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Dive into the research topics where Theodorus Sandfort is active.

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Featured researches published by Theodorus Sandfort.


Journal of Acquired Immune Deficiency Syndromes | 2013

Overcoming biological, behavioral, and structural vulnerabilities: New directions in research to decrease HIV transmission in men who have sex with men

Kenneth H. Mayer; Darrell P. Wheeler; Linda-Gail Bekker; Beatriz Grinsztejn; Robert H. Remien; Theodorus Sandfort; Chris Beyrer

Abstract:Men who have sex with men (MSM), including transgender women, comprise a heterogeneous group of individuals whose sexual behaviors and gender identities may vary widely between cultures and among individuals. Their sources of increased vulnerability to HIV are diverse, including the increased efficiency of HIV transmission via unprotected anal intercourse, sexual role versatility, asymptomatic sexually transmitted infections, and behavioral factors that may be associated with condomless sex with multiple partners. Societal stigmatization of homosexual behavior and gender nonconformity may result in internalized negative feelings that lead to depression, other affective disorders, and substance use, which in turn are associated with increased risk-taking behaviors. Social stigma and punitive civil environments may lead to delays in seeking HIV and sexually transmitted disease screening, and later initiation of antiretroviral therapy. The iPrEX study demonstrated that chemoprophylaxis can decrease HIV acquisition in MSM, and the HIV prevention trials network 052 study established the biological plausibility that earlier initiation of highly active antiretroviral therapy can decrease HIV transmission to uninfected partners. Despite these advances, MSM remain among the most significantly HIV-affected population in resource-rich and limited settings. New studies will integrate enhanced understanding of the biology of enhanced rectal transmission of HIV and the focused use of antiretrovirals for prevention with culturally tailored approaches that address the potentiating social and behavioral factors associated with enhanced HIV spread among MSM.


PLOS ONE | 2013

Forced sexual experiences as risk factor for self-reported HIV infection among southern African lesbian and bisexual women.

Theodorus Sandfort; Linda R. M. Baumann; Zethu Matebeni; Vasu Reddy; Ian Southey-Swartz

Even though women who have sex with women are usually understood to be at no or very low risk for HIV infection, we explored whether lesbian and bisexual women in a geographical area with high HIV prevalence (Southern Africa) get tested for HIV and whether, among those women who get tested, there are women who live with HIV/AIDS. The study was conducted in collaboration with community-based organizations in Botswana, Namibia, South Africa and Zimbabwe. Data were collected via written surveys of women who in the preceding year had had sex with a woman (18 years and older; N = 591). Most participating women identified as lesbian and black. Almost half of the women (47.2%) reported ever having had consensual heterosexual sex. Engagement in transactional sex (lifetime) was reported by 18.6% of all women. Forced sex by men or women was reported by 31.1% of all women. A large proportion of the women reported to ever have been tested for HIV (78.3%); number of lifetime female and male partners was independently associated with having been tested; women who had engaged in transactional sex with women only or with women and men were less likely to have been tested. Self-reported HIV prevalence among tested women who knew their serostatus was 9.6%. Besides age, the sole independent predictor of a positive serostatus was having experienced forced sex by men, by women, or by both men and women. Study findings indicate that despite the image of invulnerability, HIV/AIDS is a reality for lesbian and bisexual women in Southern Africa. Surprisingly, it is not sex with men per se, but rather forced sex that is the important risk factor for self-reported HIV infection among the participating women. HIV/AIDS policy should also address the needs of lesbian, bisexual and other women who have sex with women.


PLOS ONE | 2014

The Mpumalanga Men's Study (MPMS): results of a baseline biological and behavioral HIV surveillance survey in two MSM communities in South Africa.

Tim Lane; Thomas Osmand; Alexander Marr; Starley B. Shade; Kristin Dunkle; Theodorus Sandfort; Helen Struthers; Susan M. Kegeles; James McIntyre

The Mpumalanga Mens Study (MPMS) is the assessment of the Project Boithato HIV prevention intervention for South African MSM. Boithato aims to increase consistent condom use, regular testing for HIV-negative MSM, and linkage to care for HIV-positive MSM. The MPMS baseline examined HIV prevalence and associated risk behaviors, and testing, care, and treatment behaviors among MSM in Gert Sibande and Ehlanzeni districts in Mpumalanga province, South Africa in order to effectively target intervention activities. We recruited 307 MSM in Gert Sibande and 298 in Ehlanzeni through respondent-driven sampling (RDS) between September 2012-March 2013. RDS-adjusted HIV prevalence estimates are 28.3% (95% CI 21.1%–35.3%) in Gert Sibande, and 13.7% (95% CI 9.1%–19.6%) in Ehlanzeni. Prevalence is significantly higher among MSM over age 25 [57.8% (95% CI 43.1%–72.9%) vs. 17.9% (95% CI 10.6%–23.9%), P<0.001 in Gert Sibande; 34.5% (95%CI 20.5%–56.0%) vs. 9.1% (95% CI 4.6%–13.9%), P<0.001 in Ehlanzeni]. In Gert Sibande, prevalence is higher among self-identified gay and transgender MSM vs. other MSM [39.3% (95%CI, 28.3%–47.9%), P<0.01], inconsistent condom users [38.1% (18.1%–64.2%), P<0.05], those with a current regular male partner [35.0% (27.1%–46.4%), P<0.05], and those with lifetime experience of intimate partner violence with men [40.4%, (95%CI 28.9%–50.9%), P<0.05]. Prevalence of previous HIV testing was 65.8% (95%CI 58.8%–74.0%) in Gert Sibande, and 69.3% (95%CI 61.9%–76.8%) in Ehlanzeni. Regular HIV testing was uncommon [(34.6%, (95%CI 27.9%–41.4%) in Gert Sibande; 31.0% (95%CI 24.9%–37.8%) in Ehlanzeni]. Among HIV-positive participants, few knew their status (28.1% in Gert Sibande and 14.5% in Ehlanzeni), or were appropriately linked to care (18.2% and 11.3%, respectively), or taking antiretroviral therapy (13.6% and 9.6% respectively). MPMS results demonstrate the importance of implementing interventions for MSM to increase consistent condom use, regular HIV testing, and linkage and engagement in care for HIV-infected MSM.


Aids and Behavior | 2018

Interest in Long-Acting Injectable PrEP in a Cohort of Men Who have Sex with Men in China

Kathrine Meyers; Yumeng Wu; Haoyu Qian; Theodorus Sandfort; Xiaojie Huang; Junjie Xu; Jing Zhang; Wei Xia; David V. Glidden; Hao Wu; Hong Shang

Long-acting injectable (LAI) formulations of antiretrovirals (ARVs) as pre-exposure prophylaxis (PrEP) could be an attractive alternative for men who have sex with men (MSM) who are interested in ARV-based biomedical prevention but will not use a daily pill. This study investigated interest in LAI-PrEP in a cohort of MSM in China and characterized how MSM willing to use only injectable PrEP differed from MSM who would use PrEP regardless of modality or not at all. Demographic, behavioral, and risk perception measures were collected and associations investigated. A licensed LAI-PrEP agent would increase the proportion interested in PrEP by 24.5% over oral PrEP alone. Combining interest in oral and injectable PrEP, 78.5% of the sample could be covered if reported interest in PrEP translated into actual uptake. Partnership factors differentiated those who would be willing to use only LAI-PrEP versus any PrEP modality, while higher self-perception of risk was associated with interest in LAI-PrEP versus no PrEP. The addition of a second PrEP modality could yield increased population coverage of PrEP. Social and behavioral research should be undertaken in parallel with clinical development of injectable PrEP agents to identify characteristics of those who are not interested in oral PrEP but would take advantage of ARV-based prevention with the introduction of an injectable product.


Journal of Acquired Immune Deficiency Syndromes | 2017

Substance Use and HIV Risk Among Men Who Have Sex With Men in Africa: A Systematic Review.

Theodorus Sandfort; Justin R Knox; Carolina Alcala; Nabila El-Bassel; Irene Kuo; Laramie R. Smith

Background: Substance use and its relation to HIV risk among men who have sex in Africa, a population at high risk for HIV, has received little attention. Methods: This systematic review summarizes and discusses findings from 68 empirical studies, published between 1980 and 2016 that included data about substance use in men who have sex with men (MSM) in Africa. Results: Substance use has rarely been the primary focus of studies in African MSM. In general, measurement of substance use was suboptimal. Whereas prevalence of alcohol use varied across studies, partly resulting from variety in assessment strategies, it seemed higher than in the general male population across countries. Alcohol use was associated with sexual risk practices, but not with HIV infection. The most frequently reported drug used by African MSM was cannabis. The use of other drugs, such as cocaine and heroin seemed relatively rare, although injection drug use was exceptionally high in a few studies. As alcohol, drugs were regularly used in conjunction with sex. Both alcohol and drug use were often associated with other risk factors for HIV infection, including violence and transactional sex. No interventions were found addressing substance use among African MSM. Conclusions: Given high HIV risk and prevalence in this population, substance use should be studied more in-depth, taking into account the specific social and cultural context. Assessment of substance use practices in this population has to be improved. The available information suggests, though, that there is an urgent need for interventions addressing substance use tailored to the needs of this critical population.


PLOS ONE | 2018

To switch or not to switch: Intentions to switch to injectable PrEP among gay and bisexual men with at least twelve months oral PrEP experience

Kathrine Meyers; Yumeng Wu; Atrina L. Brill; Theodorus Sandfort; Sarit A. Golub

Background Phase III trials of long-acting injectable (LAI) PrEP, currently underway, have great potential for expanding the menu of HIV prevention options. Imagining a future in which multiple PrEP modalities are available to potential users of biomedical HIV prevention, we investigated which factors might help direct a patient-physician shared-decision making process to optimize the choice of biomedical HIV prevention method. Methods Participants (n = 105; ages 19–63; 46.7% men of color) were former participants in a PrEP demonstration project and had taken daily oral PrEP for ≥ 12 months. Participants were given information about LAI PrEP and asked whether they would be interested in switching from oral to LAI PrEP. Participants were also asked about specific pros/cons of LAI PrEP, PrEP attitudes and experiences, and personality factors. Results Two-thirds (66.7%) of current oral PrEP users would switch to LAI PrEP. Intention to switch was associated with product-level and psychosocial factors. Attitudes towards logistical factors (i.e. getting to regular clinic visits for recurring shots) featured more prominently than factors related to the physical experience of PrEP modality (i.e., concerns about injection pain) as motivators for switching. In a multivariate regression model, psychosocial factors including the emotional burden of daily pill taking, deriving a sense of responsibility from PrEP use, and self-identifying as an early adopter, were the strongest predictors of switching. Conclusions These data underscore the importance of attending not only to product-level factors, but also to the logistical and psychological experience of prevention methods for users. Findings have significant implications for the development of patient education materials and patient-provider shared decision aids.


Aids and Behavior | 2018

Accuracy of Self-Reported HIV Status Among African Men and Transgender Women Who Have Sex with Men Who were Screened for Participation in a Research Study: HPTN 075

Jessica M. Fogel; Theodorus Sandfort; Yinfeng Zhang; Xu Guo; William Clarke; Autumn Breaud; Vanessa Cummings; Erica L. Hamilton; Arthur Ogendo; Noel Kayange; Ravindre Panchia; Karen Dominguez; Ying Q. Chen; Susan H. Eshleman

Some HIV-infected individuals in research studies may choose not to disclose knowledge of their HIV status to study staff. We evaluated the accuracy of self-reported HIV status among African men and transgender women who have sex with men and who were screened for a research study. Sixty-seven of 183 HIV-infected participants reported a prior HIV diagnosis. Samples from the remaining 116 participants were tested for antiretroviral (ARV) drugs. Thirty-six of the 116 participants had ARV drugs detected, indicating that they were on antiretroviral treatment; these participants were classified as previously diagnosed based on ARV drug testing. Among participants classified as previously diagnosed, disclosure of a prior HIV diagnosis varied among study sites (p = 0.006) and was more common among those who reported having sex with men only (p = 0.002). ARV drug testing in addition to self-report improves the accuracy for identifying individuals with a prior HIV diagnosis.


Psychology of sexual orientation and gender diversity | 2017

Validation of the Minority Stress Scale among Italian gay and bisexual men.

Andrea Norcini Pala; Francesca Dell'Amore; P Steca; Lauren Clinton; Theodorus Sandfort; Christine Tagliaferri Rael

The experience of sexual orientation stigma (e.g., homophobic discrimination and physical aggression) generates minority stress, a chronic form of psychosocial stress. Minority stress has been shown to have a negative effect on gay and bisexual men’s (GBM’s) mental and physical health, increasing the rates of depression, suicidal ideation, and HIV risk behaviors. In conservative religious settings, such as Italy, sexual orientation stigma can be more frequently and/or more intensively experienced. However, minority stress among Italian GBM remains understudied. The aim of this study was to explore the dimensionality, internal reliability, and convergent validity of the Minority Stress Scale (MSS), a comprehensive instrument designed to assess the manifestations of sexual orientation stigma. The MSS consists of 50 items assessing (a) Structural Stigma, (b) Enacted Stigma, (c) Expectations of Discrimination, (d) Sexual Orientation Concealment, (e) Internalized Homophobia Toward Others, (f) Internalized Homophobia toward Oneself, and (g) Stigma Awareness. We recruited an online sample of 451 Italian GBM to take the MSS. We tested convergent validity using the Perceived Stress Questionnaire. Through exploratory factor analysis, we extracted the 7 theoretical factors and an additional 3-item factor assessing Expectations of Discrimination From Family Members. The MSS factors showed good internal reliability (ordinal &agr; > .81) and good convergent validity. Our scale can be suitable for applications in research settings, psychosocial interventions, and, potentially, in clinical practice. Future studies will be conducted to further investigate the properties of the MSS, exploring the association with additional health-related measures (e.g., depressive symptoms and anxiety). L’esperienza dello stigma sessuale (ad esempio, discriminazione e aggressioni fisiche) genera stress da minoranza (minority stress), una forma di stress psicosociale cronico. Lo stress da minoranza ha un effetto negativo sulla salute mentale e fisica dei gay e uomini bisessuali (GUB) ed è una delle cause degli elevati tassi di depressione, ideazioni suicidarie e comportamenti sessuali a rischio di HIV. In ambienti religiosi e conservativi come l’Italia, l’esperienza dello stigma sessuale può essere più frequente e intenso. Nonostante ciò, lo stress da minoranza fra i GUB italiani rimane poco investigato. Lo scopo di questo studio era di esaminare la dimensionalità, l’attendibilità interna, e la validità convergente del Minority Stress Scale (MSS), uno strumento Italiano in grado di misurare le manifestazioni dello stigma sessuale. L’MSS è composto da 50 item che misurano (a) lo Stigma Strutturale, (b) lo Stigma Manifesto, (c) le Aspettative di Essere Discriminato, (d) l’Occultamento dell’Orientamento Sessuale, (e) l’Omofobia Interiorizzata Diretta Verso gli Altri, (f) l’Omofobia Interiorizzata Diretta Verso Se Stessi, e (g) la Consapevolezza dello Stigma. Abbiamo reclutato un campione di 451 GUB Italiani online che hanno compilato l’MSS. La validità convergente è stata valutata utilizzando il Perceived Stress Questionnaire. Attraverso l’analisi fattoriale esplorativa, abbiamo estratto sette fattori teorici e un fattore aggiuntivo composto da 3-item “Aspettative di Discriminazione dai propri Familiari.” I fattori del MSS hanno dimostrato una buona attendibilità interna (ordinal &agr; > .81) e una buona validità convergente. La nostra scala può essere utilizzata nell’ambito della ricerca, interventi psicosociali e, potenzialmente, nella pratica clinica. Ulteriori studi verranno condotti per valutare le proprietà psicometriche dell’MSS come l’associazione con altri fattori legati alla salute (ad esempio, sintomi depressivi e ansia).


PLOS ONE | 2016

Attitudes toward Bisexual Men and Women among a Nationally Representative Probability Sample of Adults in the United States

Brian Dodge; Debby Herbenick; M. Reuel Friedman; Vanessa Schick; Tsung-Chieh (Jane) Fu; Wendy Bostwick; Elizabeth Bartelt; Miguel Muñoz-Laboy; David Pletta; Michael Reece; Theodorus Sandfort


Aids and Behavior | 2015

Gender Expression and Risk of HIV Infection Among Black South African Men Who Have Sex with Men

Theodorus Sandfort; Tim Lane; Curtis Dolezal; Vasu Reddy

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Vasu Reddy

University of Pretoria

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Jessica M. Fogel

Johns Hopkins University School of Medicine

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Tim Lane

University of California

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Xu Guo

Fred Hutchinson Cancer Research Center

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Ying Q. Chen

Fred Hutchinson Cancer Research Center

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