CROI 2015 Program and Abstracts

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Poster Abstracts

Crude and Adjusted Odds Ratios for Perinatal HIV Transmission BAN Study, Lilongwe, Malawi 2004-2010

*Adjusted for all other variables in multivariable model **Anemia defined as hemoglobin<11 g/dL —Not included in multivariable model

Conclusions: Identifying factors associated with MTCT independent of viral is needed to further improve PMTCT programs. Maternal anemia, food insecurity, STI in the last 12 months, and past history of herpes zoster were significantly associated with perinatal MTCT independent of viral load in this cohort of previously untreated mothers. Maximizing maternal health will be particularly important to achieve elimination of perinatal MTCT worldwide. 869 High Rate of HIV Superinfection After Delivery: Secondary Analysis of the PEPI Trial Andrew D. Redd 1 ; SarahWendel 1 ; Andrew Longosz 1 ; Jessica M. Fogel 2 ; Newton Kumwenda 3 ; Sufia Dadabhai 3 ; Susan H. Eshleman 2 ; Stephen Porcella 4 ;Thomas C. Quinn 1 ;TahaTaha 3 1 National Institute of Allergy and Infectious Diseases, Baltimore, MD, US; 2 Johns Hopkins University School of Medicine, Baltimore, MD, US; 3 Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, US; 4 National Institute of Allergy and Infectious Diseases (NIAID), Hamilton, MT, US Background: HIV superinfection (SI) occurs when an infected individual acquires a distinctly new HIV strain, and can occur at rates comparable to primary HIV incidence. This study examined the risk of post-partum SI in HIV-infected women from the Post-Exposure Prophylaxis of Infants (PEPI) trial in Malawi, and evaluated if SI is associated with an increased risk of postnatal mother-to-child transmission (MTCT). PEPI demonstrated that infants who received 14 weeks of extended antiretroviral prophylaxis (ARV; nevirapine or nevirapine plus zidovudine) were at lower risk of acquiring HIV through breastfeeding than infants who received a short course of ARV prophylaxis. Methods: Samples fromwomen who transmitted HIV to their babies via breast milk (transmitters; infants were HIV- at six weeks of age, but positive later) were screened for HIV-SI (n=91). The 91 cases were matched as a group to women who did not transmit to their babies (non-transmitters) by study arm, follow-up time and sample availability. Samples from delivery and a follow-up visit for each woman were amplified and pyrosequenced in two genomic regions (p24 and gp41). HIV SI was established if the follow-up sample contained a new, phylogentically distinct viral population that was a greater genetic distance from the original viral strain than what would be expected based on viral evolution. HIV SI and MTCT risk were examined by logistic regression, and adjusted for study arm, viral load and CD4 count at delivery, time to resumption of sex, and breastfeeding duration. Results: PostpartumMTCT was associated with lower initial CD4 counts (p=0.001) and higher viral loads (p<0.0001) at delivery. There were eight SIs in the transmitter group (8/91) with a rate of SI of 7.5/100 person years (pys). This compares to six SIs in the non-transmitter group (6/91) for a rate of SI of 5.3/100pys (p=0.78). HIV SI was not associated with an increased risk of postnatal MTCT after adjusting for factors that influence transmission (adjusted odds ratio=2.73, 95% confidence interval=0.67-11.17; p=0.16). Conclusions: In this study, there was a relatively high rate of HIV SI in postnatal HIV-infected women. HIV SI did not increase the risk of postnatal MTCT in this study, which may be due to the limited sample size and the extended ARV prophylaxis in a portion of the infants. Further research in different populations will be needed to determine the relationship between HIV SI and transmission. 870 Decline in Early Mother-to-Child HIV Transmission (MTCT) Risk Over Time in Botswana Kathleen M. Powis 1 ; Gbolahan Ajibola 2 ; Jean Leidner 3 ; Kara Bennett 4 ; Florence Chilisa 2 ; Keabetwe Bedi 2 ; Chipo Petlo 7 ; Michael D. Hughes 8 ; Roger Shapiro 5 ; Shahin Lockman 6 1 Massachusetts General Hospital, Harvard Medical School, Boston, MA, US; 2 Botswana Harvard AIDS Institute, Gaborone, Botswana; 3 Goodtables Data Consulting, Norman, OK, US; 4 Bennett Statistical Consulting, Inc, Ballston Lake, NY, US; 5 Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, US; 6 Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, US; 7 Botswana Ministry of Health, Gaborone, Botswana; 8 Harvard School of Public Health, Center for Biostatistics in AIDS Research, Boston, MA, US Background: Botswana transitioned fromWHO “Option A” (AZT for HIV-infected pregnant women with CD4>250 cells/mm 3 ) to universal triple-antiretroviral (ARV) for all pregnant women (“Option B”) starting March 2011. This policy was implemented over time (and at all facilities by Jan 2013). Methods: We used data from an ongoing trial of cotrimoxazole prophylaxis for infants born to HIV-infected women, the Mpepu study, to analyze trends in PMTCT coverage and transmission. HIV-infected women were eligible for enrollment regardless of CD4, viral load or treatment during pregnancy. ARVs were provided by Botswana Government facilities, not by the study. Mpepu infant HIV DNA PCR testing occurred at birth and 2-4 weeks of life at study sites in Gaborone, Molepolole, and Lobatse. We compared ARV regimen and MTCT rates among mother-infants pairs enrolled May 2011-Dec 2012 vs. Jan 2013-Jun 2014. Results: 2,527 infants born to 2,494 HIV-infected women enrolled in the Mpepu study fromMay 2011 through Jun 2014, representing ~33% of HIV-infected women delivering; 85% of mothers chose to formula-feed. Overall, 1,704 (68%) mothers received 3 ARVs during pregnancy (Fig 1): 59% of the mothers prior to Jan 2013, and 78.5% from Jan 2013 on (p < 0.0001). Among women initiating 3 ARVs in pregnancy, the median duration at delivery was significantly longer for women delivering after Jan 2013 (16 weeks) vs. before Jan 2013 (12 weeks)(p < 0.0001). HIV DNA PCR was positive for 30 (1.2%) of the 2,527 infants by ~4 weeks of life. MTCT incidence was significantly lower for infants born after Jan 2013 (0.7%) vs. those born earlier (1.6%) (p = 0.04) and was only 0.6% among women treated with 3 ARVs during pregnancy. At delivery, 12 (75%) of the 16 transmitting women receiving 3 ARVs had detectable HIV RNA > 40 copies/ml (vs 27% of the 1688 non-transmitting women on 3 ARVs); only 5 (31%) of the 16 transmitting women on 3 ARVs started ≥

Poster Abstracts

524

CROI 2015