aCenter for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA;

bChildren's Foundation Uganda, Baylor College of Medicine, Kampala, Kamutarpala, Uganda;

cFrontier Science and Technology Research Foundation, Buffalo, NY;

dCenter for Biostatistics in AIDS Research, Harvard University T.H. Chan School of Public Health, Boston, MA;

eFHI 360, Durham, NC;

fDivision of AIDS, Maternal Adolescent Pediatric Research Branch, Prevention Sciences Program, National Institute of Allergy and Infectious Diseases, Bethesda, MD;

gEunice Kennedy Shriver National Institute of Child Health and Human Development, Maternal and Pediatric Infectious Disease Branch, Bethesda, MD;

hUniversity of Zimbabwe-University of California San Francisco Collaborative Research Program (UZ-UCSF), Harare, Zimbabwe;

iPerinatal HIV Research Unit, University of the Witwatersrand Johannesburg, Chris Hani Baragwanath Hospital, Johannesburg, Gauteng, South Africa;

jMakerere University –John Hopkins University Research Collaboration (MUJHU CARE LTD), CRS, Kampala, Uganda;

kWits RHI, Maternal and Child Health, Johannesburg, Gauteng, South Africa;

lBotswana-Harvard AIDS Institute Partnership, Gaborone, Botswana;

mDivision of Infectious Disease, Brigham and Women's Hospital, Boston, MA;

nDivision of Global Women's Health, Department of Obstetrics and Gynecology, University of North Carolina-Chapel Hill, Chapel Hill, NC;

oHarvard University T.H. Chan School of Public Health, Department of Immunology and Infectious Diseases School of Public Health, Boston, MA; and

pUniversity of Washington, Department of Global Health, Medicine, Epidemiology and Pediatrics, Seattle, WA.

Correspondence to: Lisa M. Frenkel, MD, Center for Global Infectious Disease Research, Seattle Children's Research Institute, 307 Westlake Ave N Suite 500, Seattle, WA 98109-5219 (e-mail: [email protected]).

Funding of HIV drug resistance assays, analyses, and manuscript preparation was funded by R01AI147309 (Lisa M. Frenkel) and UM1AI106716 (International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) Laboratory Center). The overall support for the 2010 study was from the International Maternal Pediatric Adolescent AIDS Clinical Trials Network (IMPAACT) funded by the National Institute of Allergy and Infectious Diseases (NIAID) with co-funding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and the National Institute of Mental Health (NIMH), all components of the National Institutes of Health (NIH), under Award Numbers UM1AI068632 (IMPAACT Leadership and Operations Center) and UM1AI068616 (IMPAACT Statistical and Data Management Center) and by NICHD contract number HHSN275201800001I. The content is the sole responsibility of the authors and does not necessarily represent the official views of the NIH.

Presented at the conference on Retroviruses and Opportunistic Infection (CROI), February 22, 2023, Seattle, WA.

The authors have no conflicts of interest to disclose.

S.L., S.S.B., A.C., P.J-P., N.C., and L.C. designed the parental study. M.D.B., C.L.B., I.A.B., and L.M.F. designed the substudy. V.K., H.C., M.O., L.F., T.V., and S.M. implemented the parent study interventions and collected the clinical data and specimens. K.K., L.Z., and S.S.B. assisted in parent data acquisition for the substudy analysis. M.D.B. generated the HIV drug resistance data for the substudy. M.D.B., C.L.B., I.A.B., S.M.S., and L.M.F. accessed, verified, and analyzed the data. M.D.B. led the manuscript drafting and figure generation. All coauthors have reviewed and commented on the manuscript.

M.D.B. and V.K. have contributed equally.