Longer Prophylaxis Is More Effective in Reducing HIV in the Placenta and Is Associated
with Reduced HIV Transmission to Newborns
Use of zidovudine/
ZDV (Retrovir) from the 14th week until the end of pregnancy
has significantly reduced the rate of vertical transmission of HIV-1
in Europe and North America. A shorter duration of treatment has reduced this
rate in Africa and Southeast Asia to a lesser degree.
In
Southeast Asia, subtype E is the major subtype rather than subtype B, as in Western
countries. The objectives of this study were to determine the optimal duration
of ZDV prophylaxis for subtype E and to confirm its effectiveness at the histologic
level.
Fifty
pregnant women seropositive for HIV-1 subtype E were given ZDV prophylaxis consisting
of 300 mg administered twice daily, switching to 300 mg administered every 3 hours
from the onset of labor until delivery.
Twenty-seven
received "short-term" ZDV lasting 14 to 35 days before delivery, whereas
the other 23 received "long-term" ZDV lasting 62 to 92 days.
The
effectiveness of ZDV prophylaxis was assessed by detection of HIV-1 in the placenta
using in situ polymerase chain reaction (PCR).
All
babies in this study were tested up to one year of age. Three were not positive
until after one month of age, but one was positive as a neonate. Four neonates
were positive for HIV-1 as detected by PCR on peripheral blood, including one
in the neonatal period. All cases were from the short-term prophylaxis group.
Results
Decidual
glandular epithelial cells were the only cell type in the placenta that expressed
HIV proviral DNA under ZDV prophylaxis.
Sixty-seven
percent of placentas in the short-term ZDV group showed more than occasional positive
cells compared with 22% in the group receiving long-term ZDV prophylaxis (P <
0.02).
The
authors conclude, “This is first study to compare the effectiveness of short-term
and long-term ZDV prophylaxis with respect to the presence of HIV in the placenta.”
“Our
study shows that longer (at least 60 days) prophylaxis is more effective in reducing
HIV expression in the placenta and is associated with reduced transmission to
neonates.”
12/02/05
Reference
L
Bhoopat and others. Effectiveness of Short-Term and Long-Term Zidovudine Prophylaxis
on Detection of HIV-1 Subtype E in Human Placenta and Vertical Transmission. Journal of Acquired
Immunodeficiency Syndromes 40(5): 545-550. December 15, 2005.
