Antiretrovirals Work Even With Low Viral Loads.

CHICAGO -- Even among women with low viral loads, standard antiretroviral prophylactic therapy provides as much as a 90% reduction in the risk of perinatal HIV transmission, Dr. John P.A. loannidis said at a conference on retroviruses and opportunistic infections.

In a metaanalysis of seven studies conducted in the United States and Europe, 1,202 women had HIV-1 RNA levels of less than 1,000 copies/mL at or close to the time of delivery; only 8 of 834 (1%) who took antiretroviral therapy transmitted the virus to the infant.

By contrast, perinatal HIV transmission occurred in 36 of the 368 (9.8%) cases in which the expectant mother did not take prophylactic antiretroviral therapy.

A cesarean section also was identified in a multivariate analysis as providing an additional 70% risk reduction. There were no transmissions among 270 women who took antiretroviral therapy and had a C-section. By comparison, 5 of 66 patients(7.6%) who did not take antiretroviral therapy but who had a C-section transmitted the virus to their infant. Distinctions between women who had elective and nonelective C-sections could not be determined from the data, explained Dr. Ioannidis of the University of Ioannina (Greece).

The risk of perinatal transmission also dropped 12% for every 100 cells in the CD4 count.

"We are on the verge of the virtual elimination of HIV perinatal transmission in research-rich centers. The last 7 years have seen remarkable strides in perinatal HIV prevention research," commented Dr. Mary Glenn Fowler of the Centers for Disease Control and Prevention, Atlanta.

Before findings from the landmark 1994 study known as the AIDS Clinical Trials Group (ACTG) 076, perinatal transmission rates were about ...