U.S. doctors have a responsibility to tell HIV-infected pregnant women that the drug AZT can dramatically reduce the chances that their babies will be born with the fatal virus, according to new U.S. guidelines.
But the final decision about taking AZT should be left to the women, the guidelines say.
The guidelines, issued here at the 10th International AIDS Conference, stem from a recent U.S. government study that found that AZT, if taken during pregnancy and labor, can reduce by two-thirds the risk that a mother will transmit the AIDS virus to her newborn.
The finding, reported by government researchers in February, is one of the few pieces of good news in more than a decade of AIDS research. It has buoyed the hopes of many among the 11,000 participants in the weeklong conference here.
“The onus is on the health-care system,” Dr. David Satcher, director of the U.S. Centers for Disease Control and Prevention, said during a news briefing.
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“From our perspective, these findings say very clearly to (health-care) providers that you have a mechanism for significantly reducing the risk of transmission of HIV from mother to child,” Satcher said.
The guidelines, which are advisory but carry the weight of the nation’s public-health establishment, are aimed at reducing the 1,750 U.S. babies born each year with the human immunodeficiency virus, which causes acquired immune deficiency syndrome.
Barring an unexpected breakthrough in research, an HIV-infected baby is destined to die, usually before reaching puberty.
Worldwide, 350,000 infants were born with HIV last year, most of them in developing countries, according to the Harvard School of Public Health.
Although the guidelines apply only to the United States, federal officials and those from the World Health Organization said that they were exploring the possibility of clinical trials of AZT, or possibly other drugs, among HIV-infected pregnant women in Third World countries.
These trials could start within a year, officials said.
While many women in developing countries are eager for AZT, “right now it is not affordable,” said Ruth Nduati, a pediatrician who works with HIV-infected women in Nairobi, Kenya.
AZT is hardly a cure, and there are many unanswered questions about it. It is not known, for instance, whether babies given AZT will eventually develop abnormalities or whether mothers who take AZT will develop a virus resistant to the drug.
But the recent U.S. government study among 463 HIV-positive women found that AZT appeared to be safe for mother and child and appeared to reduce dramatically viral transmission: Only 8 percent of the babies born to mothers who took AZT were infected, compared with 26 percent of the babies born to mothers who got a placebo.
The women were given AZT orally during part of their pregnancy and then intravenously during labor. Their babies were also started on AZT within 24 hours of birth and continued on it for six weeks. The infants were followed for 18 months, and they will continue to be followed until the age of 21.
Yvonne J. Bryson, a pediatrician at UCLA, said it was not clear why some HIV-infected mothers transmit the virus to their babies while others do not.
She hypothesized that it could be a variety of factors, including the amount of virus in the mother’s bloodstream and the health of her immune system. Although studies are continuing, it appears that a sizable number of babies are infected during the birth itself, Bryson said.
She said the transmission rates varied widely among countries. European countries have the lowest rate, with about 13 percent of HIV-infected women giving birth to infected babies. The highest rate, she said, is in Kenya, where about half of infected pregnant women have babies who are infected.
Use of AZT as a therapy for pregnant women in such underdeveloped countries is problematic. The drug is expensive and would be hard to administer outside well-equipped medical facilities.
Most women in developing countries also breast-feed their babies. HIV can be transmitted through mother’s milk.
Nonetheless, Dr. Joep Lange, chief of AIDS research at the World Health Organization, said the agency wants to conduct a small-scale test of an anti-AIDS drug among HIV-infected pregnant women in several developing countries.
The U.S. government and France are also considering scaled-down tests of AZT among pregnant women with HIV in Africa and Thailand, said James Curran, head of AIDS programs at the Centers for Disease Control and Prevention.