HIV Test For At-Risk Pregnant Women To Help Reduce Infection to Newborns
who receive little or no prenatal care and who are at risk for contracting
the human immunodeficiency virus (HIV) that causes AIDS will soon be
offered a rapid HIV test aimed at reducing the rate of HIV transmission
to their newborns, in a study being conducted by Emory University and
Morehouse Schools of Medicine obstetricians at Grady Memorial Hospital
in Atlanta, Ga. The study began April 8.
The Maternal Infant Rapid
Intervention At Delivery (MIRIAD) study will evaluate innovative approaches
to counseling and voluntary rapid HIV testing for women in labor with
unknown HIV status. The primary objective is to assess the feasibility
of obtaining informed consent for HIV testing during labor or soon after
birth. MIRIAD, which is being funded by the Centers for Disease Control
and Prevention (CDC), also aims to discover barriers to HIV testing
and reasons for lack of prenatal care, and to evaluate neonatal adherence
and receipt of post-natal care for women identified as HIV-infected.
Other study sites include New York, Miami, New Orleans and Chicago.
"Women will be able to get
test results in a matter of hours, which will enable physicians to offer
treatment as soon as possible," said Michael K. Lindsay, M.D., co-principal
investigator, associate professor with the Emory University School of
Medicine, and director of the Maternal-Fetal Medicine Division. Steven
Nesheim, M.D., associate professor of infectious diseases, is principal
investigator. "This will help identify two specific populations -- new
mothers and their newborn children -- and offer the option of being
treated." Obstetricians at Grady deliver more than 4,000 babies each
year. Dr. Lindsay estimates that 20 percent, or 800, or those women
receive little or no prenatal care. Of the women who delivered at Grady
Hospital in 2001, 65 were HIV-infected. HIV is passed from one person
to another through blood-to-blood and sexual contact. A history of intravenous
drug abuse and having multiple sexual partners are the primary risk
factors. Infected women, in turn, can pass HIV to their babies during
pregnancy or delivery, or after delivery through breast-feeding. Without
taking preventive measures, the chances are about one in four that HIV
will pass from an HIV-positive mother to her baby before or during birth.
The MIRIAD study, using the
new, rapid test known as Determine, will draw the expectant mother's
blood and test for the presence of antibodies. All results from the
rapid test will then be confirmed with conventional antibody testing
known as the ELISA and the Western blot test. If the blood contains
antibodies, there will be an immediate reaction, indicating that the
mother-to-be is possibly infected. Results are available within a matter
of hours, compared to one to three days with the traditional ELISA and
Western blot HIV testing.
Lindsay said rapid testing
should help determine if Determine is just as effective as traditional
"That's the big debate: If
you do a rapid test on someone, is that as good as the traditional test?"
Lindsay says. "And that's one of the problems. Some of the tests are
not as good as the traditional tests, and that's going to be one of
the things we will actually be able to examine, because everyone who
has a positive rapid test, we'll do a traditional test on them, and
we'll go back and look and see what the correlation is."
Lindsay said women in the
study who test positive for HIV will receive anti-retroviral therapy
such as nevirapine, ZDV and 3TC intravenously or orally while they're
pregnant - and while they're in labor. Following delivery, their newborns
will receive the medication four times a day for the first six weeks
of life. This scenario of antiretroviral therapy reduces the HIV transmission
rate to the baby by approximately 70 percent from 25 percent to 8 percent.
If a woman does not take medication while she is pregnant but is identified
as being HIV-positive when she enters labor, she can be offered antiretroviral
therapy. In this scenario, the HIV transmission rate to the baby is
lowered by approximately 50 percent from 25 percent to 12 percent. Finally,
if antiretroviral medication is given only to the newborn because the
mother did not receive prenatal care and received no medication in labor,
the transmission rate to the infant is reduced approximately 50 percent.
"The best scenario is for
the mother to receive antiretroviral medication while she's pregnant,
in labor, and postdelivery. That's when she receives the maximum benefit,"
Lindsay said. "When a woman doesn't come in for prenatal care, she's
not going to receive antiretrovirals during pregnancy, but she can still
receive medication while she's in labor, and then administer medication
to her newborn. Although not as effective in reducing HIV transmission
as the full antiretroviral regimen, the partial regimen still reduces
At this time, three antiretroviral
drugs, ZDV, nevirapine, and ZDV/3TC, are recommended by the Public Health
Service for administration to HIV-infected pregnant women during labor
to prevent perinatal transmission of HIV. There has been great progress
made in the last decade in reducing the risk of perinatal HIV transmission.
HIV transmission rates as low as 1 percent to 2 percent have been achieved
in women receiving antiretroviral treatment who undergo elective cesarean
section prior to onset of labor or rupture of membranes, or in women
on antiretrovirals with a low viral load (<1,000 copies/ml) whether
they deliver vaginally or by elective cesarean.