Joint Statement by the Centers for Disease Control and Prevention (CDC), the Joint United Nations Programme on HIV/AIDS (UNAIDS), The National Institutes of Health (NIH), and the Agence Nationale de Recherche Sur le SIDA (ANRS)

In 1994, a clinical trial demonstrated that by giving a regimen of AZT, known as the
ACTG 076 regimen, to non-,breastfeeding HIV-positive pregnant women, the risk of
perinatal transmission of HIV could be reduced by almost 70% (from 25% without AZT
to 8% with AZT). During this trial, AZT was administered orally to women five times a
day starting on average at 26 weeks gestation and continuing throughout pregnancy. It
was then given intravenously during labour, and orally four times a day to 'infants for six
weeks after they were born. In industrialized countries, such as France and the United
States, where this regimen has been implemented, significant declines in perinatal HIV
infection have been observed,
However, in most developing country settings, implementation of this prophylactic
regimen is precluded because of limited resources and health service facilities. The
CDC.,supported trial, undertaken in collaboration with the Ministry of Public Health in
Thailand, was therefore designed to determine whether an effective alternative could be
identified that did not require intravenous administration and which could be used "in
developing countries with an existing health infrastructure to support women who attend
prenatal clinics only very late in pregnancy, as is often the case in the developing world.The 'Thailand trial was part of -a globally coordinated research effort conducted by
several national and international sponsoring agencies in a number of developing
countries to also provide rapid and scientifically valid responses to a series of complex
questions related to -the safety and efficacy of AZT in specific contexts. These issues
needed to be addressed before the drug could be safely and effectively administered to
populations of women who are infected 'with different viral strains than those found in
the industrialized countries and havq different tolerance Ievqls and tranismission factors,
including breastfeeding.
The regimen evaluated in the Thailand trial was AZT started at 36 weeks gestation and
continued for the rest of pregnancy. The drug was administered orally to women twice
daily and during labour, and was not given to newborns.

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