Pregnancy and contraceptive use among participants of childbearing potential in the HVTN 705 HIV vaccine trial in Southern Africa

BackgroundHIV vaccine trial participants include sexually active cisgender females who agree to avoid pregnancy during the active vaccination period. Nevertheless, some pregnancies occur in almost all studies. We examined contraceptive use, pregnancy incidence, and the relationship between pregnancy...

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Main Authors: Pamela Mda, Kathryn Mngadi, Bo Zhang, Randy Burnham, Michal Juraska, Ollivier Hyrien, Nigel Garrett, Thozama Dubula, Sinalo Toni, Sibi Joseph, Phillip Kotze, Susan Buchbinder, Azwidihwi Takalani, Frank Tomaka, Alexander Luedtke, Wouter Willems, Edith Swann, Julia Hutter, Huub Gelderblom, M. Juliana McElrath, Ludo Lavreys, Lynda Stranix-Chibanda, Alison C. Roxby, Linda-Gail Bekker, Glenda E. Gray
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-06-01
Series:Frontiers in Reproductive Health
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Online Access:https://www.frontiersin.org/articles/10.3389/frph.2025.1565933/full
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author Pamela Mda
Kathryn Mngadi
Bo Zhang
Randy Burnham
Michal Juraska
Ollivier Hyrien
Nigel Garrett
Nigel Garrett
Thozama Dubula
Sinalo Toni
Sibi Joseph
Phillip Kotze
Susan Buchbinder
Susan Buchbinder
Azwidihwi Takalani
Frank Tomaka
Alexander Luedtke
Wouter Willems
Edith Swann
Julia Hutter
Huub Gelderblom
M. Juliana McElrath
Ludo Lavreys
Lynda Stranix-Chibanda
Alison C. Roxby
Alison C. Roxby
Linda-Gail Bekker
Linda-Gail Bekker
Glenda E. Gray
author_facet Pamela Mda
Kathryn Mngadi
Bo Zhang
Randy Burnham
Michal Juraska
Ollivier Hyrien
Nigel Garrett
Nigel Garrett
Thozama Dubula
Sinalo Toni
Sibi Joseph
Phillip Kotze
Susan Buchbinder
Susan Buchbinder
Azwidihwi Takalani
Frank Tomaka
Alexander Luedtke
Wouter Willems
Edith Swann
Julia Hutter
Huub Gelderblom
M. Juliana McElrath
Ludo Lavreys
Lynda Stranix-Chibanda
Alison C. Roxby
Alison C. Roxby
Linda-Gail Bekker
Linda-Gail Bekker
Glenda E. Gray
author_sort Pamela Mda
collection DOAJ
description BackgroundHIV vaccine trial participants include sexually active cisgender females who agree to avoid pregnancy during the active vaccination period. Nevertheless, some pregnancies occur in almost all studies. We examined contraceptive use, pregnancy incidence, and the relationship between pregnancy and HIV seroconversion in one HIV vaccine trial.MethodsWe performed an exploratory analysis of data collected for HVTN 705/HPX2008, a phase IIb HIV vaccine trial enrolling cisgender women across 23 sites in five southern African countries. Baseline characteristics and contraceptive use were assessed among participants who became pregnant and those who did not during the active vaccination phase (months 0–15). Pregnancy incidence rates were calculated for this phase and the duration of follow up (36 months). Cox regression analysis was used to assess factors associated with incident pregnancy.ResultsThere were 2,636 participants who received at least one vaccine or placebo dose (mean age: 23 years, standard deviation: 3 years). At enrolment, when contraception was required, 62.9% reported using injectable contraceptives. Overall pregnancy rate was 2.95 per 100 person-years (95% CI: 2.40, 3.58), with 101 pregnancies reported by month 15. Cumulative incidence of pregnancy at month 15 was similar between trial arms (log-rank p = 0.688). Each additional year of age was associated with an 8% decrease in pregnancy incidence (p = 0.014). Women aged 31–35 years had the lowest pregnancy incidence [1.75 (0.48, 4.48) per 100 person-years]. In a Cox regression analysis covering months 0–15, all contraceptive methods significantly reduced the incidence of pregnancy compared to no contraceptive use. Oral contraception was associated with the least reduction in pregnancy risk; implants were associated with the most reduction in pregnancy risk (p < 0.001).ConclusionsIn HVTN 705/HPX2008, higher incidence of pregnancy was associated with younger age and oral contraception (compared to other methods). These data may inform future designs of HIV prevention or vaccine trials.
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spelling doaj-art-9a7c62c5ce0b4199961072c2aa614e392025-08-20T02:33:55ZengFrontiers Media S.A.Frontiers in Reproductive Health2673-31532025-06-01710.3389/frph.2025.15659331565933Pregnancy and contraceptive use among participants of childbearing potential in the HVTN 705 HIV vaccine trial in Southern AfricaPamela Mda0Kathryn Mngadi1Bo Zhang2Randy Burnham3Michal Juraska4Ollivier Hyrien5Nigel Garrett6Nigel Garrett7Thozama Dubula8Sinalo Toni9Sibi Joseph10Phillip Kotze11Susan Buchbinder12Susan Buchbinder13Azwidihwi Takalani14Frank Tomaka15Alexander Luedtke16Wouter Willems17Edith Swann18Julia Hutter19Huub Gelderblom20M. Juliana McElrath21Ludo Lavreys22Lynda Stranix-Chibanda23Alison C. Roxby24Alison C. Roxby25Linda-Gail Bekker26Linda-Gail Bekker27Glenda E. Gray28Nelson Mandela Academic Clinical Research Unit, Walter Sisulu University, Mthatha, South AfricaThe Aurum Institute, Johannesburg, South AfricaVaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, United StatesVaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, United StatesVaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, United StatesVaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, United StatesCentre for the AIDS Programme of Research in South Africa, University of KwaZulu–Natal, Durban, South AfricaDesmond Tutu HIV Centre, Cape Town, South AfricaNelson Mandela Academic Clinical Research Unit, Walter Sisulu University, Mthatha, South AfricaNelson Mandela Academic Clinical Research Unit, Walter Sisulu University, Mthatha, South AfricaNelson Mandela Academic Clinical Research Unit, Walter Sisulu University, Mthatha, South AfricaQhakaza Mbokodo Research Clinic, Ladysmith, South AfricaSan Francisco Department of Public Health, San Francisco, CA, United StatesDepartment of Medicine, University of California, San Francisco, San Francisco, CA, United StatesHutchinson Center Research Institute of South Africa, Chris Hani Baragwanath Academic Hospital, Soweto, South Africa0Janssen Research & Development, Titusville, NJ, United StatesVaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, United States1Janssen Research & Development, Beerse, Belgium2Division of AIDS, National Institute of Allergy and Infectious Diseases, Bethesda, MD, United States2Division of AIDS, National Institute of Allergy and Infectious Diseases, Bethesda, MD, United StatesVaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, United StatesVaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, United States1Janssen Research & Development, Beerse, Belgium3Clinical Trials Research Centre, University of Zimbabwe, Harare, ZimbabweVaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, United States4Departments of Medicine and Global Health, University of Washington, Seattle, WA, United StatesDesmond Tutu HIV Centre, Cape Town, South Africa5Department of Medicine, University of Cape Town, Cape Town, South Africa6South African Medical Research Council, Pretoria, South AfricaBackgroundHIV vaccine trial participants include sexually active cisgender females who agree to avoid pregnancy during the active vaccination period. Nevertheless, some pregnancies occur in almost all studies. We examined contraceptive use, pregnancy incidence, and the relationship between pregnancy and HIV seroconversion in one HIV vaccine trial.MethodsWe performed an exploratory analysis of data collected for HVTN 705/HPX2008, a phase IIb HIV vaccine trial enrolling cisgender women across 23 sites in five southern African countries. Baseline characteristics and contraceptive use were assessed among participants who became pregnant and those who did not during the active vaccination phase (months 0–15). Pregnancy incidence rates were calculated for this phase and the duration of follow up (36 months). Cox regression analysis was used to assess factors associated with incident pregnancy.ResultsThere were 2,636 participants who received at least one vaccine or placebo dose (mean age: 23 years, standard deviation: 3 years). At enrolment, when contraception was required, 62.9% reported using injectable contraceptives. Overall pregnancy rate was 2.95 per 100 person-years (95% CI: 2.40, 3.58), with 101 pregnancies reported by month 15. Cumulative incidence of pregnancy at month 15 was similar between trial arms (log-rank p = 0.688). Each additional year of age was associated with an 8% decrease in pregnancy incidence (p = 0.014). Women aged 31–35 years had the lowest pregnancy incidence [1.75 (0.48, 4.48) per 100 person-years]. In a Cox regression analysis covering months 0–15, all contraceptive methods significantly reduced the incidence of pregnancy compared to no contraceptive use. Oral contraception was associated with the least reduction in pregnancy risk; implants were associated with the most reduction in pregnancy risk (p < 0.001).ConclusionsIn HVTN 705/HPX2008, higher incidence of pregnancy was associated with younger age and oral contraception (compared to other methods). These data may inform future designs of HIV prevention or vaccine trials.https://www.frontiersin.org/articles/10.3389/frph.2025.1565933/fullHIV-1 vaccine trialsHIV preventionHIV incidencecontraceptionpregnancy
spellingShingle Pamela Mda
Kathryn Mngadi
Bo Zhang
Randy Burnham
Michal Juraska
Ollivier Hyrien
Nigel Garrett
Nigel Garrett
Thozama Dubula
Sinalo Toni
Sibi Joseph
Phillip Kotze
Susan Buchbinder
Susan Buchbinder
Azwidihwi Takalani
Frank Tomaka
Alexander Luedtke
Wouter Willems
Edith Swann
Julia Hutter
Huub Gelderblom
M. Juliana McElrath
Ludo Lavreys
Lynda Stranix-Chibanda
Alison C. Roxby
Alison C. Roxby
Linda-Gail Bekker
Linda-Gail Bekker
Glenda E. Gray
Pregnancy and contraceptive use among participants of childbearing potential in the HVTN 705 HIV vaccine trial in Southern Africa
Frontiers in Reproductive Health
HIV-1 vaccine trials
HIV prevention
HIV incidence
contraception
pregnancy
title Pregnancy and contraceptive use among participants of childbearing potential in the HVTN 705 HIV vaccine trial in Southern Africa
title_full Pregnancy and contraceptive use among participants of childbearing potential in the HVTN 705 HIV vaccine trial in Southern Africa
title_fullStr Pregnancy and contraceptive use among participants of childbearing potential in the HVTN 705 HIV vaccine trial in Southern Africa
title_full_unstemmed Pregnancy and contraceptive use among participants of childbearing potential in the HVTN 705 HIV vaccine trial in Southern Africa
title_short Pregnancy and contraceptive use among participants of childbearing potential in the HVTN 705 HIV vaccine trial in Southern Africa
title_sort pregnancy and contraceptive use among participants of childbearing potential in the hvtn 705 hiv vaccine trial in southern africa
topic HIV-1 vaccine trials
HIV prevention
HIV incidence
contraception
pregnancy
url https://www.frontiersin.org/articles/10.3389/frph.2025.1565933/full
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