Pregnancy rates among female participants in phase I and phase IIA AIDS vaccine clinical trials in Kenya

East Afr Med J. 2009 Sep;86(9):430-4. doi: 10.4314/eamj.v86i9.54165.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AIDS Vaccines
  • Clinical Trials, Phase I as Topic
  • Clinical Trials, Phase II as Topic
  • Contraception Behavior
  • Female
  • Humans
  • Kenya
  • Pregnancy
  • Pregnancy Rate*
  • Research Subjects*
  • Retrospective Studies


  • AIDS Vaccines