Factors Associated with Study Visit Compliance among Participants in a Simulated HIV Vaccine Efficacy Trial Open Access

Ebrahim-Zadeh, Shideh (Spring 2018)

Permanent URL: https://etd.library.emory.edu/concern/etds/9019s2507?locale=en
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Abstract

Background: Sub-Saharan Africa is home to over half of the total number of people living with HIV globally. Certain subpopulations such as female sex workers (FSW) and single mothers (SM) are disproportionately affected due to having multiple sex partners, poverty, higher chance of experiencing sexual violence, and lack of family/social support. This subpopulation can benefit from an HIV vaccine and should be included in efficacy trials. Vaccine trials are costly and time-intensive; therefore, having participants who adhere to the study protocol is crucial. We conducted a Simulated HIV Vaccine Efficacy Trial (SiVET) in Zambia in preparation for an HIV vaccine trial and evaluated factors associated with full visit compliance among participants.

Methods: SiVET enrolled 159 FSW/SM (recruited from an observational cohort) and randomized them to receive measles, mumps, rubella (MMR) and tetanus, diphtheria, pertussis, inactivated polio (Tdap-IPV) vaccines at month 0 or 3, and followed them for 12 months. Main-study group and the immunology sub-group had 11 and 15 visits, respectively. Participants received appointment reminders by phone or text (if available) and were visited at home if they missed a visit. Demographic, behavioral, and clinical data were used in logistic regression to model perfect clinic attendance within visit windows.

Results: Retention was 96.2%. 68 (42.8%) women attended all visits inside window, 58 (36.4%) attended all visits some outside window, and 33 (20.8%) missed at least 1 visit (median: 1). FSW/SM who had never been married (aOR = 2.17) and with more time in the cohort pre-SiVET (aOR = 1.73) were significantly more likely to have perfect attendance. Reasons for late/missed visits were unknown/unable to contact, traveling, and clinic closed for holidays. No significant differences were observed between the two risk groups, FSW and SM, or other factors including age, number of children, literacy/education, alcohol use, enrolled in sub-study, pregnancy, seroconversion, and adverse event.

Conclusions: Study retention was high. Having a preparatory cohort is conducive to enrolling the most compliant women. Providing participants with mobile phones may improve attendance. Screening should inquire about frequent travel. Visit calendars should be established in advance to ensure visit windows not fall over long holidays.

Table of Contents

INTRODUCTION ................................................................................ 1

HIV in Zambia, sub-Saharan Africa ..................................................................... 1

Current HIV Control Strategies ............................................................................ 2

The Need for an HIV Vaccine ............................................................................... 3

METHODS ......................................................................................... 6

Study Design ......................................................................................................... 6

Ethics ..................................................................................................................... 8

Eligibility Criteria ................................................................................................. 8

Data Collection ...................................................................................................... 9

Analysis ................................................................................................................. 9

RESULTS ......................................................................................... 12

Distribution of Visit Attendance ......................................................................... 12

Bivariate Analysis ............................................................................................... 13

FSW and SM combined (Table 5a) ................................................................. 13

FSW only and SM only (Tables 5b, 5c) ........................................................... 14

Logistic Regression ............................................................................................. 14

Model 1: FSW and SM combined (Table 6) .................................................... 14

Models 2 and 3: FSW only and SM only (Table 6) ......................................... 15

DISCUSSION ................................................................................... 16

Statement of Principal Findings ......................................................................... 16

Explanation of Findings and Relation to Other Studies .................................... 16

Weaknesses of Our Study ................................................................................... 18

Strengths of Our Study ....................................................................................... 19

Public Health Implications and Future Research .............................................. 19

Public health implications ............................................................................... 19

Future research................................................................................................ 20

REFERENCES .................................................................................. 21

TABLES ........................................................................................... 24

Table 1. Inclusion and exclusion criteria for SiVET study enrollment, Zambia, 2017 ..................................................................................................................... 24

Table 2. SiVET study participation timeline and activities, by study group, Zambia, 2017 ....................................................................................................... 25

Table 3. Data collected by risk group prior to SiVET study enrollment, Zambia, 2017 ..................................................................................................................... 26

Table 4. Distribution of visit attendance, SiVET study, Zambia, 2017 .............. 27

Table 5a. SiVET Study participant demographic characteristics stratified by risk group, Zambia, 2017 .................................................................................... 28

Table 5b. SiVET Study participant demographic characteristics stratified by risk group (FSW only), Zambia, 2017 ................................................................. 31

Table 5c. SiVET Study participant demographic characteristics stratified by risk group, Zambia, 2017 .................................................................................... 35

Table 6. Logistic regression results describing the association between attending all visits in window (versus not) and participant demographic characteristics, stratified by risk group, SiVET study, Zambia, 2017 ................ 39

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