CROI 2019 Abstract eBook

Abstract eBook

Poster Abstracts

achieve elimination of mother-to-child HIV transmission (MTCT). Kenyan guidelines recommend retesting peripartum HIV negative women but data on implementation are lacking. We measured the frequency of HIV retesting during pregnancy, delivery, and postpartum and correlates of postpartum retesting. Methods: HIV-seronegative women seeking maternal and child health (MCH) services were enrolled in a cross-sectional study in rural Kenya at the Ahero County and Bondo sub-County Hospitals at one of the following time points: pregnancy; delivery; 6 weeks, 6 months, or 9 months postpartum. Data on programmatic retesting was abstracted fromMCH booklets to ascertain retesting during pregnancy and/or postpartum prior to the study visit. Retesting was defined as any HIV test after the initial antenatal care (ANC) test or after pregnancy if testing was not done in ANC. Poisson regression, clustered by site, was used to identify correlates of retesting among women enrolled at 9 months postpartum. Results: Among 1919 women enrolled, the median age was 23 years, 63% were married and the median number of times tested for HIV in the most recent pregnancy/postpartum period was 1 (interquartile range [IQR]: 1-2). Overall, 659 women were enrolled in the 3rd trimester, 128 within 48 hours after delivery, 387 at 6 weeks postpartum, 412 at 6 months postpartum, and 333 at 9 months postpartum. Prevalence of any programmatic HIV retesting was significantly higher at 6 weeks postpartum (46%) than in the 3rd trimester (23%), at delivery (5%), and at 6 months postpartum (28%) (p<0.001 for all). By 9 months postpartum, HIV retesting was associated with prior sexually transmitted infection (STI) diagnosis (Prevalence Ratio [PR]:1.28, 95% Confidence Interval [CI]:1.06-1.56; p<.001), higher gravidity (PR:1.05 per pregnancy, 95% CI:1.04- 1.06; p<.001), and being an orphan (PR:1.02, 95% CI:1.01-1.02 p=.02). Results were similar in a multivariable analysis of cofactors significant in the univariate model. Conclusion: Prevalence of retesting was higher in the early postpartum period and more common among women who had a history of STIs and higher gravidity. Strategies to offer retesting to all peripartumwomen in high prevalence regions could help identify incident maternal HIV and maximize prevention of MTCT efforts. 775 PRIMARY HIV PREVENTION IN PREGNANT AND LACTATING UGANDAN WOMEN: A RANDOMIZED TRIAL Jaco Homsy 1 , Rachel King 1 , Femke Bannink 2 , Zikulah Namukwaya 3 , Eric VIttinghoff 1 , Alexander Amone 3 , Francis Ojok 3 , Gordon Rukundo 3 , Sharon Amama 3 , Lawrence Ojom 3 , Pamela Atim 3 , Josaphat Byamugisha 4 , George Rutherford 1 , Elly T. Katabira 5 , Mary G. Fowler 6 1 University of California San Francisco, San Francisco, CA, USA, 2 Ghent University, Ghent, Belgium, 3 Makerere University–Johns Hopkins University Research Collaboration, Kampala, Uganda, 4 Makerere University, Kampala, Uganda, 5 Makerere University College of Health Sciences, Kampala, Uganda, 6 Johns Hopkins University School of Medicine, Baltimore, MD, USA Background: The ‘Primary HIV Prevention among Pregnant and Lactating Ugandan Women’ (PRIMAL) study aimed to assess the effectiveness of enhanced counseling for preventing HIV acquisition among HIV-uninfected pregnant women throughout the breastfeeding period. Methods: We conducted an unblinded randomized control trial between 02/2013 and 04/2016 to assess the effectiveness of enhanced counseling to prevent primary HIV infection among HIV-uninfected pregnant and lactating women in Uganda. HIV-uninfected pregnant women aged 15-49 were enrolled individually or in couples, randomized 1:1 to an intervention or control group, and followed up to 24 months postpartum or the end of breastfeeding, whichever came first. Both groups were tested for STIs and HIV at enrollment, delivery, 3 and 6 months postpartum and every 6 months thereafter until the end of follow-up. The intervention group received enhanced HIV prevention counseling every 3 months throughout follow-up. The control group received standard counseling at the time of HIV retesting. Results: We enrolled 820 HIV-uninfected pregnant women individually (n=410) or in couples (n=410 women and 410 partners) in one urban and one rural public Ugandan hospital. 675 (76%) women completed follow-up per protocol representing 1,439 women-years of follow-up. Although the frequency and proportion of condom use in the last 3 months or at last vaginal sex increased over follow-up, there were no statistically significant differences between the study arms. During follow-up, <2.1% of women tested positive for either syphilis, gonorrhea, C. trachomatis or T. vaginalis at any follow-up visit, while four women (two per arm) and no enrolled men became infected with

HIV, for an overall HIV incidence rate of 0.186 per 100 person-years. There were no statistically significant differences between study arms Conclusion: A sustained enhanced HIV prevention counseling intervention for up to 2 years postpartum among pregnant and breastfeeding women did not have a statistically significant effect on condom use or HIV incidence among these women. However, in both study arms, condom use increased over follow- up while STI and HIV incidence remained very low, suggesting that repeat HIV testing during breastfeeding, whether with standard or enhanced counseling, could be an effective strategy for the primary prevention of HIV among pregnant and lactating women in high HIV prevalence settings. Further research is needed to verify this hypothesis. 776 MODELING THE IMPACT OF PrEP FOR PREGNANT AND BREASTFEEDING WOMEN IN SOUTH AFRICA Dvora Joseph Davey 1 , Linda-Gail Bekker 2 , Yolanda Gomba 3 , Landon Myer 3 , Thomas J. Coates 1 , Leigh F. Johnson 3 1 University of California Los Angeles, Los Angeles, CA, USA, 2 Desmond Tutu HIV Foundation, Cape Town, South Africa, 3 University of Cape Town, Cape Town, South Africa Background: HIV-uninfected pregnant and breastfeeding women are at high risk of HIV acquisition, contributing to persistent high levels of MTCT. Pre- exposure prophylaxis (PrEP) is safe and effective in preventing HIV acquisition in pregnancy, but PrEP in pregnancy is not policy in many countries including South Africa (SA). We examined the potential impact of providing PrEP for SA pregnant and breastfeeding women. Methods: We used the Thembisa model, an established SA model to estimate the potential effect of introducing PrEP for pregnant and breastfeeding women. The model divides the SA population by key demographic factors and, among sexually active individuals, into high-risk (individuals with a propensity for concurrent partners and/or commercial sex) and low-risk individuals. We consider two scenarios for modelling PrEP uptake during pregnancy and breastfeeding: (1) a conservative scenario with model assumptions to match the experience reported in the Kenyan PrEP program for pregnant women (uptake probability=32% and 11% in high-risk and low-risk women, respectively); (2) an optimistic scenario with PrEP initiated by 80% of all pregnant women (high-risk and low-risk). PrEP in pregnant/breastfeeding women scenarios were compared with PrEP for female sex workers (FSWs), men who have sex with men (MSM), and adolescent girls and young women (AGYW). PrEP efficacy was assumed to be 65% throughout. Results: Between 2020-2030, providing PrEP to pregnant and breastfeeding women would reduce new HIV infections in SA by 2.5% (95%CI:2.4-2.6%) in the conservative scenario and 7.2% (95%CI:6.8-7.5%) in the optimistic scenario (Figure). This is similar to the FSW and MSM PrEP scenarios (1.9% and 3% respectively). Without PrEP, 76,000 (95% CI: 64,000-90,000) new cases of MTCT are expected over 2020-2030; PrEP provision may reduce these infections by 13% (95% CI: 13-14%) in the conservative scenario and 41% (95% CI: 39-44%) in the optimistic scenario. Under the optimistic scenario PrEP would have a proportionally greater impact on breastfeeding transmission (47% reduction, 95% CI: 44-49%) vs. in utero and intrapartum transmission (23% reduction, 95% CI: 18-27%). Conclusion: High levels of uptake of and adherence to PrEP among pregnant and breastfeeding women could fundamentally alter MTCT in SA. There is an urgent need for implementation research to identify interventions that will facilitate PrEP use during pregnancy and breastfeeding in this setting.

Poster Abstracts

CROI 2019 300