Pregnancy rates among female participants in phase 1 and phase 2A AIDS vaccine clinical trials in Kenya

  • WG Jaoko
  • H Ogutu
  • S Wakasiaka
  • R Malogo
  • R Ndambuki
  • J Nyange
  • G Omosa-Manyonyi
  • P Fast
  • C Schmidt
  • C Verlinde
  • C Smith
  • KM Bhatt
  • J Ndinya-Achola
  • O Anzala


Background: Female participants in AIDS candidate vaccine clinical trials must agree to use effective contraception to be enrolled into the studies, and for a specified period after vaccination, since the candidate vaccines’ effects on the embryo or foetus are unknown.
Objectives: To review data on female participants’ pregnancy rates from phase I and IIA AIDS vaccine clinical trials conducted at the Kenya AIDS Vaccine Initiative (KAVI) and to discuss the challenges of contraception among female participants.
Design: Descriptive observational retrospective study.
Setting: KAVI clinical trial site, Kenyatta National Hospital and University of Nairobi, Kenya.
Subjects: Thirty nine female participants were enrolled into these trials. They received family planning counselling and were offered a choice of different contraceptive methods, as per the protocols. All contraception methods chosen by the participants were offered at the study site at no cost to the participant.
Results: Four women conceived during the study period when pregnancies were to be avoided. All four had opted for sexual abstinence as a contraceptive method, but reported having been coerced by their partners to have unprotected sexual intercourse.
Conclusion: Abstinence is clearly not a reliable contraceptive option for women in developing-country settings. Effective female-controlled contraceptives, administered at the clinical trial site, may empower female participants to better control their fertility, leading to more complete clinical trial data.

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eISSN: 0012-835X