Doctors have long suspected that AZT might lower the risk of mother-to-child transmission, by reducing the amount of virus in a woman’s blood. But lacking hard evidence-and fearing that AZT might harm a developing fetus-they’ve reserved the drug for women who need it to combat their own advanced illness. In the new study, researchers in the United States and France went a step further. From 1991 to 1993, they identified 477 pregnant women who were HIV-positive but still healthy. Half took AZT during pregnancy, labor and delivery, while the other half took a placebo. When the babies were born, they got an additional six weeks of whatever treatment their mothers had received.
Last December, a panel of independent experts reviewed preliminary data from the study, and they were stunned by what they saw. Of the 364 babies who had been tested for HIV, 53 were infected-and 40 of the 53 came from women who hadn’t received AZT Only 8 percent of the AZT babies had contracted HIV, versus 25 percent in the placebo group; mild anemia was the treatment’s only apparent side effect. The researchers had planned to collect data on 748 pregnancies. But in light of the treatment’s success, they have now stopped enrolling new patients and started offering AZT to all those still taking placebo. The National Institute of Allergy and Infectious Disease, which sponsored the study, is alerting doctors to the finding.
Worldwide, more than 200,000 babies are born with HIV every year. If the new study is any indication, AZT could lower that number substantially. But the encouraging findings don’t presage an end to childhood AIDS, or even a two-thirds reduction in new cases. For one thing, the researchers treated carefully selected patients under ideal circumstances. There’s no reason to assume that all infected women would respond the same way. Even if they did, getting the drug to all who need it would remain a daunting challenge. Few people in the developing world can spend $50 a week on AZT, regardless of whether they’re pregnant. And because pregnant women are not routinely tested for HIV in the United States, many of those who could now spare their children still pass on the virus unknowingly. Dr. Rhoda Sperling of New York, who codirected the new study, predicts it will “put pregnancy testing policies back on the front burner.” That would be an accomplishment in itself.
