1. Virologic and immunologic response following antiretroviral therapy initiation among pregnant and postpartum women with acute HIV-1 infection: MOPDB0101 Alison L. Drake 1, John Kinuthia 7, Daniel Matemo 7, R. Scott McClelland 1,2,3, Barbra Richardson 4, Julie Overbaugh 6, Grace John-Stewart 1,2,3,5 Departments of Global Health 1, Medicine 2, Epidemiology 3, Biostatistics 4, and Pediatrics 5, University of Washington, Seattle, WA, USA; Fred Hutchinson Cancer Research Center, Human Biology, Seattle, WA 6 ; Department of Research and Programs, Kenyatta National Hospital, Nairobi, Kenya 7 No conflicts of interest to disclose Acknowledgements: Mama Salama Study participants and study staff, the Kenyan Ministry of Health, CDC/KEMRI, and the Ahero and Bondo District Hospitals Funding provided by NIH P01 HSD 064915 and CFAR P30 AI27757

2. Objective and population: Characterize virologic and immunologic responses among HIV-1 infected women with acute HIV-1 in pregnancy or postpartum initiating ART Study design and site: Prospective cohort study; Western Kenya Laboratory methods: Serial HIV-1 RNA nucleic acid amplification tests (NAATS); CD4 Statistical methods: Linear mixed effects models to measure changes in HIV-1 RNA Clinical and virologic characteristics post HIV-1 infection n n (%) or Median (IQR) Initiated ART At diagnosis 25 24 24 (96) 21 (88) HIV-1 RNA levels at ART initiation (log 10 copies/mL) 195.14 (4.22 – 5.68) Time to viral suppression (days)* 23166 (120, NA) CD4 count (cells/mm 3 ) At diagnosis 6 months post-diagnosis 6 month change 25 18 572 (450 – 764) 831 (488 – 1066) 170 (21 – 375) HIV-1 incidence 1.9% (25/1304); incidence rate 2.35 per 100 PY 12 (48%) infections detected during pregnancy *< 2.17 log 10 copies/mL (150 copies/mL)

3. HIV-1 RNA levels post-ART initiation HIV-1 RNA levels by pregnancy status* -0.2 -0.62 Monthly rate of change** * Among 18 women with ≥2 plasma samples ** Infected during pregnancy vs. infected postpartum; p=0.06 Lower limit of detection HIV-1 RNA levels ~0.4 log 10 higher in acute infection compared to other chronically infected cohorts ART acceptable, resulted in rapid viral decline Prompt ART in acute infection important for PMTCT Long-term follow-up needed to assess durability of viral suppression Conclusions