Alfonso Silva-Santisteban - Academia.edu (original) (raw)

Papers by Alfonso Silva-Santisteban

The Lancet Global Health, 2022

Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on ... more Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre-including this research content-immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

Archives of Sexual Behavior, 2022

Sexual and gender politics inform relational expectations surrounding sexual experiences of Peruv... more Sexual and gender politics inform relational expectations surrounding sexual experiences of Peruvian transgender women (TW) and men who have sex with men (MSM). We used the framework of sexual role strain, or incongruence between preferred sexual role and actual sexual practices, to explore potential conflicts between personally articulated identities and externally defined norms of gender and sexuality and its potential to increase HIV/STI risk. Cross-sectional individual- and dyad-level data from 766 TW and MSM in Lima, Peru were used to assess the partnership contexts within which insertive anal intercourse was practiced despite receptive role preference (receptive role strain), and receptive anal intercourse practiced despite insertive role preference (insertive role strain). Sexual role strain for TW was more common with non-primary partners, while for MSM it occurred more frequently in the context of a primary partnership. Receptive role strain was more prevalent for TW with unknown HIV status (reference: without HIV) or pre-sex drug use (reference: no pre-sex drug use). For homosexual MSM, receptive role strain was more prevalent during condomless anal intercourse (reference: condom-protected) and with receptive or versatile partners (reference: insertive). Among heterosexual or bisexual MSM, insertive role strain was more prevalent with insertive or versatile partners (reference: receptive), and less prevalent with casual partners (reference: primary). Our findings suggest TW and MSM experience different vulnerabilities during sexual role negotiation with different partner-types. Future studies should explore the impact of sexual role strain on condom use agency, HIV/STI risk, and discordances between public and private presentations of gender and sexual orientation.

Global Public Health, 2021

In February 2021, the Peruvian 'vaccinegate' scandal broke when the media reported that n... more In February 2021, the Peruvian 'vaccinegate' scandal broke when the media reported that nearly 500 experimental doses of an ongoing COVID-19 trial were given to key individuals not enrolled in the trial. Indeed, vaccine doses were administered to leading politicians, such as the former President and his wife, and other high-level health officials and academic leaders at the universities overseeing ethical compliance and administration of the trial. The 'vaccinegate' scandal in Peru is but one example of how the lack of a coordinated global response to COVID-19 has allowed countries to act in the best interest of some, ultimately, failing to secure a democratic approach to the right to health for all during a global pandemic. While Peruvian vaccinegate is an example of the egregious use of power to further cronyism amid fear and mounting COVID-19 related death, unfortunately, it is not an anomaly. We argue that the sensationalisation of the event has distracted from the existing precarious health system in Peru and the ways in which long-existing abuses of power evident prior to the pandemic limit a just response to it.

Journal of Migration and Health, 2021

Introduction The entangled health and economic crises fueled by COVID-19 have exacerbated the cha... more Introduction The entangled health and economic crises fueled by COVID-19 have exacerbated the challenges facing Venezuelan migrants. There are more than 5.6 million Venezuelan migrants globally and almost 80% reside throughout Latin America. Given the growing number of Venezuelan migrants and COVID-19 vulnerability, this rapid scoping review examined how Venezuelan migrants are considered in Latin American COVID-19 vaccination strategies. Material and Methods We conducted a three-phased rapid scoping review of documents published until June 18, 2021: Peer-reviewed literature search yielded 142 results and 13 articles included in analysis; Gray literature screen resulted in 68 publications for full-text review and 37 were included; and official Ministry of Health policies in Argentina, Brazil, Chile, Colombia, Ecuador, and Peru were reviewed. Guided by Latin American Social Medicine (LASM) approach, our analysis situates national COVID-19 vaccination policies within broader understandings of health and disease as affected by social and political conditions. Results Results revealed a heterogeneous and shifting policy landscape amid the COVID-19 pandemic which strongly juxtaposed calls to action evidenced in literature. Factors limiting COVID-19 vaccine access included: tensions around terminologies; ambiguous national and regional vaccine policies; and pervasive stigmatization of migrants. Conclusions Findings presented underscore the extreme complexity and associated variability of providing access to COVID-19 vaccines for Venezuelan migrants across Latin America. By querying the timely question of how migrants and specifically Venezuelan migrants access vaccinations findings contribute to efforts to both more equitably respond to COVID-19 and prepare for future pandemics in the context of displaced populations. These are intersectional and evolving crises and attention must also be drawn to the magnitude of Venezuelan mass migration and the devastating impact of COVID-19 in the region. Integration of Venezuelan migrants into Latin American vaccination strategies is not only a matter of social justice, but also a pragmatic public health strategy necessary to stop COVID-19.

Journal of the International AIDS Society, 2021

Introduction: Although pre-exposure prophylaxis (PrEP) is a remarkable biomedical advance to prev... more Introduction: Although pre-exposure prophylaxis (PrEP) is a remarkable biomedical advance to prevent HIV, ongoing research on PrEP contributes to and interacts with a legacy of HIV experimentation on marginalized communities in resource-limited settings. This paper explores the complexity of PrEP research mistrust among Peruvian transgender (trans) women who completed a PrEP adherence intervention and those who refused participation (i.e. declined to enrol, voluntarily withdrew, and/or were lost to follow-up). Methods: Data were derived from 86 trans women (mean age 29 years) participants in the formative (four focus groups (n = 32), 20 interviews) and the evaluation stages (34 interviews) of a social network-based PrEP intervention for trans women in Lima, Peru. The formative stage took place from May to July 2015, while the evaluative stage took place from April to May 2018. Audio files were transcribed verbatim and analysed via an immersion crystallization approach using Dedoose (v.6.1.18). Results: Three paradoxes of trans women's participation in PrEP science as a "key" population emerged as amplifying mistrust: (1) increases in PrEP research targeting trans women but limited perceived improvements in HIV outcomes; (2) routine dismissal by research physicians and staff of PrEP-related side effects and the social realities of taking PrEP, resulting in questions about who PrEP research is really for and (3) persistent limitations on PrEP access for trans women despite increasing involvement in clinical trials, fostering feelings of being a "guinea pig" to advance PrEP science. Conclusions: Findings highlight the wisdom inherent in PrEP mistrust as a reflection of trans women's experiences that underscore the broken bonds of trust between communities, researchers and the research enterprise. PrEP mistrust is amplified through perceived paradoxes that suggest to trans women that they are key experimental participants but not target PrEP users outside of research settings. Findings highlight the urgent need to reframe mistrust not as a characteristic of trans women to be addressed through education and outreach, but as a systemic institutional-and industry-level problem replicated, manifested and ultimately to be corrected, through global HIV science.

Journal of the International AIDS Society, 2020

Among men who have sex with men (MSM) and transgender women (TW), stimulant use is high and has b... more Among men who have sex with men (MSM) and transgender women (TW), stimulant use is high and has been associated with an increased risk of HIV infection, suicide and cardiovascular disease (CVD) mortality. We used epidemic modelling to investigate these intersecting health harms among MSM/TW in Lima, Peru and assess whether they could be mitigated by prioritizing HIV pre‐exposure prophylaxis (PrEP) and harm reduction interventions among MSM/TW who use stimulants.

International journal of STD & AIDS, Oct 20, 2016

The HIV epidemic in Peru is concentrated in men who have sex with men and transgender women, who ... more The HIV epidemic in Peru is concentrated in men who have sex with men and transgender women, who have an estimated prevalence > 10%, while the overall population prevalence remains < 1%. Because MSM and TW account for >60% of new infections, it is crucial to understand the full HIV continuum of care for these key populations. We performed a review of the peer-reviewed scientific and grey literature to determine the proportion of HIV-infected MSM and TW in Peru who are diagnosed, linked to and retained in care, taking antiretroviral therapy, and who have attained virologic suppression. Of the estimated 613,080 MSM and TW in Peru in 2015, approximately 63,981 are HIV-infected. Only 24.0% of HIV-infected MSM and TW are aware of their diagnosis, 15.6% are retained in care, 13.6% are on antiretroviral therapy, and 12.0% have achieved adequate virologic control. The largest drop-off in the HIV care continuum occurs at the first step: diagnosis of HIV. Improving HIV serostatus awa...

Global Public Health, 2016

We used qualitative, quantitative and observational methods to assess the feasibility, acceptabil... more We used qualitative, quantitative and observational methods to assess the feasibility, acceptability, and potential efficacy of Proyecto Orgullo (PO), a pilot community mobilisation intervention to decrease sexual risk, promote health-seeking behaviours, and facilitate personal and community empowerment among gay men (GM) and transgender women (TW) in Peru. PO was adapted from Mpowerment and Hermanos de Luna y Sol, two US interventions. PO included six interrelated core elements: 1) Self-reflection Small Group sessions; 2) Supporting peers in HIV prevention; 3) Mobilisation Activities addressing HIV, GM/TW issues, and community empowerment; 4) A Core Group (staff + GM/TW volunteers) designing/implementing those activities; 5) A Project Space; 6) Publicity. PO included specific components for TW, but promoted that GM/TW, who historically have not worked well together, collaborate for a common goal. We found that PO was embraced by GM/TW. PO positively influenced GM/TW's HIV prevention beliefs, self-efficacy, and behaviours; provided social support and created community; facilitated individual and community empowerment; achieved that GM/TW collaborate; and established a functional Community Centre for socializing/conducting mobilisation activities. Community mobilisation strategies, lacking from HIV prevention efforts in Peru but considered key to HIV prevention, can help improve health-seeking behaviours and consolidate social norms supporting preventive behaviours among GM/TW.

AIDS Research and Human Retroviruses, 2014

soap, and helminth treatment could prevent most of these AEs. Contraception (FP) was provided and... more soap, and helminth treatment could prevent most of these AEs. Contraception (FP) was provided and there were no pregancies. In the TasP trial, the majority of participants will have a spouse. Voluntary HIV Testing and Counseling (VTC) is a trial procedure and Couples’ VCT (CVCT) should also be, as recommended by WHO. The protocol refers to ‘family testing’ but this is not a prevention strategy. CVCT is associated with a reduction in new HIV infections and should be explicitly included in protocols and procedures. HIA for TasP should be compared with HIA CVCT, MC, and FP. Conclusions: Both trials and participants would benefit from low-cost screening and treatment services for endemic diseases such as bed nets, routine deworming, soap and chlorine as well as provision of contraceptives. TasP trials should analyze costs and have a rationale for testing interventions with HIA >PPP. Excluding locally affordable HIV prevention services including CVCT from trial SOC is unethical.

JAIDS Journal of Acquired Immune Deficiency Syndromes, 2009

has pursued a mission of combined research, treatment and prevention, in addition to a commitment... more has pursued a mission of combined research, treatment and prevention, in addition to a commitment and sense of compassion towards a broader community that is not limited to the Baltimore region. IHV's work knows no artificially drawn national boundaries. We are active at laboratories and clinics, in the United States and abroad, via teamwork and in partnership with scientists, clinicians, governments, and patients, among others. Our measure of success continues to be an ability to take the results of neverending scientific research directly to the patient and in a manner that allows those advances to have an effective global impact. The Annual International Meeting of IHV has been a centerpiece of our efforts to share with and learn from the broader scientific and clinical communities. The Meeting is one of the world's leading HIV/AIDS conferences, undoubtedly because of the unparalleled quality of presentations and the level of expertise possessed by presenters and participants. It is also because of the vision and dedication of individuals like Hilary Koprowski and Stanley Prusiner who were instrumental in organizing IHV's inaugural meeting. I also want to acknowledge Jeff Meshulam of Profectus BioSciences, Inc., who has contributed so much to so many of our meetings through the years, as well as Beth Peterson, whose tireless efforts now reach fruition. 2008 marks an especially significant year as the anniversary of the finding of the HIV virus, while next year marks the 25th anniversary of the recognition of HIV as the cause of AIDS and the development of the first HIV blood test. These significant milestones give us much reason to reflect upon what we did right, what has gone wrong and where we need to go in the future. Just recently, the field of HIV research suffered a major setback which in my view has too often been minimized. Interim data from a large, expensive vaccine trial, the STEP trial, co-sponsored by the National Institute of Allergy and Infectious Disease (NIAID) and Merck, showed that the vaccine employing an adenovirus vector with HIV genes had failed. Not only did the vaccine offer no protection from HIV, it apparently increased the risk of infection in recipients who had previously been exposed to adenoviruses similar to the vaccine vector. While failures are an unavoidable reality of grand scientific endeavors, the fallout from the STEP trial presents an opportunity to re-evaluate the entire HIV vaccine development process. In celebrating our 11th anniversary, we are honored to present the IHV Lifetime Achievement Award for Scientific Contributions to Dr. Isaac P. Witz of Tel Aviv University. We will also be presenting an unprecedented two IHV Lifetime Achievement Awards for Public Service to The Honorable Robert K. Gray, a Cabinet member in the Eisenhower Administration and former worldwide Chairman of Hill & Knowlton, and Mr. John Evans, co-founder of C-SPAN and an internationally recognized expert in the telecommunications industry. We will also pause to commemorate the life of a good friend, Dr. Bob Ting-a research scientist, entrepreneur and pioneer originating and helping to popularize the term ''biotechnology.'' Bob developed and produced the first FDAapproved diagnostic test kits for HIV antibody confirmation and was the founding president and original chief executive of Profectus Biosciences Inc. I am grateful to all who have chosen to join us this year and am confident that this Meeting will write another important chapter in the book of human retrovirology.

AIDS and Behavior, 2013

For studies using respondent driven sampling (RDS), the current practice of collecting a sample t... more For studies using respondent driven sampling (RDS), the current practice of collecting a sample twice as large as that used in simple random sampling (SRS) (i.e. design effect of 2.00) may not be sufficient. This paper provides empirical evidence of sample-to-sample variability in design effects using data from nine studies in six countries among injecting drug users, female sex workers, men who have sex with men and male-to-female transgender (MTF) persons. We computed the design effect as the variance under RDS divided by the variance under SRS for a broad range of demographic and behavioral variables in each study. We also estimated several measures for each variable in each study that we hypothesized might be related to design effect: the number of waves needed for equilibrium, homophily, and mean network size. Design effects for all studies ranged from 1.20 to 5.90. Mean design effects among all studies ranged from 1.50 to 3.70. A particularly high design effect was found for employment status (design effect of 5.90) of MTF in Peru. This may be explained by a ''bottleneck''-defined as the occurrence of a relatively small number of recruitment ties between two groups in the population. A design effect of two for RDS studies may not be sufficient. Since the mean design effect across all studies was 2.33, an effect slightly above 2.00 may be adequate; however, an effect closer to 3.00 or 4.00 might be more appropriate.

PLOS ONE, 2021

Background The health of transgender men (trans men)–individuals who identify as men and were ass... more Background The health of transgender men (trans men)–individuals who identify as men and were assigned a female sex assigned at birth–is overlooked globally. This mixed-methods exploratory study sought to understand the lived experiences, health, and social needs of trans men in Lima, Peru to bring visibility to specific health needs and inform responsive and holistic public health efforts. Methods Between July 2016-January 2017, 46 trans men in Lima, Peru participated in a mixed-methods study. Four focus group discussions were conducted, complemented with 10 one-on-one interviews to explore in-depth issues that arose in groups. Two individuals participated in both a focus group and an interview. All participants completed a brief survey assessing sociodemographic characteristics and experiences with healthcare, mental health, and stigma. Audio files were transcribed verbatim and analyzed using an immersion crystallization approach to identify themes. Results Participants had a mean...

LGBTQ mental health: International perspectives and experiences., 2020

The Lancet Public Health, 2019

Background HIV incidence remains high among transgender women in Lima, Peru, most of whom report ... more Background HIV incidence remains high among transgender women in Lima, Peru, most of whom report sex work. On the basis of a stakeholder analysis and health system capacity assessment, we designed a mathematical model to guide HIV programmatic planning among transgender women sex workers (TWSW) in Lima. Methods Using a deterministic compartmental model, we modelled HIV transmission among TWSW, their stable partners, and their clients to estimate the impact and cost-effectiveness of combinations of interventions compared with the standard of care on reducing HIV incidence over a 10-year period. We simulated HIV transmission accounting for differences in sexual positioning in anal intercourse and condom use by partner type and fitted the model to HIV surveillance data using Latin hypercube sampling. The interventions we considered were 15% relative increase in condom use with clients and 10% relative increase with stable partners; increase in antiretroviral treatment (ART) coverage at CD4 count lower than 500 cells per mm³ and greater than or equal to 500 cells per mm³; and 15% preexposure prophylaxis (PrEP) coverage using generic and branded formulations. We considered a basic scenario accounting for current limitations in the Peruvian HIV services and an enhanced scenario assuming achievement of the UNAIDS 90-90-90 targets and general improvements in HIV services. The 50 best fits according to log-likelihood were used to give the minimum and maximum values of intervention effect for each combination. We used disability-adjusted life-years (DALYs) to measure the negative health outcomes associated with HIV infection that could be averted through the interventions investigated and calculated incremental cost-effectiveness ratios to compare their cost-effectiveness. Findings Under the basic scenario, combining the four interventions of increasing condom use with clients and stable partners, extending ART to people with CD4 count greater than or equal to 500 cells per mm³, and 15% PrEP coverage with generic drugs would avert 47% (range 27-51) of new infections in TWSW, their clients, and their stable partners over 10 years, with an incremental cost-effectiveness ratio of US$509 per DALY averted. Under the enhanced scenario, this strategy would avert 61% (44-64) of new infections among this population with an incremental cost-effectiveness ratio of 1003perDALYaverted.Underbothscenarios,implementationofthisstrategyapproachesorsurpassesthe501003 per DALY averted. Under both scenarios, implementation of this strategy approaches or surpasses the 50% incidence reduction goal and would represent a cost-effective use of country resources if generic PrEP drugs are used. The total cost of implementing this strategy under the enhanced scenario would be approximately 1003perDALYaverted.Underbothscenarios,implementationofthisstrategyapproachesorsurpassesthe501•2 million per year over 10 years, corresponding to 10% of the current Global Fund's yearly contribution in Peru. Interpretation Investments in HIV services among TWSW in Lima would be cost-effective, even under stringent costeffectiveness criteria when accounting for setting-specific resource constraints. Notable improvements in HIV testing rates, innovative interventions to increase condom use, and reduced PrEP costs will be key to achieving the 50% incidence reduction goal. Modelling studies incorporating stakeholders' perspectives and health system assessments can bring added value to HIV policy making.

PrEP, 2017

Ys for urogenital infection alone. Increased risk of urogenital infection was associated drug use... more Ys for urogenital infection alone. Increased risk of urogenital infection was associated drug use in the past year (aHR=2.44; 95% CI: 1.17-5.08), versatile (compared to insertive) usual sexual positioning (aHR=2.40; 95% CI: 1.01-5.71) or water-based lubricant use compared to no lubricant use (aHR=5.72; 95% CI: 1.28-25.5). Protective factors (p<0.10 each) included increasing age (aHR=0.94), condom use at last sex (aHR=0.53), and increasing social support (aHR=0.73 per quartile increase). Child abuse scores, depressive symptom measures, HIV status, and alcohol use were not associated with incidence. Conclusions NG and/or CT and incidence was high despite baseline testing and treatment, quarterly visits, and peer counselling and support for reducing HIV risk. Partner treatment and program exposure measures will be analysed as data accrual completes with follow-up continuing to September 2017.

Behavioural and Social Science Research, 2017

Methods We conducted 27 semi-structured interviews with purposeful sample of researchers who have... more Methods We conducted 27 semi-structured interviews with purposeful sample of researchers who have developed, implemented or evaluated SBSHI in sSA. Interviews were audio recorded, transcribed verbatim and analysed thematically. Intervention Mapping framework (IM) was used to organise emerging themes. Results Participants are experts in SBSHI in sSA with experiences ranging between 2-30 years. We identified 33 themes that mapped onto the six steps of IM. During development, social factors such as poverty and school infrastructures including quality of teaching, in addition to sexual health needs, should be addressed. SBSHI should be culturally sensitive, address inter-generational and open communications on sexual issues, and clearly state aims to avoid any misunderstanding. Curriculum should also address contemporary issues in HIV prevention (Treatment as Prevention, Pre-exposure Prophylaxis, Voluntary Medical Male Circumcision and Gender-Based Violence). During implementation, SBSHI should be prepared for oppositions at various levels for which we have also identified effective approaches for overcoming them. Due to limited teachers' training in sSA, provisions of simple but detailed facilitators' manual together with supportive supervisions may be critical in ensuring delivery fidelity. During evaluation, computerised audio devices and qualitative interviews with participant observations may facilitate collection and improve validity of adolescents' sexual behaviours data respectively. Conclusion Using insights from experiences of researchers, recommendations for developers, implementers or evaluators of SBSHI in sSA that will complement available guidance are provided.

AIDS and behavior, Jan 18, 2017

Transgender women (TW) represent a vulnerable population at increased risk for HIV infection in P... more Transgender women (TW) represent a vulnerable population at increased risk for HIV infection in Peru. A mixed-methods study with 48 TW and 19 healthcare professionals was conducted between January and February 2015 to explore barriers and facilitators to implementing a model of care that integrates HIV services with gender-affirmative medical care (i.e., hormone therapy) in Lima, Peru. Perceived acceptability of the integrated care model was high among TW and healthcare professionals alike. Barriers included stigma, lack of provider training or Peruvian guidelines regarding optimal TW care, and service delivery obstacles (e.g., legal documents, spatial placement of clinics, hours of operation). The hiring of TW staff was identified as a key facilitator for engagement in health care. Working in partnership with local TW and healthcare provider organizations is critical to overcoming existing barriers to successful implementation of an integrated HIV services and gender-affirmative me...