Are Women Who Work in Bars, Guesthouses and Similar Facilities a Suitable Study Population for Vaginal Microbicide Trials in Africa?

BACKGROUND: A feasibility study was conducted to investigate whether an occupational at-risk cohort of women in Mwanza, Tanzania are a suitable study population for future phase III vaginal microbicide trials. METHODOLOGY/PRINCIPAL FINDINGS: 1573 women aged 16-54 y working in traditional and modern bars, restaurants, hotels, guesthouses or as local food-handlers were enrolled at community-based reproductive health clinics, provided specimens for HIV/STI and pregnancy testing, and asked to attend three-monthly clinical follow-up visits for 12-months. HIV positive and negative women were eligible to enter the feasibility study and to receive free reproductive health services at any time. HIV prevalence at baseline was 26.5% (417/1573). HIV incidence among 1156 sero-negative women attending at baseline was 2.9/100PYs. Among 1020 HIV sero-negative, non-pregnant women, HIV incidence was 2.0/100PYs, HSV-2 incidence 12.7/100PYs and pregnancy rate 17.8/100PYs. Retention at three-months was 76.3% (778/1020). Among 771 HIV sero-negative, non-pregnant women attending at three-months, subsequent follow-up at 6, 9 and 12-months was 83.7%, 79.6%, and 72.1% respectively. Older women, those who had not moved home or changed their place of work in the last year, and women working in traditional bars or as local food handlers had the highest re-attendance. CONCLUSIONS/SIGNIFICANCE: Women working in food outlets and recreational facilities in Tanzania and other parts of Africa may be a suitable study population for microbicide and other HIV prevention trials. Effective locally-appropriate strategies to address high pregnancy rates and early losses to follow-up are essential to minimise risk to clinical trials in these settings

Prevalence and incidence of pregnancy, HIV and STIs among eligible women attending at baseline (n = 1020).

<p><b>1.</b> Participants were tested for each incident endpoint at baseline, and at three-monthly intervals during follow-up. Incidence was calculated as the number of new cases divided by the total time in years that participants remained in the study without the incident endpoint of interest. Following standard practice, participants were considered censored at their last recorded study visit.</p><p><b>2.</b> Pregnancy and HIV seropositive status were initial study exclusion criteria. By definition, HIV prevalence was therefore zero among 1020 eligible women at baseline.</p><p><b>3.</b> Incident cases were defined as those who tested positive for both TPPA and RPR for the first time during follow-up and exclude women with active syphilis (TPPA+ and RPR+) at baseline.</p

Factors associated with re-attendance¹ among 771 eligible women attending at three months.

<p><b>1.</b> Attendance was defined on a four–level [0, 1, 2 and 3] ordinal scale as the number of visits made after a second visit at 3 mo (i.e. zero, one, two, or three additional visits) and modelled using ordinal logistic regression. The OR is the estimated odds ratio of ≥k visits vs </p><p><b>2.</b> Odds Ratio adjusted for age.</p><p><b>3.</b> Odds Ratio adjusted for age, clinic site, facility type, partners in past 3 months, travel, and permanence.</p><p><b>4.</b> Test for trend used to assess significance of term in ordinal logistic regression.</p><p><b>5.</b> Travel in the three months preceding the first clinic visit was categorised as: Low (zero nights away from home), Moderate (≥1 night but less than one continuous week away from home) and High (≥1 continuous week away from home on one or more occasions).</p><p><b>6.</b> Permanence of home and workplace location was categorised as: High (lived in the same house and worked at the same facility during the past year); Moderate (lived or worked at the same location for <1 year and moved house no more than once in the previous year); Low (lived or worked at the same location for <1 year and moved house twice or more in the previous year).</p

Selected socio-demographic characteristics of eligible sub-cohorts at baseline (n = 1020) and 3 mo. visit (n = 771).

<p><b>1</b> One participant with no recorded age;</p><p><b>2</b> Travel in the three months preceding baseline clinic visit was categorised as: Low (zero nights away from home), Moderate (≥1 night but less than one continuous week away from home) and High (≥1 continuous week away from home on one or more occasions);</p><p><b>3</b> Permanence of home and workplace location was categorised as: High (lived in the same house and worked at the same facility during the past year); Moderate (lived or worked at the same location for <1 year and moved house no more than once in the previous year); Low (lived or worked at the same location for <1 year and moved house twice or more in the previous year).</p

Prevalence of STIs, pregnancy, contraception and reported sexual behaviour at baseline and scheduled follow-up visits among 1020 potential trial participants.

<p><b>1.</b> For each variable, we modelled the change in prevalence between visits using a random-effects logistic regression model adjusting for visit as a continuous variable and including a random intercept. This modelling approach adjusted for the expected additional correlation between multiple responses by the same participant. We calculated formal tests of significance using likelihood ratio tests, and the p-values from these tests are presented in the final column of the table.</p><p><b>2.</b><i>T. vaginalis</i> sample N = 220. Measurements made at recruitment (visit 1) and at 12 months (visit 5).</p><p><b>3.</b> Pregnancy status was an initial study exclusion criterion. Prevalence at Visit 01 was therefore zero among eligible participants.</p

Re-attendance among women eligible to enrol in a future microbicide trial.

<p><b>1</b> At baseline, there were 1573 attendees. Of these 1156 (73.5%) were HIV negative, 1409 (89.6%) were not pregnant, and 1020 (64.8%) were both HIV negative and not-pregnant and therefore met broad eligibility criteria for enrolment into a future microbicide trial.</p><p><b>2</b> At the 3-month clinic visit, 778/1020 (76.3%) women originally considered eligible for enrolment re-attended; 7/778 women sero-converted between baseline and 3 mo. visits leaving a total of 771 ‘eligible’ women at 3-months.</p><p><b>3</b> Attendance  =  % of all possible follow-up visits that were actually attended.</p