KOKen Ondeng'E

Ken Ondeng'E

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Ken Ondeng'E has a total of 82 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Longitudinal Effects of a Smartphone Game (Tumaini) for HIV Prevention Among Kenyan Adolescents: 45-Month Trajectories of Condom Use–Related Proximal Outcomes From a Randomized Controlled Trial

    by Kate Winskell, Gaëlle Sabben, Haowen Qin, Calvin Mbeda, Sophie Goldenberg, Ken Ondeng'E, Richard Ndivo, Judith Arego, Xinwei He, Robert A Bednarczyk, et al.

    Background: African adolescents and young adults account for a disproportionate number of new HIV infections. There is an urgent need to identify scalable and cost-effective behavioral HIV prevention strategies for this population. Using a condom at first sex is associated with a higher likelihood of consistent use later. Tumaini (“Hope for the Future” in Swahili; Emory University) is a choose-your-own-adventure smartphone game that has been shown to reduce the risk of unprotected first sex by end line in a 45-month randomized controlled trial in western Kenya. Objective: This study aimed to assess the impact of Tumaini on proximal outcomes related to condom use at first sex (specifically, behavioral intentions, self-efficacy, attitudes, and knowledge) longitudinally across mid-adolescence in the above trial. Methods: Adolescent participants (n=996, mean baseline age 14, SD 0.56 years) were randomized 1:1 to receive either a smartphone loaded with Tumaini or an attention-control math game for 5 to 7 weeks at 3 time points (mean age 14.0, SD 0.56; 15.3, SD 0.55; and 16.0, SD 0.56 years, respectively). They completed a behavioral survey at 13 time points, through mean age 17.7 (SD 0.56) years. Using generalized estimating equations and controlling for age at baseline, we modeled mean scores (overall and stratified by gender) on a range of condom-related survey items over time to assess mean differences at specific time points. We applied appropriate Bonferroni corrections to inferences about cross-arm differences in mean changes relative to baseline at 4 time points (after each intervention period and at end line; α=.05/4) and within-arm mean changes relative to baseline at each of the 12 post-baseline time points (α=.05/12). Analyses were conducted as intent-to-treat. Results: At end line, 97.8% (n=974) of the sample had been retained. Participants in both arms dedicated a mean total of >30 hours to their assigned game. There was significant improvement across all condom-related proximal outcomes in the intervention arm relative to the control arm immediately after initial intervention exposure. For almost all outcomes, a significant cross-arm difference was also present at end line and for most outcomes at the 2 intervening comparison time points. Some outcomes saw stronger intervention effects on female participants (eg, self-efficacy to refuse unprotected sex) or male participants (eg, knowledge that condoms are an effective way to prevent HIV). In each arm, intention to use a condom at first sex was consistently higher among male participants; however, female intervention-arm scores overtook male control-arm scores following initial intervention exposure. Conclusions: Tumaini significantly improved theory-based proximal outcomes related to condom use, with effects sustained 45 months post initial exposure and 16 months post most recent exposure. Adolescents benefited from even short-term exposure, though repeated exposure generally sustained and reinforced intervention effects. As access to smartphones increases, Tumaini has potential for high scalability and impact on condom-related outcomes. Trial Registration: ClinicalTrials.gov NCT04437667; https://clinicaltrials.gov/study/NCT04437667 International Registered Report Identifier (IRRID): RR2-10.2196/35117


  • Open Access

    Longitudinal Effects of a Smartphone Game (Tumaini) for HIV Prevention Among Kenyan Adolescents: 45-Month Trajectories of Condom Use–Related Proximal Outcomes From a Randomized Controlled Trial (Preprint)

    by Kate Winskell, Gaëlle Sabben, Haowen Qin, Calvin Mbeda, Sophie Goldenberg, Ken Ondeng'E, Richard Ndivo, Judith Arego, Xinwei He, Robert A Bednarczyk, et al.

    BACKGROUND African adolescents and young adults account for a disproportionate number of new HIV infections. There is an urgent need to identify scalable and cost-effective behavioral HIV prevention strategies for this population. Using a condom at first sex is associated with a higher likelihood of consistent use later. Tumaini (“Hope for the Future” in Swahili; Emory University) is a choose-your-own-adventure smartphone game that has been shown to reduce the risk of unprotected first sex by end line in a 45-month randomized controlled trial in western Kenya. OBJECTIVE This study aimed to assess the impact of Tumaini on proximal outcomes related to condom use at first sex (specifically, behavioral intentions, self-efficacy, attitudes, and knowledge) longitudinally across mid-adolescence in the above trial. METHODS Adolescent participants (n=996, mean baseline age 14, SD 0.56 years) were randomized 1:1 to receive either a smartphone loaded with Tumaini or an attention-control math game for 5 to 7 weeks at 3 time points (mean age 14.0, SD 0.56; 15.3, SD 0.55; and 16.0, SD 0.56 years, respectively). They completed a behavioral survey at 13 time points, through mean age 17.7 (SD 0.56) years. Using generalized estimating equations and controlling for age at baseline, we modeled mean scores (overall and stratified by gender) on a range of condom-related survey items over time to assess mean differences at specific time points. We applied appropriate Bonferroni corrections to inferences about cross-arm differences in mean changes relative to baseline at 4 time points (after each intervention period and at end line; α=.05/4) and within-arm mean changes relative to baseline at each of the 12 post-baseline time points (α=.05/12). Analyses were conducted as intent-to-treat. RESULTS At end line, 97.8% (n=974) of the sample had been retained. Participants in both arms dedicated a mean total of >30 hours to their assigned game. There was significant improvement across all condom-related proximal outcomes in the intervention arm relative to the control arm immediately after initial intervention exposure. For almost all outcomes, a significant cross-arm difference was also present at end line and for most outcomes at the 2 intervening comparison time points. Some outcomes saw stronger intervention effects on female participants (eg, self-efficacy to refuse unprotected sex) or male participants (eg, knowledge that condoms are an effective way to prevent HIV). In each arm, intention to use a condom at first sex was consistently higher among male participants; however, female intervention-arm scores overtook male control-arm scores following initial intervention exposure. CONCLUSIONS Tumaini significantly improved theory-based proximal outcomes related to condom use, with effects sustained 45 months post initial exposure and 16 months post most recent exposure. Adolescents benefited from even short-term exposure, though repeated exposure generally sustained and reinforced intervention effects. As access to smartphones increases, Tumaini has potential for high scalability and impact on condom-related outcomes. CLINICALTRIAL ClinicalTrials.gov NCT04437667; https://clinicaltrials.gov/study/NCT04437667 INTERNATIONAL REGISTERED REPORT RR2-10.2196/35117

  • Bisexuality among Men who have Sex with Men in Sub-Saharan Africa: Findings from the HPTN 075 Study

    by Ken Ondeng’e, Xu Guo, Calvin Mbeda, David Schnabel, Ravindre Panchia, Karen Dominguez, Sufia Dadabhai, Erica L. Hamilton, Theo G. M. Sandfort

    Studies among men who have sex with men (MSM) in sub-Saharan Africa (SSA) focus mainly on HIV epidemiology, revealing little about the diversity within this population. We utilized data from the HIV Prevention Trials Network (HPTN) 075 study, to explore demographic and psychosexual characteristics of MSM in SSA who also have sex with women. Persons included in the analyses were aged 18–44 years and assigned male sex at birth and identified as male, reported anal sex with a man in the past 3 months, and had enrolled at one of four study sites (Kisumu, Kenya; Blantyre, Malawi; Cape Town and Soweto, South Africa). Nearly a quarter of the participants had recently engaged in sex with both men and women (MSMW). These men differed in terms of demographic and psychosexual characteristics, and sexual behavior from men who only had had sex with men (MSME). Compared to the latter, MSMW were more likely to prefer the insertive sexual role, reported more sexual partners in the past three months, and had more instances of condomless insertive anal intercourse with a man. These findings suggest that men who have sex with both men and women have specific characteristics and need tailored interventions that take their specific needs into account.


  • Open Access

    Sexual behaviour among Kenyan adolescents enrolled in an efficacy trial of a smartphone game to prevent HIV: a cross-sectional analysis of baseline data

    by Victor Mudhune, Kate Winskell, Robert A. Bednarczyk, Ken Ondenge, Calvin Mbeda, Emily Kerubo, Richard Ndivo, Judith Arego, Marissa Morales, Brianna Halliburton, et al.

    Sexual behaviour of adolescents is contextual, with various determinants affecting sexual activity and age of sexual debut. Insight into sexual activity among young adolescents has the potential to influence appropriate sexual and reproductive health interventions. For this analysis, adolescents were recruited as part of the Tumaini smartphone game efficacy trial. Data collection included a self-administered behavioural survey and blood test for HIV and HSV-2. Descriptive statistics were calculated for demographics and measures of sexual behaviour and behavioural intent based on gender and sexual experience, with associations assessed using chi-square tests, t-tests and Wilcoxon rank sum tests as appropriate. We enrolled 996 adolescents, mean age 14 years and 2.2% HSV-2 positivity. Overall, 15% of the adolescents were sexually experienced, this being associated with lower socio-economic status (p = 0.01), household food insecurity (p = 0.008), a living situation without both parents (p < 0.01), substance use (p = 0.02), no adult conversation about future goals (p = 0.003), conversations about condoms (p = 0.01), with some gender disparity within these factors. Among those sexually experienced, 21.7% reported unwilling sex; 17.5% had engaged in transactional sex; 57.8% had willing first sex, of whom 60.9% reported no condom use. Among those abstaining, female adolescents were less likely to contemplate condom use at first sex (p = 0.006). Our findings determine that young sexually active adolescents are likely engaging in unprotected sex and having unwilling sexual experiences. Socio-economic status, living situation and parental monitoring remain significant factors associated with sexual experience among young adolescents. In this context, early adolescence is an opportunity to provide age- and developmentally appropriate education about safer sex practices.Trial registration: ClinicalTrials.gov identifier: NCT04437667.


  • Open Access

    Understanding ART Adherence among Adolescent Girls and Young Women in Western Kenya: A Cross-Sectional Study of Barriers and Facilitators

    by Jonathan Altamirano, Isdorah A. Odero, Mevis Omollo, Eucabeth Awuonda, Ken Ondeng’e, Jennifer L. Kang, Rasika Behl, Richard Ndivo, Michael Baiocchi, Hellen C. Barsosio, et al.

    Background: HIV remains a leading cause of death for adolescent girls and young women (AGYW) in sub-Saharan Africa. This population has a high incidence of HIV and other comorbidities, such as experiencing violence, and low antiretroviral therapy (ART) adherence. To reach global HIV goals, data are needed on the specific adherence barriers for AGYW living with HIV, so interventions can be targeted effectively. Methods: Cross-sectional data were collected at urban and rural health facilities in and around Kisumu County, western Kenya, from January to June 2022, from AGYW 15–24 years of age who were living with HIV. Surveys included questions on intimate partner violence, mental health issues, food security, and orphanhood. Adherence was categorized using viral load testing where available and the Center for Adherence Support Evaluation (CASE) adherence index otherwise. Logistic regression was used to assess associations between potential explanatory variables and adherence. Findings: In total, 309 AGYW participated. AGYW with experiences of emotional violence (Odds Ratio [OR] = 1.94, 95% Confidence Interval [CI] = 1.03–3.66), moderate or severe depression (OR = 3.19, 95% CI = 1.47–6.94), and/or substance use (OR = 2.71, 95% CI = 1.24–5.92) had significantly higher odds of poor adherence when compared to AGYW without these respective experiences. Physical and sexual violence, food insecurity, and orphanhood were not associated with poor adherence in this cohort. Interpretation: Elucidating the risk factors associated with poor adherence among AGYW living with HIV allows us to identify potential targets for future interventions to improve ART adherence and HIV care outcomes. Mental health and violence prevention interventions, including combination interventions, may prove to be promising approaches.


  • Open Access

    Determinants of COVID-19 Vaccine Acceptability among Healthcare Workers in Kenya—A Mixed Methods Analysis

    by Victor Mudhune, Ken Ondeng’e, Fanuel Otieno, Derick B. Otieno, Collins M. Bulinda, Ikechukwu Okpe, Sarah Nabia, Naor Bar-Zeev, Omondi Otieno, Chizoba Wonodi

    Healthcare workers (HCWs) were a priority group for COVID-19 vaccination. Adopting the World Health Organization’s 3C and the expanded 5C vaccine hesitancy models, we assessed the factors associated with COVID-19 vaccine acceptability among HCWs in Kenya. In a mixed methods study, respondents were from eight selected counties across the country. An online survey (n = 746), key informant interviews (n = 18) and focus group discussions (n = 3) were conducted. The data were analyzed concurrently. Quantitative data showed that all the 3C antecedents were strong predictors of vaccine acceptability. The association of vaccine acceptability was strongest with convenience (aOR 20.13, 95% CI 9.01–44.96), then complacency (aOR 10.15, 95% CI 4.63–22.21) and confidence (aOR 6.37, 95% CI 2.90–14.02). Marital status was a significant independent factor associated with vaccine acceptability (aOR 2.70, 95% CI 1.20–6.08). Qualitatively, convenience presented as the no-cost availability of vaccines at the health facilities, whereas non-complacency manifested from the first-hand observed experience of COVID cases, and the need to protect oneself and family members. Confidence was mainly attributed to increased knowledge, resulting from multiple training sessions and trust in regulatory authorities. Other social factors including workplace pressure, religion and misinformation had a role in influencing HCW vaccination decisions. In the background of a pandemic, the 3C model is a strong predictor of vaccine acceptability, and making the vaccines easily available and convenient to HCWs significantly impacts their uptake.


  • Open Access

    The Efficacy of a Smartphone Game to Prevent HIV Among Young Africans: Protocol for a Randomized Controlled Trial in the Context of COVID-19

    by Victor Mudhune, Gaëlle Sabben, Ken Ondenge, Calvin Mbeda, Marissa Morales, Robert H Lyles, Judith Arego, Richard Ndivo, Robert A Bednarczyk, Kelli Komro, et al.

    Background: Adolescents contribute slightly less than one-third of all new HIV infections in sub-Saharan Africa. There is a need for more effective intervention approaches to help young adolescents safely navigate through adolescence and into adulthood. We are assessing the efficacy of Tumaini, a smartphone game designed to prevent HIV among young Africans. Against the background of COVID-19, meaningful alteration of the research protocol was necessary to ensure successful implementation and retention of the study participants in ongoing research. Objective: The objective of our protocol is to determine (1) if Tumaini delays sexual debut and increases condom use at first sex and (2) whether it influences behavioral mediators of early and unprotected sex. Methods: Participants were recruited from Kisumu County in Western Kenya. This study is a 2-arm, individual-randomized controlled trial that enrolled 1004 adolescents aged between 12 years and 15 years. The intervention arm participants are playing Tumaini, while the control arm is provided with Brainilis, a commercially available control game. The study period will last 45 months. At baseline, participants in both arms completed a baseline survey and biological testing for HIV and herpes simplex virus, type 2 (HSV-2); participants will have annual game play periods in years 1-3. They will also complete a total of 12 follow-up surveys. At endline, repeat biological testing will be conducted. Protocol adaptations were necessitated by the COVID-19 pandemic and implemented in accordance with local public health guidelines. Results: Participants were enrolled between October 2020 and November 2020. We plan to complete study procedures in September 2024. The enrolled participant sample was 50.1% (499/996) female and had a mean age of 14.0 (SD 0.6) years. Conclusions: This ongoing research demonstrates that, with appropriate revisions to planned protocol activities guided by the need to maintain study integrity, protect both study participants and staff, and adhere to institutional review board and local health authority guidelines, human subject research is possible in the context of a global pandemic. If the trial demonstrates efficacy, Tumaini would provide an alternative, remote means of delivering age-appropriate education to adolescents on safer sex, HIV prevention, and effective life skills on a highly scalable, low-cost, and culturally adaptable platform. Trial Registration: ClinicalTrials.gov NCT04437667; https://clinicaltrials.gov/ct2/show/NCT04437667 International Registered Report Identifier (IRRID): DERR1-10.2196/35117


  • Open Access

    The Efficacy of a Smartphone Game to Prevent HIV Among Young Africans: Protocol for a Randomized Controlled Trial in the Context of COVID-19 (Preprint)

    by Victor Mudhune, Gaëlle Sabben, Ken Ondenge, Calvin Mbeda, Marissa Morales, Robert H Lyles, Judith Arego, Richard Ndivo, Robert A Bednarczyk, Kelli Komro, et al.

    BACKGROUND Adolescents contribute slightly less than one-third of all new HIV infections in sub-Saharan Africa. There is a need for more effective intervention approaches to help young adolescents safely navigate through adolescence and into adulthood. We are assessing the efficacy of Tumaini, a smartphone game designed to prevent HIV among young Africans. Against the background of COVID-19, meaningful alteration of the research protocol was necessary to ensure successful implementation and retention of the study participants in ongoing research. OBJECTIVE The objective of our protocol is to determine (1) if Tumaini delays sexual debut and increases condom use at first sex and (2) whether it influences behavioral mediators of early and unprotected sex. METHODS Participants were recruited from Kisumu County in Western Kenya. This study is a 2-arm, individual-randomized controlled trial that enrolled 1004 adolescents aged between 12 years and 15 years. The intervention arm participants are playing Tumaini, while the control arm is provided with Brainilis, a commercially available control game. The study period will last 45 months. At baseline, participants in both arms completed a baseline survey and biological testing for HIV and herpes simplex virus, type 2 (HSV-2); participants will have annual game play periods in years 1-3. They will also complete a total of 12 follow-up surveys. At endline, repeat biological testing will be conducted. Protocol adaptations were necessitated by the COVID-19 pandemic and implemented in accordance with local public health guidelines. RESULTS Participants were enrolled between October 2020 and November 2020. We plan to complete study procedures in September 2024. The enrolled participant sample was 50.1% (499/996) female and had a mean age of 14.0 (SD 0.6) years. CONCLUSIONS This ongoing research demonstrates that, with appropriate revisions to planned protocol activities guided by the need to maintain study integrity, protect both study participants and staff, and adhere to institutional review board and local health authority guidelines, human subject research is possible in the context of a global pandemic. If the trial demonstrates efficacy, Tumaini would provide an alternative, remote means of delivering age-appropriate education to adolescents on safer sex, HIV prevention, and effective life skills on a highly scalable, low-cost, and culturally adaptable platform. CLINICALTRIAL ClinicalTrials.gov NCT04437667; https://clinicaltrials.gov/ct2/show/NCT04437667 INTERNATIONAL REGISTERED REPORT DERR1-10.2196/35117

  • Factors associated with age of first sex among women screened for an observational contraceptive vaginal ring study in Kisumu, Kenya, 2014

    by Ken Ondenge, Roman Gvetadze, George Otieno, Deborah A. Gust, Eleanor McLellan-Lemal

    Sex at an early age can have later life negative health outcomes. Insights on early sexual activity may help in the development of future health-promotion products and interventions related to pregnancy and sexually transmitted infections (STIs) prevention. Among Kenyan women participating in a contraceptive vaginal ring study, we determined: (1) the proportion with first sex at <= 15 years (early sex) and (2) factors associated with early sex. Baseline data collection and testing for pregnancy, STIs, and HIV were undertaken. A log-binomial or a modified Poisson regression was used to estimate univariable prevalence ratios and multivariable adjusted prevalence ratios (aPRs). Among 332 women aged 18-34 years, the median age of first sex was 16 years, with 40.1% experiencing early sex. Overall, 29.8% reported an older first sex partner (>= 5 years); 83.9% indicated lack of readiness or intentions at first sex; and 56.2% received money, gifts, or favors as part of first sex. Early sex was more prevalent among inherited widows (a Luo cultural practice, aPR 1.49), gift recipients (aPR 1.38), women with a forced/unwanted sex history (aPR 1.42), or those with a partner of unknown or positive HIV status in the past 3 months (aPR 1.45). Sex before or at the age 15 may be associated with higher sexual risk behaviors. Complex power and gender relations may additionally influence exposure to sexual risk in our research setting.


  • Open Access

    A Smartphone Game to Prevent HIV Among Young Africans (Tumaini): Assessing Intervention and Study Acceptability Among Adolescents and Their Parents in a Randomized Controlled Trial

    by Gaëlle Sabben, Victor Mudhune, Ken Ondeng'E, Isdorah Odero, Richard Ndivo, Victor Akelo, Kate Winskell

    Mobile and tablet apps, ubiquitous and pervasive computing, wearable computing and domotics for health.