Issues in Women's Participation in a Phase III Community HIV Vaccine Trial in Thailand

Abstract

To assess qualities and outcomes of women participating in a large, community-based HIV vaccine trial, the present study was conducted among female participants of the RV 144 prime-boost trial in Thailand from 2003 to 2009. Qualities of participation refer to complete vaccination, retention, and status change. Outcomes of participation refer to incident rate, adverse event, and participation impact event. A total of 6,334 (38.6%) women participated in the trial, of whom about 50% were classified as low risk and 11% as high risk. About 85% of participants completed four vaccinations and 76% were included in the per-protocol analysis of the on-time vaccination schedule. More women (88%) completed 42 months follow-up compared with men (85%). Women aged 21 and above had more adverse events compared to younger age groups. More women (5%) compared with men (3%) reported participation impact events (PIEs). High-risk women had more PIEs and a higher infection rate compared to the low-risk group. Complete vaccination and retention on last follow-up were more common in married women aged above 21, and being a housewife. Female volunteers showed the same qualities and outcomes of participation as males in the HIV vaccine trial. There was no statistically significant difference in vaccine efficacy between men and women, especially among the high-risk and married women. The study highlighted the important behavioral, social, and cultural issues that could be considered for future HIV vaccine trial designs.

A retrospective analysis of incident pregnancy in Phase 1 and 2a HIV-1 vaccine study participants does not support concern for adverse pregnancy or birth outcomes

“…Our analysis revealed that 18% of conceptions among vaccine recipients occurred during the main study phase, though the overall pregnancy rate during study conduct was low (3.09 per 100 w-yr). A similar finding was described in the groundbreaking RV 144 trial in Thailand 18 where 1922 incident pregnancies were recorded in 6334 women (30%) in equal proportions among vaccine and placebo recipients, 362 of those (18%) occurring within the first 6 months of participation 19 . Not surprisingly, younger women aged 25 years and below contributed over 70% of the pregnancies.…”

Incidence of unintended pregnancy among female sex workers in low-income and middle-income countries: a systematic review and meta-analysis

“…Most RCTs in this review required women to remain non-pregnant for continuation. 36 40 42 44–48 The majority of studies (n=19) took place in sub-Saharan Africa, most frequently in Kenya (n=8; table 1 ). There were also studies from the Americas (Mexico and the Caribbean) and East Asia (China, Thailand and Cambodia).…”

“…There were also studies from the Americas (Mexico and the Caribbean) and East Asia (China, Thailand and Cambodia). All except three 36 44 49 took place in urban settings. The study areas were frequently informal housing settlements, low-income areas or environments known for sex work and/or drug use.…”

“…Sex work was mainly defined as exchange of sex for money or goods (n=12) or money alone (n=4). In five studies, sex workers were self-identified, in two studies they were members of communities or working in areas known for commercial sex work 36 46 and in two studies no definition was provided. 48 50 Eighteen studies involved FSWs exclusively; the remainder targeted women with high-risk sexual practices or at high risk of HIV.…”

“… 48 50 Eighteen studies involved FSWs exclusively; the remainder targeted women with high-risk sexual practices or at high risk of HIV. These studies either reported pregnancy incidence in the sex work subgroup 36 42 44 51 or FSWs constituted more than two-thirds of the sample. 32 40 49 52 Fourteen studies were restricted to women without HIV at baseline, and one study to women living with HIV.…”