Antiretroviral
Therapy at Conception Reduces Risk of Mother-to-child HIV Transmission
By
Liz Highleyman
It
is well-established that antiretroviral therapy can dramatically
reduce the likelihood of vertical HIV transmission. There is less
extensive information, however, about the effects of different
drugs or the influence of treatment timing and duration.
A team of researchers from the U.S., Belgium, and South Africa
analyzed outcomes among 1142 HIV positive pregnant women with
advanced immune suppression (< 250 cells/mm3 or other indications
for ART) who were treated between January 2004 and August 2008
at 2 clinics in Johannesburg that provided integrated prenatal
care and antiretroviral treatment.
The women had an average age of 30 years and a low median baseline
CD4 cell count of 161 cells/mm3. At the time of the study, South
African treatment guidelines called for ART initiation at 200
cells/mm3. (In late 2009, both South African guidelines and World
Health Organization global ART guidelines were revised to
recommend treatment below 350 cells/mm3). Some women had previously
received single-dose nevirapine
(Viramune) to prevent mother-to-child HIV transmission.
Results
 |
968
women (85%) started ART during pregnancy and had a mean treatment
duration of 10.7 weeks at the time of delivery. |
|
147
women (15%) became pregnant when they were already on ART
and had a mean treatment duration of 93.4 weeks at delivery.
|
|
The
overall rate of mother-to-child transmission was 4.9% (43
out of 874 babies with available data), as determined by a
positive infant HIV DNA PCR test 4-6 weeks after birth. |
|
No
differences in the rate of vertical transmission were detected
between women who took various combination ART regimens. |
|
The
transmission rate was 8-fold lower among women who became
pregnant while on ART compared with those who started treatment
during pregnancy (0.7% vs 5.7%, respectively; P = 0.01). |
|
Among
women who started ART during pregnancy, shorter treatment
duration was associated with lower likelihood of achieving
undetectable viral load. |
|
Each additional week of treatment during pregnancy reduced
the odds of vertical transmission by 8% (P = 0.02). |
|
Women
who received combination ART for 12 weeks or less had a vertical
transmission rate of 7.4%, the same as women treated with
single-dose nevirapine. |
"Late
initiation of HAART is associated with increased risk of mother-to-child
transmission," the researchers concluded.
They noted that women who started ART during pregnancy had an
unexpectedly high rate of vertical transmission relative to rates
observed in other resource-limited countries (5.7% vs the 2.3%
seen in a recent West African study, for example). Nevertheless,
the transmission rate was still about 3 times lower that the 17.4%
rate for women in the same area who received no antiretroviral
drugs during pregnancy.
The authors recommended that "Strategies are needed to facilitate
earlier identification of HIV-infected women," thereby enabling
them to start treatment sooner.
David Geffen School of Medicine at UCLA, Division of Infectious
Diseases and Center for Clinical AIDS Research and Education,
Los Angeles, CA; Reproductive Health and HIV Research Unit, University
of the Witwatersrand, Johannesburg, South Africa; Rahima Moosa
Mother and Child Hospital, Enhancing Children's HIV Outcomes (ECHO),
University of the Witwatersrand, Johannesburg, South Africa; Department
of Obstetrics and Gynecology, University of Gent, Gent, Belgium.
5/11/10
References
RM
Hoffman, V Black, K Technau, and others. Effects of Highly Active
Antiretroviral Therapy Duration and Regimen on Risk for Mother-to-Child
Transmission of HIV in Johannesburg, South Africa. Journal
of Acquired Immune Deficiency Syndromes 54(1): 35-41 (Abstract).
May 2010.
