HIV-1 vertical transmission in Central West Brazil:
epidemiological, clinical and antiretroviral resistance profiles
K. Alcantara Correia, J. Lins Bacelar Acioli, M. Stefani Martins Araujo
Federal University of Goias, Immunology, Goiania, Brazil
Background: HIV-1 mother-to-child transmission (MTCT) is multifactorial, but high maternal viral load at delivery represents a major risk factor. Antiretroviral (ARV) prophylaxis has reduced MTCT, however drug resistance mutations may contribute to higher MTCT risk.
Objective: To investigate HIV-1 MTCT among mother-infant pairs from Central West Brazil.
Methods: Pregnant women were followed-up until delivery; newborns were monitored until the definition of HIV-1 diagnosis. Maternal viral loads, CD4+T cell counts and drug resistance profiles were assessed. HIV-1 exposed infants had viral loads and CD4+T cell counts determined at 30, 120 days; HIV-1 ELISA tests were performed at 1, 4, 12 months/until seroreversion. Protease/PR, partial Reverse Transcriptase/RT genes were PCR-amplified and sequenced from plasma RNA. PR/RT mutations were analyzed by the Stanford Database/International AIDS Society-USA list.
Results: Pairs of HIV-1-infected-mothers/exposed infants (n=126) were enrolled between June/2008-January/2010. Maternal median age was 26 years, 8.7% were (n=11) ≤19 years old. Heterosexual transmission predominated (87.3%); 46 women were diagnosed during pregnancy; 93.6% (n=118) had access to HAART; 85.3% (n=110) received intravenous AZT during labor; 50.8% (n=64) had cesarean section. Among AIDS mothers (n=39) the medians of CD4+T cell counts and viral loads were 376 cells/mm3 and 9,018 copies/ml respectively. Among assymptomatic mothers the medians of CD4+T cell counts and viral loads were 643 cells/mm3 and 7,719 copies/ml respectively. HIV-1 MTCT occurred in 2.38% (3/126) exposed infants: in one case, mother´s diagnosis was post-partum (viral load=2,840 copies/mL); the other 2 mothers received ARV prophylaxis and viral loads at delivery were below 1000 copies/mL (undetectable/ 1,862 copies/mL). The 3 pairs of HIV-1 transmitting mothers/infants had ARV susceptible viruses; 2/3 HIV-1 infected children were delivered vaginally.
Conclusion: In this cohort, HIV-1 MTCT occurred among mothers with low viral loads, ARV resistance was not associated with transmission and vaginal delivery probably represented the major risk for HIV-1 MTCT.
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