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Session 136 Poster Abstracts
Pathogenesis and Co-Factors in MTCT
Wednesday, 1:30 - 3:30 pm
Hall B


796    
Is Maternal Syphilis Infection a Risk Factor for Mother-to-Child Transmission of HIV?
V Mwpasa1, J Kwiek2, S Rogerson3, M Molyneux4, D Kamwendo5, E Tadesse1, E Chalaluka1, P Wilson2, C Y Ou6, and Steven Meshnick*2
1Univ of Malawi Coll of Med, Blantyre, Malawi; 2Univ of North Carolina at Chapel Hill, USA; 3Univ of Melbourne, Parkville, Australia; 4Malawi-Liverpool-Wellcome Trust Clin Res Prgm, Coll of Med, Blantyre, Malawi; 5Univ of Michigan, Ann Arbor, USA; and 6CDC, Atlanta, GA, USA

Background:  HIV and syphilis co-infections are common. We investigated whether maternal syphilis infections in HIV-infected pregnant women are associated with increased risk of mother-to-child HIV transmission (MTCT).

Methods:  As part of a prospective cohort study investigating the effects of malaria on MTCT, pregnant women admitted at Queen Elizabeth Central Hospital in Malawi were tested for syphilis infection during the latent phase of labor by RPR and confirmed by TPHA. HIV-infected women and their newborn infants received single doses of nevirapine, according to standard protocols. Heel-prick blood samples were collected from infants born to HIV-infected women within 48 hours of birth, and at 6 and 12 weeks postpartum, for HIV-1 detection using HIV DNA PCR. Infants with positive HIV results at birth were classified as being infected in utero. Infants with negative results at birth but positive results at 6 or 12 weeks postpartum were classified as being infected intrapartum/postpartum.

Results:  Data were available for 504 mother-child pairs, with 46 mothers (9.1%) being syphilis-infected. In univariate analysis, the rate of in utero MTCT was higher in syphilis-infected (Sy+) (17.4% [8 of 46]) than in syphilis-uninfected (Sy–) mothers (7.4% [34 of 458]); odds ratio [OR], 95% confidence interval CI 2.63, 1.14 to 6.08. The rate of intrapartum/postpartum MTCT tended to be higher in Sy+ mothers (22.6% [7 to 31]) than in Sy– mothers (14.2% [48 of 331]), but the difference was not statistically significant (OR, 95% CI: 1.76, 0.72—4.32). In multivariate analysis, maternal syphilis remained significantly associated with in utero MTCT even after adjusting for maternal CD4 cell count, maternal fever, birth weight and maternal weight (adjusted OR, 95% CI 2.86, 1.22 to 6.74). In contrast, maternal syphilis was not associated with intrapartum/postpartum MTCT in multivariate analysis.

Conclusions:  These results suggest that maternal syphilis is a risk factor for MTCT in utero. Thus, screening and early treatment of maternal syphilis may reduce pediatric HIV infections, in addition to preventing abortions, stillbirths, and congenital syphilis.

Keywords: syphilis; mother-to-child transmission; malawi