Study: Low levels of AZT could reduce number of HIV-positive babies

Finding would have key impact in developing world

February 18, 1998
Web posted at: 11:17 p.m. EST (0417 GMT)

ATLANTA (CNN) -- Low levels of the anti-HIV drug AZT may help prevent transmission of the virus from infected mothers to their babies, a finding with potentially important ramifications for the developing world.

The U.S. Centers for Disease Control and Prevention in Atlanta on Wednesday reported results of a study on 400 HIV-infected women in Thailand, which found that those taking low doses of AZT in the weeks before delivery were half as likely to give birth to an HIV-infected baby as those receiving a placebo.

Higher doses of AZT, given over a longer period of time, have become the standard of care for HIV-positive pregnant women in the United States and Europe, cutting transmission to newborns by nearly 70 percent.

Because of the cost and the logistical problems associated with such a long-term regimen, that treatment is considered impractical for the developing world.

However, CDC researchers say the results of the new study show that low-dose therapy, while not as effective as the treatment used in Europe and the United States, does offer improved odds for HIV-positive women in the developing world at one-tenth of the cost

"Now that this practical and feasible regimen has been proven safe and effective, these findings will help extend perinatal HIV prevention to many developing countries that previously had no realistic therapy options," said Dr. Helene Gayle of the CDC.

CDC defends use of placebo in study

In the Thai study, half of the pregnant HIV-positive women were given AZT and the other half a placebo. Among those who got AZT, 9 percent gave birth to babies infected with HIV. Among those getting the placebo, more than 18 percent had HIV-positive babies.

Some critics of the CDC study charged that it was unethical to give some women a placebo, despite the fact that experience in the industrial world strongly indicated that AZT could help prevent transmission of HIV to babies. But CDC officials defended the study design, saying using a placebo comparison group was the only way to prove that low-dose therapy was safe and effective.

"Without the placebo, the wrong conclusions about efficacy could have been easily drawn," Gayle said. "We would not be able to demonstrate to policy makers in Thailand and other countries that the therapy is safe."

However, with that thesis established by the Thai study, researchers say they will offer AZT to all of the women enrolled in a similar study now under way in Africa.

Senior Medical Correspondent Dan Rutz contributed to this report.

Extended Coverage:

• CNN In-Depth Health - HIV/AIDS

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Related sites:

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• American Association for the Advancement of Science
• Dr. David Ho: Turning the Tide Against AIDS
• National Institute of Allergy and Infectious Diseases
• Pasteur Institute
• Dr. David Ho: Turning the Tide Against AIDS
  • Office of AIDS Research - National Institutes of Health
• Red Ribbon Net
  • AIDS Daily Summary - short summations from the CDC that give news and highlights of news relating to HIV/AIDS and related diseases.

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