Press Releases

2000 Releases

Shorter Treatment as Effective and Less Costly than Standard AZT Treatment in Reducing Mother-to-Child HIV Transmission

Boston, MA--A shorter course of AZT (zidovudine) therapy than currently prescribed for HIV-infected pregnant women may allow developing countries to afford treatment that could reduce babies’ chances of contracting HIV, according to a study in the October 5 New England Journal of Medicine.

The study, conducted by Harvard School of Public Health researchers and colleagues from Thailand and France, demonstrated that transmission of HIV from a mother to her child can be reduced with shorter treatments of the drug AZT at one-fifth the usual cost of $1,000. 

"These new strategies to reduce pediatric AIDS can be applied in developing countries with success rates equal to those treatments used in industrialized nations," explained Dr. Marc Lallemant, an HSPH research associate in the Department of Immunology and Infectious Disease and senior scientist at the Institut de Recherche pour le Développement, who directed the study.

"This is a large step forward in reducing pediatric AIDS," said Dr. Duane Alexander, Director of the U.S. National Institute of Child Health and Human Development, which helped fund the study in Thailand. "The less-expensive alternative could provide millions of women with treatment that could spare thousands of babies from being infected with the AIDS virus."

Of the more than 1,500 infants who get HIV from their infected mothers every day, 95 percent live in developing countries where the poverty level is high. Many mothers in these regions do not have access to the three to six-month AZT treatment, now considered the standard treatment to prevent perinatal HIV transmission in developed countries. This study, the largest of its kind to date, suggests an effective AZT treatment option for HIV-infected mothers that successfully reduces transmission to the child, at significantly lower cost.

In the Thailand study, scientists compared the effectiveness of four different treatment regimens: a simplified, standard AZT treatment starting at the 28th week of pregnancy and then given to the infant for six weeks (called long/long in this research); an AZT regimen that was shorter for the mother (starting at the 35th week of pregnancy, called short/long); a regimen shorter for the baby (three days’ AZT to the baby called long/short), or a regimen shorter for both mother and baby (short/short). During labor, AZT was given orally instead of by standard intravenous dosing.

Nearly 1,500 pregnant women from 27 different hospitals in Thailand participated in the randomized, double-blind study from 1997 to 1999. In 1998, at the urging of an independent committee that was monitoring the study, researchers dropped the short/short group because the HIV transmission rate was more than double that of the standard long/long AZT treatment group.

The study results showed that the long/short group had a transmission rate of 4.7 percent with an average treatment cost of $200. This transmission rate was similar to that observed in the long/long AZT group which was 6 percent. These two rates are not significantly different. 

Further analysis indicated the importance of mothers’ receiving the longer treatment: 5.1 percent of infants whose mothers received the shorter treatment were already infected with HIV at birth compared to only 1.8 percent of infants whose mothers got the longer treatment.

Scientists and physicians who were involved in this study include representatives of the Ministry of Public Health of Thailand; the Institut de Recherche pour le Développement (IRD) and the Institut National d’Etudes Démographiques, France; Chiang Mai and Mahidol Universities (Thailand) and Harvard University and the University of Massachusetts. This study was supported by the National Institute of Child Health and Human Development (NICHD) and the Fogarty International Center at the National Institutes of Health, USA; the Institut de Recherche pour le Développement, France; and the Department of Economic and Technical Cooperation, Thailand.

The abstract for the article may be found on NEJM's web site at:

For further information, please contact:

Robin Herman
Office of Communications
Harvard School of Public Health
677 Huntington Avenue
Boston, MA 02115
Phone: 617-432-4752

Robert Bock
National Institute of Child Health and Human Development
(301) 496-5133