1. Illness during pregnancy is associated with in utero human immunodeficiency virus type-1 transmission Carey Farquhar, MD, MPH University of Washington/University of Nairobi Collaborative Research Group

2. In utero HIV-1 transmission 20-30% of all infant HIV-1 infections among breastfeeding women –~200,000 infants acquire HIV-1 in utero each year Effective PMTCT interventions impact intrapartum/postpartum transmission –ARVs in 3 rd trimester –Nevirapine at delivery –Avoidance of breastfeeding –Early weaning from breastmilk Proportion of infant HIV-1 acquired in utero likely to increase

3. Research challenges Blood sample required at birth –Women deliver at home –Labor and delivery specimens difficult to obtain Misclassification –HIV-1 DNA not 100% sensitive –Late in utero indistinguishable from intrapartum or early breastmilk Women typically present in 3 rd trimester –Difficult to assess acute HIV-1 –Longitudinal co-factors not captured prospectively Kenyatta National Hospital, Nairobi

4. Factors that may influence in utero transmission Viral burden: –Cell-free/cell-associated HIV-1 –Acute HIV, advanced disease Antiretroviral therapy Infant gender: Female > Male Low birthweight Ascending infections –Chorioamnionitis, endometritis Dickover 1996; Mofenson 1999; Zijeneh 2004; Renjifo 2004; Thorne 2004; Magder 2005; Taha 2006; Biggar 2006

5. Specific Aim: To determine correlates of in utero HIV-1 transmission Study design and enrollment: Prospective cohort study HIV testing and recruitment at Nairobi City Council Clinics, 1999-2002 Enrollment before 32 weeks gestation Interview and exam at 32 weeks of pregnancy –Medical history, including illness during pregnancy –Sexually transmitted infections (syphilis, gonorrhea, chlamydia, trichomonas) –Bacterial vaginosis (BV) –CD4 count, HIV-1 RNA in plasma & cervical secretions STIs treated at subsequent study visit BV and HIV-1 RNA performed on batched specimens after study completed

6. Mother-infant follow-up: Specimens collected at delivery : –Maternal plasma & cervical secretions for HIV-1 RNA PCR –Infant blood for HIV-1 DNA (filter paper) and RNA PCR (plasma) ≤ 48 hours after birth In utero transmission defined as: –Positive HIV-1 DNA or RNA assay ≤ 48 hours after birth –Those without plasma for HIV-1 RNA at birth with positive assay at 1 month were excluded due to low sensitivity of filter paper DNA assays Infant HIV-1 status assessed every 3 months –Filter paper specimens for HIV-1 DNA with HIV-1 RNA PCR to confirm timing Every 2 weeks l* Every week l Hospital delivery l Monthly to 12 months Visits: *at 34-36 weeks zidovudine started

7. Results: Cohort description

8. Infant HIV-1 infection status

9. Maternal and infant characteristics In-utero transmissions (N=29) All others (N=422) Mean (SD) or number (%) Age (years) 25 (3.9)25 (4.4) Plasma HIV-1 RNA (log 10 copies/ml) * 5.0 (0.5)4.6 (0.9) Cervical HIV-1 RNA (log 10 copies/ml) * 3.0 (1.2)2.4 (1.0) CD4 count 486 (237)477 (243) CD4 percent * 19.8 (7.2)23.6 (8.9) Received ≥ 3 weeks AZT * 12 (43%)280 (66%) Infant female 19 (66%)198 (47%) Infant birthweight (kg) * 2.9 (0.5)3.1 (0.5) Infant maturity (weeks) * 38.5 (1.8)39.3 (1.8) *p-value ≤ 0.02

10. Maternal and infant characteristics 1 Includes fever > 1 month, diarrhea > 1 month, cough > 1 month, weight loss > 5 kg, dermatitis, and thrush In-utero transmissions (N=29) All others (N=422) Mean (SD) or number (%) STI (GC, CT, TV) 9 (32%)88 (21%) Bacterial vaginosis * 16 (59%)139 (35%) Hx of AIDS-related illness during past year 1 * 12 (41%)89 (21%) Hx of cough, fever or diarrhea during pregnancy * 15 (52%)120 (28%) *p-value ≤ 0.02

11. Correlates of IU transmission OR multivariate model (95% CI) 1 p-value Maternal plasma HIV-1 RNA (log10 copies/ml) 1.9 (1.1 – 3.1)0.02 Maternal cervical HIV-1 RNA (log10 copies/ml) 1.5 (1.0 – 2.3) 2 0.05 Maternal CD4 percent at 32 wks 1.0 (0.9 – 1.0)0.52 Received ≥ 3 weeks AZT 0.4 (0.2 – 1.0)0.04 Infant female 2.0 (0.9 – 4.5)0.11 Infant maturity (wks) 1.0 (0.8 – 1.2)0.73 Infant birthweight (kg) 0.6 (0.3 – 1.1)0.10 History of AIDS-related illness during past year 1 1.8 (0.8 – 4.3)0.18 History of cough, fever, or diarrhea during pregnancy 2.6 (1.2 – 5.8)0.02 Bacterial vaginosis at 32 weeks 3.0 (1.2 – 7.0)0.01 1 Adjusted for maternal viral load, maternal CD4% at 32 weeks, and whether received >3 weeks AZT 2 Adjusted for maternal CD4% at 32 weeks and whether received >3 weeks AZT prophylaxis

12. Summary and conclusions Transmission rate in utero was 6.3% Among HIV-1-infected infants, 33% infected in utero Factors associated with in utero transmission include: –Plasma and cervical HIV-1 RNA –<3 weeks of antenatal zidovudine –IIlness during pregnancy –Bacterial vaginosis What is the mechanism? –Illness: Transient ↑ viral load; immune activation; acute HIV-1 –BV: Upper genital tract disease 2° BV in lower genital tract

13. Future directions Maternal illness antenatally and BV not described and may be amenable to interventions Increased HIV-1 RNA testing at birth necessary for evaluation of in utero transmission Control of HIV-1 viral load and maternal health are important –Bacterial infections –Diarrheal diseases –Malaria –Role of prophylaxis –Malnutrition –Acute HIV-1 infection

14. Acknowledgments University of Nairobi Dorothy Mbori-Ngacha Rose Bosire Ruth Nduati Elizabeth Obimbo Phelgona Otieno Dalton Wamalwa Christine Gichuhi CTL study staff Fred Hutch Cancer Research Center Julie Overbaugh Sandy Emery Dana Panteleeff Mary Redman University of Washington Grace John-Stewart Barbara Lohman-Payne Barbra Richardson Jennifer Harris Mt. Kenya Mt. Rainier Support from NIH: NICHD and Fogarty International Center Mt. Kenya Thank you to all participants