Bridging the Gap: Conference Record [Abstract book, International Conference on AIDS (12th: 1998: Geneva, Switzerland)]

402 Abstracts 23302-23306

12th World AIDS Conference

variables of interest. However, at-term children born to symptomatic mothers (OR
= 14.4; p = 0.002) and those delivered vaginally (OR = 9.0; p = 0.04) had an
increased risk of becoming infected. In the latter group, prophylactic ZDV was
associated with a much lower risk of vertical transmission (OR = 0.03; p = 0.003).
Conclusions: Prophylactic ZDV and cesarean section seem to have a protective effect and decrease the risk of HIV-1 vertical transmission in children born at
term. These results suggest that in addition to prophylaxis with ZDV, either alone
or combined with other antiretroviral drugs, elective cesarean section should be
carefully considered especially for symptomatic women.
23302 1 Does a particular HIV-1 subtype strain favor vertical
transmission?
Martin Campodonico1, F. Fay2, D. Fay2, E. Perez Hernandez2, M. Taborda2.
1PTE. Roca 740, Rosario-2000; 2CTSP National University Rosario, Rosario,
Argentina
Background: It has been proposed that some HIV-1 subtypes are transmitted
more efficiently depending on the way of transmission. The objective of this study
was to provide some evidence of differences between the efficiency of HIV-1
vertical transmission of subtypes B and F (prevalent subtypes in our region),
determining the subtype prevalence in infected newborns, and comparing it with
the adult population prevalence seen in a previous study in our city.
Methods: We included in this study 32 HIV-1 infected children randomly
selected, born to infected mothers between 1990 and 1996. We obtained
blood/EDTA samples, and we determined the HIV-1 env-subtype starting from
the PBMC fraction using the Heteroduplex Mobility Assay (HMA). In only three
cases (9%) the mother-infant pair received the preventive protocol derived from
the ACTG 076. Most of the mothers (81%) breast-fed their children.
Results: By means of HMA, 21 samples were classified as belonging to subtype B strains, and 11 samples to subtype F, meaning a 65.6% prevalence of
subtype B and 34.4% of subtype F. There was no difference between both subtype
groups regarding the number of mother-infant pairs that received the ACTG 076,
or the ones who beast-fed. When we compared with the subtype prevalence in
adult population from a previous study; (76% 13, 22% F, n = 99) we found a
non significant difference (P = 0.35). Comparing with the subtype prevalence in
the women from that study (78% B, 22% F, n = 27), there was not a significant
difference either (P = 0.45).
Conclusions: There were no significant differences in the HIV-1 subtype prevalence between the newborn and adult population. Apparently, there might be no
differences between the efficiency of HIV-1 vertical transmission between subtype
B and F strains. However, because of the small number of newborns tested, the
possibility of minor efficiency differences between the vertical transmission of
subtypes B and F, cannot be ruled out.
23303 1 HIV-1 vertical transmission in the time of prophylactic
zidovudine
Emilia Sanchez-Ruiz1, C. Fortuny2, M. Lonca2, 0. Co112, R. Jimenez2. 'Health
Planning unit-Catalan Health Service Trav. De Les Corts, 131, 159 08028,
Barcelona; 2 Hospital Sant Joan De Deu Barcelona, Spain
Objective: To evaluate the effectiveness and feasibility of the use of zidovudine
(ZDV) for the prevention of HIV-1 vertical transmission in a university hospital in
Barcelona, Spain.
Design: Prospective study.
Methods: Children born to women with confirmed HIV-1 infection from January
1, 1987 to December 31, 1997 were included. Infants were divided into two
cohorts, A and B, according to year of birth; the cut-off date was October 1,
1994, when prophylactic use of zidovudine (ACTG 076) was implemented in our
hospital. Clinical and laboratory follow-up was scheduled at birth and every month
thereafter until the child was 18 months old.
Results: A total of 285 children were studied, 228 in cohort A and 57 in
cohort B. Mothers in cohort B tended to be older (mean age 27 yr vs 25 yr, p
< 0.0001), symptomatic (63.2% vs 10.1%) and have acquired their infections
through heterosexual contacts (35.1% vs 15.3%, p = 0.0007). The proportion of
cesarean sections did not differ between cohorts. In cohort B, all but 4 women
(93%) received prophylactic ZDV and so did their infants. Vertical transmission
rate dropped from 16.4% in cohort A to 4.3% in cohort B (p = 0.012). During the
follow-up of cohort B, 22 children were identified as born to mothers whose HIV-1
infection was not recognised during gestation or at delivery and, therefore, could
not benefit from either early diagnosis or preventive measures. Eleven children
became infected and three of them already died.
Conclusion: Prophylactic ZDV seems to be effective and feasible in preventing
HIV-1 vertical transmission in our setting. However, better outcomes could be
expected if the identification of infected women during gestation were exhaustive.
HIV-1 serostatus should be known for all childbearing women planning to become
pregnant or, at least, for all pregnant women in the first trimester of gestation.

S23304 Adequacy of prenatal care and perinatal zidovudine use
to prevent HIV transmission - Texas
Amy Lansky1, J.L. Jones1, S. Burkham2, K. Reynolds3, J. Bertolli1. 1CDC 1600
Clifton Rd. (MSE 47) Atlanta, GA 30333; 2Texas Dept. of Health, Austin, TX;
3Houston Dept. of Health, Houston, TX, USA
Background: In 1994 guidelines were published on the use of zidovudine (ZDV)

to prevent perinatal transmission of human immunodeficiency virus (HIV). The
ZDV regimen starts in the prenatal period.
Methods: We linked medical records of children born from January 1988 to
March 1996 with records of their HIV-infected mothers, identified by surveillance
projects conducted in 25 Texas hospitals. Categories for adequacy of prenatal
care (PNC) were determined by a combined index of month prenatal care began
(1-4 vs. 5-9) and proportion of recommended visits actually made (e.g., "intensive" = PNC began in month 1-4 and all recommended visits made). We examined
the association between PNC and ZDV prescription, using chi-square tests.
Results: We identified 338 mother-child pairs; 79 (23%) with incomplete PNC
information were excluded, resulting in 259 pairs for this preliminary analysis.
Overall, 21% received intensive prenatal care, 46% received inadequate prenatal
care and 9% received no prenatal care. Fifty-two (20%) births occurred after June
1994. The proportion that had intensive PNC increased over time (35% after June
1994 vs. 17% before, p = 0.01). The proportion prescribed ZDV was higher after
June 1994 than before (82% vs. 23% prenatally, 74% vs. 6% intrapartum, and
77% vs. 7% neonatally; p = 0.001 for all). Stratified by year of birth, pairs with
intensive PNC were more likely than others to be prescribed ZDV prenatally (adjusted odds ratio [aOR] 4.0; 95% confidence interval [Cl] 1.8-8.6) and intrapartum
(aOR, 3.3; 95% CI, 1.1-9.7).
Conclusions: Preliminary analyses indicate adequacy of prenatal care among
HIV-infected women increased over time. These data on early implementation
of the ZDV guidelines suggest that increasing adequacy of prenatal care increases likelihood of zidovudine prescription. Interventions are needed to help
HIV-infected pregnant women seek prenatal care early and often so therapy to
prevent HIV transmission can be initiated.
23305 1 Cesarean section (C/S) is effective in preventing perinatal
HIV-1 infection in newborns delivered within one hour of
ruptured membranes
Orlando Gomez-Martin, R.S. De Souza, C. Mitchell, M.J. O'Sullivan, G. Scott.
University of Miami 7727 SW 86 STreet A 1-202 Miami, FL 33143, USA
Objective: To assess the effect of zidovudine (ZDV), mode of delivery, and time
of ruptured membranes on HIV-1 perinatal transmission rates.
Methods: Medical records of 403 HIV-1 infected mothers and their infants born
between January 1, 1990 and December 31, 1994 were reviewed. A total of 319
mother-infant pairs were eligible for the study after excluding second born twins
(n = 3), second pregnancies (n = 27), infants with HIV-1 status indeterminate (n
= 51), and infected infants lost to follow-up prior to 24 months of age (n = 3).
Mother-infant pairs were divided according to ZDV regimen. No ZDV: (n = 152);
ZDV at some time during pregnancy, delivery, or postpartum (n = 167).
Definition: Rapidly progressive HIV-1 disease (RPD): occurrence of a CDC
class C clinical event or AIDS related death by 18 months of age. Time of ruptured
membranes was dichotomized as RM1: intact membranes or <59 min; RM2: >60
min. RPD's (n = 25) were excluded due to the possible association of RPD with
in utero infection.
Results: Transmission rates were 8.0% in RM1 and 13.2% in RM2. Analyses
were performed within each RM subgroup, according to ZDV Group and mode
of delivery. Transmission rates, multiple logistic regression Odds Ratios and their
95% CI are given in the following Table.
RM No ZDV No ZDV ZDV ZDV OR (95% CI)
Vaginal C/S Vaginal C/S No ZDV vs. ZDV V vs. C/S
<59 min 13.5%(5/37) 8.3%(1/12) 6.5%(3/46) 0.0%(0/18) 2.8(0.7,11.6) 3.0(0.4,23.7)
>60 min 15.7% (11/70) 31.8%(7/22) 5.8% (4/68) 9.5% (2/18) 3.4(1.3,9.1) 0.5(0.2,1.1)
Conclusions: Although the number of infected, Non RPD infants is small,
these results suggest that ZDV is effective in preventing perinatal transmission
regardless of time of rupture of membranes. Cesarean Section seems to be
effective only in newborns delivered within one hour of ruptured membranes.
However, since the practicability of this is limited, preserving the membranes
intact during labor is of upmost importance.
23306 Status of the perinatal HIV epidemic in the United States:
Success in perinatal prevention
Mary Lou Lindegren1, R.H. Byers1, P. Fleming1, P. Thomas2, P. Notley1,
M. Gwinn1, J. Ward1. 1 Centers for Disease Control, 1600 Clifton Road, Atlanta,
GA; 2New York City Department of Health, New York, NY, USA
Objective: To assess impact of prevention guidelines for maternal/neonatal ZDV
use (8/94) and voluntary, prenatal HIV testing (7/95), reasons for recent transmission, we analyzed trends in perinatally acquired (PA) HIV/AIDS.
Methods: To evaluate trends in recent birth cohorts, AIDS data reported by 9/97
were modeled with the Wang procedure which adjusts for incubation distribution
and reporting delays. Rates of PA AIDS and PCP diagnosed (dx) in children at
<1 yr per 100,000 births were calculated using national natality data. We used
the survey of childbearing women (SCBW) for rates/100 HIV+CBW. We analyzed

data from 29 states that monitor children with perinatal HIV exposure (exp) and
their subsequent infection (inf) and AIDS status.
Results: By 9/97, 7310 children with PA AIDS were reported. By yr of diagnosis,
PA AIDS incidence declined 43% from 1992 (901) to 1996 (516). By yr of birth,
from 1992 to 1995, rates per 100,000 births of PA AIDS and PCP in infants dx
at <1 yr of age declined 44%. PCP:AIDS rate ratio remained constant (see table
above).