In the United States, racial and ethnic- and age-related disparities in the intersecting epidemics of sexual violence and HIV are paramount [1-4]. The type of sexual violence most often implicated as a risk factor for HIV acquisition is forced sex, defined as unwanted or nonconsensual penetrative sex that occurs through the use of violence, physical force, or threats thereof [1,5]. Although national statistics highlight equivalent lifetime prevalence rates of forced sex (a form of sexual violence) for Black and White women (21%) and lower rates among Latinx women (14%) [5], multiple US community-based studies have documented a forced sex lifetime prevalence rate as high as 38%-54% for Black women [6-8] and 21%-38% for Latinx women [9-11]. More severe forms of sexual trauma due to forced sex or sexual violence have also been reported among Black and Latinx women [12,13]. Among women who have experienced rape, 40% were raped before the age of 18 years and 79% were raped before the age of 25 years [5]. Specific to HIV infection, women account for 20% of all new HIV infections in the United States, of which 22% occur in adolescent girls and adult women between the ages of 13 and 24 years [14]. Women of color account for most of the incident and prevalent HIV infections and HIV-related deaths among women in the United States [14]. The likelihood of a woman being diagnosed as having HIV in her lifetime is significantly higher for Black (1 in 54) and Latinx (1 in 256) women than for White women (1 in 941) [15].

The sexual- and drug-related behavioral pathways linking sexual violence and HIV susceptibility have been extensively documented [1,2,16]. However, the biological mechanisms driving increased HIV susceptibility following a forced sex incident are understudied, despite documentation of plausible pathways [1,17-19]. A potential pathway is that following trauma due to sexual violence, there is immune dysregulation in the female genital tract (FGT) secretions (ie, cervicovaginal inflammation) that may increase HIV susceptibility (Figure 1) [19-21]. These changes may be due to rough or violent, nonconsensual vaginal or anal intercourse; genital injuries, such as abrasions, tears, and microlesions in the epithelium of the vagina, cervix, or anal regions; sexually transmitted infections (STIs) that cause cell death; mucosal inflammation; and local activation of CD4+ T cells, which may increase the likelihood of HIV transmission [17,19,22]. The production of proinflammatory cytokines as a result of sexual trauma may be disrupted and delay wound repair [18], further compromising the vaginal and anal epithelium [19]. Adolescents may face compounded risk as a result of the immaturity of the FGT and incomplete development of the vaginal, ectocervical, and cervical epithelia [23].

Moreover, as a result of the psychological consequences of intense sexual trauma, individual differences in the effects on the reactivity and regulation of the hypothalamic-pituitary-adrenal (HPA) axis have the potential to affect the innate and adaptive immune system in the FGT [24], further influencing HIV susceptibility (Figure 1) [25-27]. High and variable levels of HPA axis activation also have consequences for the secretion of estrogen and progesterone through effects on the gonadotropin-releasing hormone [28]. The pubertal stage, shifts in emotional lability, increased levels of hormones, and rapid brain development in adolescents render them particularly susceptible to the adverse effects of stress [28].

Sexual trauma may affect the normal stress response (1) immediately via the sexual trauma incident, (2) by the physical and psychological violence that accompanies sexual trauma, and (3) via continued retraumatization and re-experiencing of the sexual trauma after the incident [29,30]. HPA dysregulation has been documented in acute and chronic sexual abuse victims [25,31,32], and it is suggested that alterations in the HPA axis functioning may occur relatively proximate to the traumatic event and correlate with hyperarousal symptoms [26]. Trauma-induced changes in the regulation of the HPA axis may manifest for years after the original trauma or stressor [33]. Chronic and sustained activation of the HPA axis in response to stress can lead to abnormal levels of reproductive hormones, which also has the potential to influence the immune system [17,34]. Specifically, traumatic stress promotes a proinflammatory profile [35], which may increase susceptibility to HIV, either directly by cortisol binding to receptors on immune cells or indirectly by disrupting the regulation of cytokines [18,34].

The pronounced racial and ethnic disparities in sexual violence and HIV highlight the importance of considering potential racial and ethnic group differences in the underlying biological mechanisms. Women of color experience chronic stress because of social and cultural factors (eg, discrimination, medical mistrust, and immigration status) [36,37]. In addition, low socioeconomic status and ethnic minority status are associated with increased psychosocial stress and elevated circulating concentrations of C-reactive protein (CRP), a marker of chronic inflammation, which may indicate preexisting immune dysregulation that could be exacerbated by sexual trauma [37,38]. Furthermore, there are observed differences between Black and White or Latinx women with regard to genes associated with inflammation and antimicrobial immunity [39].

Given the lack of understanding of the biological pathways contributing to the relationship between sexual violence and increased HIV susceptibility, it is critical to explore the potential biological mechanisms at play. This is particularly important given the increased risk of sexual violence and HIV independently among adolescents and women of color, and the possible compounding effect of biology with society and culture.

The primary aim of the THRIVE Study is to assess the impact of sexual trauma on the FGT immunity in adolescent girls and adult women by evaluating (1) the disruption of genital immune biomarkers after sexual trauma and (2) the functional loss of anti-HIV immunity against laboratory-adapted and transmitter/founder (T/F) strains of HIV in genital secretions after sexual trauma. The secondary aim is to assess the impact of sexual trauma on HPA axis dysregulation in adolescent girls and adult women by evaluating (1) correlations between the dysregulated HPA axis and genital immune biomarkers and (2) correlations between the dysregulated HPA axis and functional loss of anti-HIV immunity in genital secretions. Finally, the third aim is to examine whether risk factors linked to sexual trauma, including sexual risk behaviors, substance use, and mental health, influence HPA axis dysregulation and FGT immunity in adolescent girls and adult women after sexual trauma.

The THRIVE (Trauma and HIV Risk: Investigating Stress and the Immune Disruption of the Vaginal Environment) Study is a longitudinal case-control study among girls and women aged 14-45 years, with baseline and 1- and 3-month follow-up study visits. Cases include adolescent girls aged 14-19 years (n=30) and adult women aged 20-45 years (n=30) who have experienced vaginal sexual trauma within the past 15 days. Controls include adolescent girls aged 14-19 years (n=30) and adult women aged 20-45 years (n=30) who have engaged in consensual sex within the past 15 days. The goal is to recruit an ethnically diverse (ie, Black, White, Latinx, and Asian) sample of English- or Spanish-speaking adolescent girls and adult women in each study group.

Inclusion criteria for the THRIVE Study are (1) biologically female; (2) HIV negative at baseline; (3) either aged 14-19 (adolescent girls) or 20-45 (adult women); (4) having experienced forced vaginal penetration by a phallus, perpetrated by a man, within the past 15 days (cases) or having engaged in consensual sex via vaginal penetration within the past 15 days (controls); and (5) ability to provide informed consent (if aged 18 years and older), or ability to provide informed assent (if under the age of 18 years). Exclusion criteria are (1) currently pregnant or breastfeeding, (2) use of douches or other vaginal products within 15 days before baseline, (3) cognitive impairment that would limit participation in study procedures, and (4) for cases, consensual vaginal penetration between the experience of forced vaginal penetration and baseline study visit.

Several precautions are taken with participant data to protect confidentiality. All participants are assigned a numeric personal identification number, which is used as a reference to the participant on all study data to delink the study databases from personal identifying data. Only a few study personnel have access to deidentified project files and databases, and the lowest level of access acceptable for a staff member’s role is only granted after full ethical training and upon the principal investigator’s approval. All study materials on paper containing participant information (eg, contact information sheet and signed consent forms) are stored in a locked cabinet in a locked office, accessible by the project coordinator and principal investigators, and within a building with restricted access.

Quantitative deidentified screening data are downloaded on a weekly basis and distributed graphically and in a tabular format to the project coordinator and principal investigators to monitor recruitment, screening, and enrollment of participants. Deidentified biological samples from blood and vaginal swabs are sent to the laboratories at UCSD for assaying or testing of CRP, progesterone, ACTH, HIV, STIs, yeast infections, and bacterial vaginosis; CVL samples are sent to the George Washington University for assaying of proinflammatory (IL-1α, IL-1β, IL-6, IL-8, and TNF-α) and anti-inflammatory and anti-HIV (SLPI, elafin, β-defensin 2, and MIP3α) soluble immune biomarkers; and saliva specimens are transported to the University of California, Irvine, for assaying of cortisol and DHEA-S. Test results from UCSD are delivered deidentified on paper and directly entered into REDCap, whereas test results from the George Washington University and the University of California Irvine are sent deidentified via email to UCSD and securely stored in the OneDrive THRIVE Study folder. Biological specimens are stored for 6 months to allow for retesting, if necessary, and then disposed of as medical hazard waste.

The THRIVE Study has been approved by the UCSD Human Research Protection Program (HRPP; UCSD HRPP Project #181898). The institutional review boards at the George Washington University and the University of California, Irvine, approved reliance agreements from the institutional review board at UCSD. Before working with the THRIVE Study, all UCSD staff received training in the ethical conduct of human subjects research, compliance, and data management via a collaborative institutional training initiative for biomedical research and Health Insurance Portability and Accountability Act (HIPAA). Women 18 years and older who are interested in participating in the THRIVE Study are asked to sign an informed consent form before participating, whereas adolescent girls younger than 18 years are asked to sign an informed assent form. A waiver of parental assent allows for the protection of privacy for young girls, given the sensitive topic of sexual trauma and sexual intercourse, and is in accordance with the UCSD HRPP’s recommendations. In addition, it is in consonance with the waiver of parental assent implemented for adolescents receiving services at the rape crisis center, a collaborating recruitment site. All participants are asked to sign a HIPAA authorization form. Finally, a certificate of confidentiality for the THRIVE Study is automatically issued by the funding agency, the National Institutes of Health, to protect identifiable research information from forced disclosure (eg, substance use behaviors).

The THRIVE Study uses a data and safety monitoring plan, which is detailed in a standard operating procedures manual as a reference for secure data collection, management, and monitoring procedures for all study staff. Refresher training sessions for staff are scheduled as needed. All data collected for the THRIVE Study are stored on a secure encrypted drive in a locked office within a secure, locked suite in a clinical research building. Participants’ identifying information is stored separately from numeric participant identification numbers. The linkage between identifying information and study data is maintained through Ripple [60], a HIPAA-compliant secure web application designed for the management of identifying information of participants. Ripple is used only for storing identifiable information of participants and not to capture other research data, ensuring the segregation of personally identifiable information and research data. Adverse events (eg, a breach in confidentiality or privacy and risk of serious and unanticipated harm) and serious adverse events (eg, hospitalization or death because of participation in study-related activities) are monitored by study staff. In the case of such an event, study staff make appropriate referrals to care for the participant, including, but not limited to, warm handoffs with the staff licensed therapist and local mental health resources. Immediately after adverse events, the staff is required to report to the principal investigator. The principal investigator reviews the adverse or serious adverse event and incident report and reports the event within 24 hours of its occurrence to the UCSD HRPP.

In addition, a consultant who is a nurse researcher and an international expert in the area of violence against women, with an emphasis on sexual and intimate partner violence and risk or lethality, is available for meetings and debriefing sessions with staff, as needed. Finally, a data and safety monitoring board convenes 2 times per year to review the progress of the THRIVE Study and assesses adherence to the data and safety monitoring plan. This board comprises a practicing infectious disease clinician, a biostatistician specializing in social epidemiology and HIV, and a public health researcher in HIV prevention and treatment. Recommendations are provided to the study team following each meeting.

The goal of the THRIVE Study is to provide knowledge and data to facilitate future hypothesis-driven longitudinal research. As such, the THRIVE Study is an exploratory hypothesis-generating study rather than a hypothesis-testing study. The sample size was determined based on previous studies that have examined the immune microenvironment and wound healing in the female reproductive tract, with total sample sizes ranging between 18 and 77 women [18,40,41]. Given this range, we decided upon a sample size of 30 per case-control group in each age group (adolescent girls and adult women). Furthermore, our power calculation supported this decision. With 30 girls and 30 women in each group, there will be 82% of power to detect a standardized effect size for comparing with any 2 time point means of 0.75 with a two-sample t test and α=.05, 2-sided. As an example of detectable effect size, it is estimated that the standard deviation for SLPI, an anti-inflammatory and anti-HIV biomarker, is 26,000 units [41] so that mean differences of 19,500 and 13,520 units would correspond to a standardized effect size of 0.75 and 0.52, respectively. We expect attrition at the follow-up visits to be between 10% and 15%. However, because the proposed mixed and generalized estimated equations repeated measures approach uses all available data on each participant, these analyses should have very little loss of power because of attrition.

Recruitment of potential participants began in January 2019, and enrollment of participants began in February 2019. Recruitment efforts began with control participants aged 18 years or older as the least sensitive population to be enrolled in the study. This allowed for iterative consideration of study procedures and participant burden and facilitated streamlining and honing of participant experience before enrollment of under 18 years and case populations. Adult case enrollment began in June 2019; however, active recruitment of cases did not begin until September 2019. Case participants enrolled before September 2019 contact the study based on recruitment materials targeting adult control participants. Recruitment of control and case participants under the age of 18 years began in November 2019. As of January 2020, recruitment and enrollment efforts have yielded screening of 557 potential participants and enrollment of 50 participants, including 8 case participants and 42 control participants.

Of the 557 potential participants screened, 60.1% (335/557) had enough information to be classified into a study group: 74.3% (249/335) adult controls, 20.9% (70/335) adolescent controls, 3.3% (11/335) adult cases, and 1.5% (5/335) adolescent cases. Potential participants who screened and indicated a source were recruited through a variety of methods, including social media advertisements (335/468, 71.6%), paper flyers (89/468, 19.0%), referral by friends or family (26/468, 5.6%), and community newspaper advertisements (15/468, 3.2%). It is notable that most participants enrolled to date have been recruited through social media, including 63.1% (157/249) of adult controls, 60% (3/5) of adolescent cases, 64% (7/11) of adult cases, and 80% (56/70) of adolescent cases. With respect to cases, this may allow for access to individuals who may not seek services associated with traditional recruitment locations for recent survivors of sexual violence, such as emergency rooms or rape crisis centers. Of all participants screened, 45.1% (251/557) were classified as eligible, 30.0% (167/557) did not provide enough information to classify their eligibility, 19.0% (106/557) were ineligible, and 1.1% (6/557) declined to complete the screener. Of those eligible, 28.9% (73/253) were contacted and pursued for scheduling. Of those pursued for scheduling, 68% (50/73) were enrolled, 11% (8/73) cancelled before enrollment, and 18% (13/73) declined to enroll. Of the enrolled participants, 6% (3/50) of participants were administratively dropped because of positive STI at baseline. Of participants not administratively dropped or currently progressing through the study, 85% (35/41) have been retained to follow-up 1, and 76% (31/41) have been retained through study completion.

Of the control participants, 62% (26/42) are in the adult group (aged 20-45 years), with a mean age of 27.1 years (SD 7.6). Among adult control participants, 38% (10/26) of participants identify as Black or African American, 31% (8/26) identify as White, and 12% (3/26) as Asian. In addition, 31% (8/26) identify as Hispanic or Latinx (categories are not mutually exclusive). Regarding education, 38% (10/26) of adult control participants have graduated high school or received a General Educational Diploma (GED), 38% (10/26) have completed a bachelor’s or associate’s degree, and 65% (17/26) are current students. More than half of the adult control participants (14/26, 54%) make less than US $10,000 annually, whereas 100% make less than US $49,999 annually.

Of the control participants, 38% (16/42) are in the adolescent group (aged 14-19 years), with a mean age of 18.8 years (SD 0.5). Among adolescent control participants, 6% (1/16) identify as Black or African American, 25% (4/16) identify as White, and 38% (6/16) identify as Asian. In addition, 50% (8/16) identify as Hispanic or Latinx (categories are not mutually exclusive). All adolescent control participants have received a high school diploma or a GED, and 94% (15/16) are current students. Three-quarters of adolescent control participants make less than US $10,000 annually (12/16, 75%), whereas the remainder makes US $19,999 or less annually.

Of the participants, 63% (5/8) are in the adult group (aged 20-45 years), with a mean age of 34.6 years (SD 10.4). Among adult case participants, 80% (4/5) identify as Black or African American and 20% (1/5) as White. In addition, 40% (2/5) identify as Hispanic or Latinx (categories are not mutually exclusive). Regarding education, 60% (3/5) of adult case participants have a high school diploma, GED, or less than a high school diploma, whereas 40% (2/5) have a graduate degree, and 20% (1/5) are current students. Most adult case participants (3/5, 60%) make less than US $29,999 annually, whereas 40% (2/5) make US $50,000 or more.

Of the participants, 38% (3/8) are in the adolescent group (aged 14-19 years), with a mean age of 18.3 years (SD 0.6). Among adolescent case participants, 100% (3/3) identify as White and 33% (1/3) identify as Hispanic or Latinx (categories are not mutually exclusive). One (1/3, 33%) of the adolescent case participants has received a high school diploma or GED, and 2 (2/3, 67%) have completed trade or vocational school; 100% (3/3) are current students. Adolescent case participants make less than US $10,000 (2/3, 67%) or US $50,000 or more (1/3, 33%) annually.