastfeeding habits, life expectancies, and effectiveness of the treatment. All of these variables were derived from current literature, said Marseille.

The nevirapine programs produced the most health benefit for the dollar by a wide margin, said Marseille. The universal nevirapine program cost approximately $80,000 a year, assuming 30 percent of the population was infected with HIV, and prevented 603 infections during the hypothetical 12 month period. This was about one-tenth the cost of the most expensive treatment, the AZT/lamivudine trial begun during pregnancy, which cost nearly $900,000 and prevented 315 HIV infections. The targeted nevirapine program was the second cheapest and effective, costing $140,000 a year and preventing 476 HIV infections.

Of even greater significance were the relative costs of averting one case of infant HIV. The cost to prevent one HIV infection using the universal nevirapine treatment was $138, again the best option by a wide margin. The targeted nevirapine treatment was the next closest at $298 followed by CDC-AZT ($1,103), PETRA-B ($1,304), and PETRA-A ($2,809).

"The HIVNET 012 regimen is cheap, effective, and easy to administer," said Marseille. "The key finding of this analysis is that the HIVNET 012 protocol is likely to be cost-effective in both targeted and universal treatment options in much of sub-Saharan Africa, regardless of infection rates." In addition to Marseille and Kahn, co-authors include Francis Mmiro, MBChB, FRCOG, professor of obstetrics and gynecology, Makerere University, Uganda; Laura Guay, MD, professor of pathology, Johns Hopkins University School of Medicine; Philippa Musoke, MBChB, professor of pediatrics, Makerere University, Uganda; Mary Glenn Fowler, MD, HIV/AIDS Branch, Centers for Disease Control and Prevention; and J. Brooks Jackson, MD, professor of pathology, Johns Hopkins University School of Medicine.