Pregnancy rate disrupts Aids vaccine trials

• Women taking part in clinical studies conceiving in spite of abstinence pledges

Aids vaccine researchers are frustrated by the high pregnancy rates among women participating in clinical trials.

Now they want abstinence scrapped as a family planning method in future Aids vaccine clinical studies.

Writing of their frustrations in the current issue of the East African Medical Journal, a team of local researchers led by Prof Walter Jaoko of the University of Nairobi says that for them to succeed in their research, female participants in Aids vaccine trials must agree to use effective contraceptives.

The period within which they must stay pregnancy-free is specified as the effects of the vaccine on the unborn child are not known.

The Kenya Aids Vaccine Initiative (Kavi) researchers tell of one study where 39 participants were enrolled for trials.

The women received family planning counselling and were offered a choice of contraceptive methods at no cost. But four women conceived during the study.

“All four had opted for abstinence, but said they were coerced by their partners into unprotected sex,” says the study.

The researchers say that sexual abstinence should no longer be an option.

Explaining why abstinence has been an option, Kavi programme director Omu Anzala says at the early stages of the study, they select women with the lowest or zero risk of contracting HIV.

“At Phase I of the trials, we are testing mainly two things — the vaccine’s safety and whether it elicits any immune response and therefore need participants at very low risk of HIV infection,” Prof Anzala said in an interview on Tuesday.

Monitor the baby

If a participant conceives during the study period, vaccinations are stopped, compromising data from the trials.

“However, the woman is followed up and her pregnancy monitored. After the child is born, we monitor the baby for any possible ill effects,” Prof Anzala said.

“This development further erodes the already diminished contribution of female participation in Aids vaccine clinical trials. Every effort must therefore be made to ensure that participants in such trials do not get pregnant during the specified period and that they are retained to the trial’s conclusion,” says the study.