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

Abstract

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.

Crimean-Congo hemorrhagic fever virus vaccine: past, present, and future

“…Furthermore, frequently vaccination with recombinant MVA vaccines generally leads to a progressive reduced ability of such Immunogenics, probably because of the vector- related humoral responses [77,78]. Unsuccessful outcomes of clinical trial I of a MVA-based HIV vaccine [79,80] have suggested that scientists need more researches to better understanding about the key mechanisms of antigen presentation [81,82], immune system [83], and vector-specific antibody responses [84], so that it can be possible to increase the immunogenicity of presently accessible MVA vaccines [75,85].…”