Willingness to participate in future HIV vaccine trials among men who have sex with men and female sex workers living in Nairobi, Kenya

High STI burden among a cohort of adolescents aged 12-19 years in a youth-friendly clinic in South Africa

Adolescents face a higher risk for HIV, STIs, and unintended pregnancy than any other age group in sub-Saharan Africa, and have unique health care needs as they navigate this period of growth and developmental milestones. We conducted the Youth Friendly Services study among adolescents in Rustenburg, South Africa to address some of these concerns. Participants aged 12-19 were followed quarterly for 12 months, asked at baseline about demographics, their sexual behavior, and tested for HIV, STIs, and pregnancy (girls). Report of sexual activity was not a requirement for enrollment. Assent and parental consent were obtained for participants under 18. Some follow up visits fell during COVID-mandated shutdowns, and we worked with participants to reschedule and extend follow up as appropriate. Here we present data on reported behaviors, participant attrition, risk of HIV, other STI, and pregnancy. From May 2018 to August 2019, we enrolled 223 HIV-negative, non-pregnant adolescents (64% girls). The median age was 17 (IQR: 14-18). Among the 119 (53%) participants who reported being sexually active at baseline, the median age at first sex was 16 years (IQR: 15-17). During follow-up, an additional 16 (7%) participants reported having their first sexual encounter. Among the sexually active participants, the incidence of HIV was 1.5 cases / 100 person-years at risk (PYAR, 95% CI: 0.4-6.0), the incidence of chlamydia was 15.7 cases (95% CI: 10.1-24.4), gonorrhea was 4.7 cases (95% CI: 2.1-10.5), and HSV was 6.3 cases (95% CI: 3.1-12.6); we observed no cases of incident syphilis. The incidence of pregnancy among sexually active girls was 15.0 pregnancies / 100 PYAR (95% CI: 8.5-26.5). Despite small numbers, the incidence of most STIs was significantly higher in females compared to males. We also observed two pregnancies and 5 incident STIs among participants who reported never having had sex, these tended to be younger participants. From March to September 2020, the clinic was shut down for COVID-19, and 53 study visits were postponed. Follow up was concluded in November 2020, a total of 19 participants were lost to follow up, however only one participant dropped off-study during COVID-19 shutdowns. Retention at the final visit was 91.5%. We successfully completed a prospective study of adolescents to learn more about the risks they face as they navigate sexual debut in the context of a program of youth-friendly counseling and services. Among self-reported sexually active participants, we observed a high rate of HIV, STI and pregnancy, however we also observed pregnancy and STIs among those who reported no sexual activity.

Sexually transmitted infection knowledge among men who have sex with men in Nairobi, Kenya

BACKGROUND

High rates of sexually transmitted infections (STIs) among men who have sex with men (MSM) have been reported, but there is little research on their STI knowledge. Our study sought to determine participants' characteristics that contribute to either high or low STI knowledge among MSM in Nairobi, Kenya.

METHODS

We mobilized MSM aged ≥18 years from Nairobi into a cross-sectional study. To determine their understanding of STIs, a pre-tested structured questionnaire was administered. Knowledge score was generated by summing up the number of responses answered correctly by a participant. We dichotomized scores as "low" and "high", by splitting the group at <12 and ≥12 which was the mean.

RESULTS

A total of 404 participants were interviewed between March and August 2020. The mean age was 25.2 (SD = 6.4) years. Majority were single (80.4%) and Christians (84.2%). All participants had some formal education ranging from primary to tertiary; the majority (92.3%) had secondary education or more. Most (64.0%) were employed and their monthly income ranged from <50->150 USD. Almost all (98.5%) were Kenyans. Of the 404 (90.6%) self-identified as male and (47.5%) reported to be exclusively top partners. Many (39.9%) reported being versatile, while those reporting to be bottom partners were, (12.6%). The last 12 months, (55.4%) of the participants reported having sex with men only and (88.6%) reported to have had multiple sexual partners. Participants scored an average of 12.2, SD 4.5. Multivariable backward elimination logistic regression revealed that participants who had tertiary education (aOR = 0.50, 95% CI 0.32-0.77), a higher income (aOR = 0.40, 95% CI 0.22-0.75) and were engaging in vaginal sex (aOR = 1.86, 95% CI 1.25-2.78) predicted significantly higher odds of high knowledge in the final multivariable model.

CONCLUSION

Participant's knowledge level regarding STIs was low. We recommend health care workers to continue educating patients about STIs.

Hepatitis B status and associated factors among participants screened for simulated HIV vaccine efficacy trials in Kenya and Uganda

INTRODUCTION

Hepatitis B (HBV) prevalence remains high in Sub Saharan Africa and among some key populations such as those with continued exposure through sexual contact. We assessed the HBV status among potential participants who were screened for simulated HIV vaccine efficacy trials in Kenya and Uganda.

METHODS

We conducted a cross sectional analysis of data collected from individuals who were screened in Kenya (Nairobi) and Uganda (Entebbe and Kampala). The studies followed hypothetical procedures of an HIV vaccine efficacy trial and aimed to enroll HIV negative key and vulnerable populations at elevated risk of HIV acquisition. HBV status was the main outcome categorized using Hepatitis B surface antigen (HBsAg) and total Hepatitis B core antibody (HBcAb). Baseline characteristics potentially associated with never being infected were analyzed using logistic regression.

RESULTS

We screened 1,366 participants with mean age (SD) 28.7 (7.3) years. Overall, 46.6% were from Entebbe, 50.7% had secondary or higher level of education, 76.4% had informal high-risk jobs and 56.3% were male. Kampala had only female participants contributing 60.6% of females screened. Of the screened participants, 94.7% and 3.4% were negative and positive for HBsAg respectively. The prevalence on HBV infection was 3.9% among males and 2.8% among females while prevalence by site was: Entebbe (4.9%); Kampala (4.1%) and Nairobi (0.3%). The highest HBV prevalence was found among participants aged 25-29-years (5.2%), those with primary level education (4.5%), and those in informal low risk jobs (6.5%). Considering 1265 participants with complete data on HBsAg and HBcAb-Total, HBV status was never infected (67.9%), past infection (28.5%), chronic infection (3.2%) and acute infection (0.5%). Of 859 who were never infected, 685 (79.7%) were tested for anti-HBs titers of whom 60 (8.8%) had titers >10IU/L (immune due to vaccination). The odds of never being HBV infected were lower among older individuals 25-29 years (AOR 0.51; 95%CI 0.36-0.71) and ≥30 years (AOR 0.35; 95% CI 0.25-0.49). The odds were higher among participants with informal high-risk jobs from Kampala (AOR 2.21; 95% CI 1.41-3.47) and Nairobi (AOR 2.61; 95% CI 1.72-4.00) compared to those from Entebbe.

CONCLUSION

HBV prevalence and immunity due to vaccination were low among HIV negative individuals who are eligible for HIV vaccine trials and prevalence varies by age, education level and main occupation. Younger individuals and those recruited from existing cohorts/ clinics have a higher likelihood of having no prior HBV infection. HIV prevention intervention trials are a platform to identify individuals that need HBV vaccination.

Knowledge of Human Mpox (Monkeypox) and Attitude towards Mpox Vaccination among Male Sex Workers in China: A Cross-Sectional Study

BACKGROUND

Re-emerging human mpox (previously known as monkeypox) is spreading around the world. According to existing studies, the current mpox pandemic mainly affects men who have sex with men (MSM), including male sex workers (MSW). Our study aimed to assess mpox knowledge and attitude towards mpox vaccination among MSW in China.

METHODS

A web-based, cross-sectional survey was conducted in August 2022. We collected participants' socio-demographic characteristics and knowledge with 15 knowledge items related to mpox. Modified Bloom's cut-off points of 80% (total score > 12) was used to indicate good knowledge. Multivariable regression analysis was used to assess factors of mpox knowledge and attitude towards mpox vaccination.

RESULTS

A total of 154 MSW were recruited (age: median = 22, interquartile range, IQR = 12). Of the 154 MSW, 49.4% had good knowledge of mpox, and 63.0% were willing to be vaccinated against mpox. We found that good knowledge was associated with being single [adjusted odds ratio (AOR) = 2.46, 95% confident interval (CI) (1.22-4.87)], being unemployed [5.01, 1.21-20.70] and willingness to be vaccinated [2.51, 1.14-5.54]. Willingness to get vaccinated was related to age [1.06, 1.00-1.12], chronic diseases history [8.53, 1.01-71.68], and agreement with "priority for high-risk groups if mpox vaccine is in short supply" [2.57, 1.01-6.54].

CONCLUSIONS

We found that MSW had suboptimal mpox knowledge and a high willingness to be vaccinated against mpox. MSW who are single and willing to be vaccinated may have good knowledge of mpox. These findings underscore the necessity of providing health education on mpox among MSW. When the mpox vaccine is in short supply, priority should be given to high-risk groups, such as MSW.

Feasibility of conducting HIV prevention trials among key populations in Nairobi, Kenya

OBJECTIVE

To assess the feasibility of conducting HIV prevention trials among key populations in Nairobi, Kenya.

BACKGROUND

HIV prevention trials require the inclusion of those at high risk of HIV infection and their informed decision to take part and remain in the clinical trial to the end is crucial. In Kenya key populations including men who have sex with men (MSM) and female sex workers (FSW) are, disproportionately, at high risk of HIV infection when compared to the general population. Few trials testing biomedical prevention products against HIV have enrolled Kenyan FSW and MSM.

METHODS

We performed simulated vaccine efficacy trial (SiVET) using licensed hepatitis B vaccines as substitutes for a HIV vaccine candidate and included randomization for those immune to hep B. The SiVET was an observational study designed to mimic the rigors of a clinical trial; we assessed HIV risk, provided risk counselling and prevention tools and performed HIV testing at baseline and periodically until the end of the trial. MSM and FSW were enrolled at a ratio of 4:1. Volunteers were assigned to either hepatitis B vaccine or placebo.

RESULTS

Recruitment took approximately 24 months between Sep 2015 and Sep 2017. Of the 368 volunteers screened, 250 (200 MSM and 50 FSW) were enrolled. Reasons for exclusion at screening included: being positive for HIV (n = 7), hepatitis (n = 14), other pre-existing medical conditions (n = 41), eligible but chose not to enrol (n = 47). Most of the volunteers adhered to study procedures and attended their study visits within the study window. These include volunteers who received the second vaccination 244 (98%), the third vaccination 228 (91%) and, the final study visit 217 (87%). The reasons volunteers discontinued from the study early included: relocation and loss to follow up (n = 14). A total of 8 cases of HIV infection were observed in 174.5 Person Years at Risk (PYAR), all among MSM, including 5 seroconversions identified at the last study visit, for a HIV incidence of 4.58 cases/ 100 PYAR, among MSM enrolled in the study.

CONCLUSION

Our findings suggest that it is possible to conduct HIV prevention trials among key populations in Nairobi with a good adherence to a vaccine efficacy trial schedule. Despite HIV prevention efforts, we also noted a high incidence of HIV infection. This demonstrates the need for effective HIV prevention products in these populations.

Personal experiences following acquiring HIV infection while volunteering in Phase I/II HIV vaccine trials: A qualitative study from Tanzania

BACKGROUND

Participation in HIV vaccine trials is an essential step towards development of an effective preventive vaccine. A Phase I/II HIV vaccine trial enrolls volunteers at low risk of acquiring HIV infection, however a few may still become infected. Understanding the experiences of volunteers who acquired HIV infection while participating in such trials is essential for future research. Here, we describe experiences of HIV infected volunteers in Phase I/II HIV vaccine trials conducted in urban Tanzania.

MATERIALS AND METHODS

We used a case study design. In-depth interviews were conducted with four participants who became HIV infected during long follow-up visits after completion of vaccination schedules in a Phase I/II trial. Between 3 and 8 years after HIV positive diagnosis, each participant was interviewed at three time points within a two-year interval so as to allow for accumulation of experiences and cross-checking the emerging constructs. Data was analyzed using a qualitative data analysis framework.

RESULTS

Analysis revealed that participation in HIV vaccine trials involves balancing controversies and the spirit of informed decision. The participants declared that they did not acquire HIV from the experimental vaccine. Disclosure of HIV status within the family was gender specific. Men were hesitant to disclose their HIV status to their sexual partners fearing for the consequences. Women's attempt to disclose their HIV status yielded negative reactions from the sexual partners. The acquired knowledge from the HIV vaccine research enabled the participants to cope with the uncertainties and their health status.

CONCLUSIONS

The knowledge acquired during the Phase I/II HIV vaccine trial appears to be an essential resource to cope with uncertainties post research. The HIV vaccine trial implementers need to understand the challenges the volunteers may confront after the trial while coping with their health status. Longitudinal studies are essential to trace the effects of uncertainties to the individual participants.

Predictors of Loss to Follow-Up in an HIV Vaccine Preparedness Study in Masaka, Uganda

Background: High participant retention is essential to achieve adequate statistical power for clinical trials. We assessed participant retention and predictors of loss to follow-up (LTFU) in an HIV vaccine-preparedness study in Masaka, Uganda. Methods: Between July 2018 and March 2021, HIV sero-negative adults (18–45 years) at high risk of HIV infection were identified through HIV counselling and testing (HCT) from sex-work hotspots along the trans-African highway and fishing communities along the shores of Lake Victoria. Study procedures included collection of baseline socio-demographic data, quarterly HCT, and 6-monthly collection of sexual risk behaviour data. Retention strategies included collection of detailed locator data, short clinic visits (1–2 h), flexible reimbursement for transport costs, immediate (≤7 days) follow-up of missed visits via phone and/or home visits, and community engagement meetings. LTFU was defined as missing ≥2 sequential study visits. Poisson regression models were used to identify baseline factors associated with LTFU. Results: 672 participants were included in this analysis. Of these, 336 (50%) were female and 390 (58%) were ≤24 years. The median follow-up time was 11 months (range: 0–31 months). A total 214 (32%) participants were LTFU over 607.8 person-years of observation (PYO), a rate of 35.2/100 PYO. LTFU was higher in younger participants (18–24 years versus 35–45 years, adjusted rate ratio (aRR) = 1.29, 95% confidence interval (CI) 0.80–2.11), although this difference was not significant. Female sex (aRR = 2.07, 95% CI, 1.51–2.84), and recreational drug use (aRR = 1.61, 95% CI, 1.12–2.34) were significantly associated with increased LTFU. Engagement in transactional sex was associated with increased LTFU (aRR = 1.36, 95% CI, 0.97–1.90) but this difference was not significant. LTFU was higher in 2020–2021 (the period of COVID-19 restrictions) compared to 2018–2019 (aRR = 1.54, 1.17–2.03). Being Muslim or other (aRR = 0.68, 95% CI 0.47–0.97) and self-identification as a sex worker (aRR = 0.47, 95% CI, 0.31–0.72) were associated with reduced LTFU. Conclusion: We observed a high LTFU rate in this cohort. LTFU was highest among women, younger persons, recreational drug users, and persons who engage in transactional sex. Efforts to design retention strategies should focus on these subpopulations.

Willingness of female sex workers in Kampala, Uganda to participate in future HIV vaccine trials: a case control study

Background

We anticipate large efficacy trials of novel HIV vaccines that have shown acceptable safety profiles. We determined willingness to participate (WTP) in future HIV vaccine efficacy trials among HIV negative female sex workers (FSWs) in Kampala Uganda.

Methods

We conducted a case control study in the Good Health for Women Project cohort. Cases received HIV prevention services and, enrolled in a 12-month simulated vaccine efficacy trial (SiVET) that used Hepatitis B vaccine; they underwent vaccine trial procedures as would be in an actual trial. Controls received similar health services but did not enroll in SiVET. We matched cases and controls (ratio 2:1) for age and duration in the cohort. We described a hypothetical HIV vaccine trial to cases (after 9 months in SiVET) and controls including trial attributes: randomization, delaying pregnancy, frequent blood draws (80-100mls) and study visits for 3 years. We compared WTP and willingness for vaccine trial attributes by case/control using chi-squared or Fisher’s exact tests and fitted conditional logistic regression models to determine independent predictors of WTP.

Results

We analyzed data for 311 volunteers (219 cases, 92 controls); median age 27 years (IQR: 23–32), 39.9% had ≥secondary education, 57.9% had sex work as their main job and 81.9% used illicit drugs. Compared to controls, more cases had lived in the community for > 1 year, (85.4% vs 64.1%; p < 0.001) and fewer cases reported illicit drug use in the past 3 months, (79.0% vs 89.1%; p = 0.03). Overall, 278 (89.4%) volunteers expressed WTP in an HIV vaccine trial, the most common reason being hope of protection against HIV. More cases than controls (58.2% vs 44.7%) did not need to consult anyone before trial participation (p = 0.03); cases were more willing to delay pregnancy (99.0% vs 94.0%; p = 0.03). Combining vaccine trial attributes, 249 (89.6%) of the 278 accepted all attributes. After controlling for case/ control status women with secondary education or higher expressed less WTP (aOR 0.17; 95% CI 0.04–0.80).

Conclusion

FSWs in Kampala demonstrated high WTP. Prior experience with trial requirements like contraception may improve their uptake during actual trials. Family involvement is important for those without prior trial experience.

What motivates or demotivates injecting drug users to participate in hypothetical HIV vaccine efficacy trials? A qualitative study from urban Tanzania

Background:

HIV vaccine efficacy trials require the active participation of volunteers who are committed and adherent to the study protocol. However, information about the influence of Injecting Drug Users (IDUs) to participate in HIV vaccine efficacy trials in low-income countries is inadequate. The present study explored the factors that motivate or hinder IDUs from participating in HIV vaccine efficacy trials in Dar es Salaam, Tanzania.

Methods:

A qualitative descriptive study design was employed among IDUs at Muhimbili National Hospital (MNH). A purposeful sampling technique was used to recruit the participants. Three (3) focus group discussions (FGDs) and 10 In-Depth Interviews (IDIs) were used to collect the data. The data from participants were audio-recorded, transcribed, and analysed using the content analysis approach.

Findings:

The participants reported that altruism and the desire to reduce risks of HIV infection were the motivators to participate in hypothetical HIV vaccine trials. In addition, participants reported to consult close relatives towards motivation to participate in the vaccine trial. In contrast, the perceived fear of vaccine side effects, lack of information about HIV vaccine studies, and HIV-related stigma towards participants were described as barriers to participate in the HIV vaccine trials.

Conclusion:

Participation in a hypothetical HIV vaccine trial among IDUs is influenced by positive and negative factors. Actual recruitment plans could be made through a better explanation of HIV vaccine trials, the expected individual and collective benefits associated with the trials. Community involvement and sensitisation is likely to enhance participation in future HIV vaccine trials in Tanzania.