WORLDWIDE SEXUAL ASSAULT IS a widespread and devastating human rights and public health concern. One particularly vulnerable group is female adolescents.1,2 Among this population, 7% to 48% report that their first sexual experience was forced.3 In the United States, population-based studies reveal that up to 20% of female high school students have experienced forced sex.4–7 These girls were more likely to use tobacco, drugs, and alcohol, feel sad and hopeless, have attempted or considered suicide, have engaged in physical dating violence, be younger at first sex, have had multiple sex partners, and have unprotected sex.5–7 As a result of being assaulted, they are at risk for unplanned pregnancy, genital and extragenital injuries, and sexually transmitted infections, including human immunodeficiency virus (HIV).7–11
There is growing recognition that adolescent sexual assault victims should be counseled on the risk of HIV and assessed for postexposure prophylaxis (PEP).1,12–14 The use of antiretroviral PEP to prevent transmission of HIV subsequent to sexual assault is premised on animal models and clinical findings from the mother-to-child and occupational exposure literatures.15–19 Although the data may not be directly applicable to the nonoccupational exposure situation and the risk of acquiring HIV after a single sexual event, depending on the type of contact, is relatively low (estimated to be from 0.1%–3%), transmission after rape has been documented.12,14,20 Certain characteristics of sexual assault may increase the likelihood of transmission of HIV such as multiple assailants, multiple sex acts, anal penetration, damage to mucous membranes, and the presence and/or occurrence of other sexually transmitted infections.12,14,21 Studies have found that significant numbers of victims are concerned about HIV22–24 and that there is a demand for appropriate preventative antiretroviral therapies.25 In Canada, it has been argued that “patients deserve the choice to try to reduce their chance of HIV transmission after a sexual assault.”26 (p. 642)
To date, there exist only a few small and/or retrospective studies with a particular focus on the use of PEP in adolescents from which to inform strategies on how best to address the needs of this population, particularly in low incidence countries such as Canada.27–31 This is striking given that adolescents can present particular challenges to administering PEP.31 Our goal was to assess the administration and use of PEP among a cohort of at-risk sexually assaulted female adolescents aged 12 to 19 years tracked prospectively. We also wanted to determine factors related to antiretroviral acceptance and completion.
We analyzed data from the HIV PEP Project, an implementation and evaluation of a program of universal offering of antiretroviral medications to sexual assault victims of all ages seen at 18 hospital-based sexual assault treatment centers (SATCs) in Ontario, Canada.32 These centers provide emergency medical care, counseling, and medical forensic examinations to sexual assault victims/survivors across the lifespan and are representative of the province's rural, remote, and urban communities and culturally diverse populations.
The HIV PEP Project received ethics approval from all participating hospitals' Research Ethics Boards as well as from their Medical Advisory and Pharmacy and Therapeutic Committees.
Tools and Training
With the aid of an Advisory Committee of nationally recognized experts in the fields of HIV, pharmacology, and sexual assault, the HIV PEP Project Team developed and distributed to all participating SATCs standardized medical guidelines, counseling tools, client handouts, and data collection forms. To ensure that guidelines, risk assessment protocols, and project procedures were implemented consistently, 6 regional train-the-trainer sessions were delivered by an HIV/infectious disease specialist and/or an experienced sexual assault nurse examiner to 3 core health care providers at each center. These individuals in turn trained the front line staff at their sites.
Each consecutive victim presenting to a SATC between September 10, 2003 and January 31, 2005 was seen by a health care provider. Those presenting within 72 hours of having been sexually assaulted, and who were not HIV-positive, were assessed for their risk of acquiring HIV. For those clients reporting suspected, partial or completed anal, vaginal, or oral penetration, with or without a condom, or an unknown exposure due to, for example, drugging and meeting high risk criteria for HIV (HIV + assailant or assailant at “high risk” for HIV due to intravenous drug use, sex with men, or origins from an endemic country), PEP was strongly recommended. For those meeting “unknown risk” criteria (unknown assailant or known assailant with unknown HIV status), PEP was recommended. Clients in both groups were counseled about their prospective risks and offered antiretroviral medications free-of-cost. The antiretroviral drug regimen prescribed, chosen by local experts based on available data, potency, low pill burden, and tolerability, was Combivir, a combination of zidovudine and lamivudine (GlaxoSmithKline Wellcome, Research Triangle Park, NC), 1 tablet twice a day and Kaletra, a combination of lopinavir and ritonavir (Abbott Laboratories, Abbott Park, IL), 3 capsules twice a day, for 28 days. Clients agreeing to take PEP were given a 5-day starter kit and counseled regarding dosing, side effects, and adherence to the regimen. The medications were dispensed through the hospital-based pharmacies. Before commencing PEP, blood was drawn for complete blood count and tests for renal function, glucose, liver enzyme, creatine kinase, β-HCG, and HIV antibodies. At discharge, each client was given a handout detailing the risk of infection and follow-up care, as well as information about the medications and strategies for managing their side effects. Adolescents who could understand all the information provided, could independently consent to treatment. In cases where a client was intoxicated, care was deferred until informed consent could be secured.
Clients who began the 5-day starter kit were asked to return for follow-up at days 2 to 4 and weeks 2, 3, and 4. A phone call was made at week 1. At each visit, treatment adherence and tolerance was reviewed and they were offered further support and counseling. Grade 1 to grade 3 (mild to severe) PEP-related adverse effects were managed by the health care provider. An HIV/infectious disease expert was consulted for grade 4 (life-threatening) symptoms (grading per National Institute of Allergy and Infectious Diseases/National Institutes of Health [NIAID/NIH]).33 Those continuing with PEP were given the balance of medications over the first 3 follow-up visits. Blood work was repeated at the week-2 visit. Clients were advised to be tested for HIV antibodies at weeks 4 to 6 and months 3, 6, and 12.
At the initial visit, baseline information was collected from each victim. These data included: sociodemographic characteristics (eg, age, gender), assailant characteristics (sex, HIV status), assault characteristics (number of assailants, type of assault), presentation characteristics (eg, anxiety, anogenital trauma), and HIV assessment and care characteristics (eg, risk status, anxiety subsequent to HIV counseling). As well, details regarding the offering and acceptance of PEP (eg, strength of recommendation, reasons declined) were documented.
At follow-up visits, results from blood tests (eg, abnormal values on hemoglobin, urea) and adverse events (eg, grade 1, grade 2, grade 3, or grade 4 toxicity, nausea, vomiting)33 were recorded. Information was also collected on the use of other medications to manage symptoms (eg, dimenhydrinate, acetaminophen), impact on daily activities (eg, unable to work), social supports (eg, family, friends), and the date and reasons for discontinuing PEP (eg, not necessary, side effects).
Data on all females aged 12 to 19 years were analyzed using SAS Version 9.1 (SAS Institute, Cary, NC). Descriptive statistics were used to describe baseline and follow-up data. Proportions were calculated for categorical variables and means with standard deviations (SD) for continuous variables. Variables significant in univariate analyses at a p-value less than 0.20 were entered into logistic regression analyses to determine factors independently associated with PEP acceptance and completion.34 The results are described as odds ratios (OR) with 95% confidence intervals (CI).
Description of the Sample
In total, 397 adolescents aged 12 to 19 years were seen at 1 of 18 SATCs. Of these 386 were female, 325 (84.2%) of whom met the eligibility criteria for PEP. As seen in Table 1, 10.8% were First Nations, 5.5% black, and 4.3% (south)Asian/Pacific Islanders. Most were single (94.5%), living with family (68.0%), and attending school (67.4%). Approximately half were described as intoxicated at the time of examination (49.2%) and had experienced vaginal penetration (53.9%). A third (32.0%) of clients sustained anogenital injuries. Three-fifths (59.7%) were described as moderately-to-highly anxious at the initial visit; for a small minority (10.2%), anxiety increased with HIV counseling. Less than one-quarter (23.4%) of clients were encouraged or strongly encouraged by the examining health care provider to take PEP. The majority (76.9%) of assailants were known to the victim. Only 7.4% met high-risk criteria (9.5% were documented as not high risk and 83.1% as unknown risk).
PEP Eligibility and Acceptance
As seen in Figure 1, those 61 (15.8%) clients who did not meet the eligibility criteria for PEP either experienced no vaginal, anal, or oral penetration (n = 16), or presented more than 72 hours post sexual assault (n = 45). Three hundred and seven (94.5%) clients were offered PEP. Reasons for not offering the medications included that the client was low risk for transmission (eg, doubt as to actual exposure) (n = 8), living in an unstable situation (n = 8), and unconcerned about HIV (n = 3), and had medical concerns such as an illness or was taking contraindicated medications (n = 3). One hundred thirty-one (42.7%) clients accepted PEP. The most common reasons given for declining PEP were a lack of concern about HIV (n = 112), anxiety about side effects and drug interactions (n = 79), and an inability or unwillingness to adhere to the regimen or return for follow-up care (n = 32).
Factors related to PEP acceptance are presented in Table 2. Clients who were students (OR: 2.21; 95% CI: 1.24, 3.91) and moderately-to-highly anxious (OR: 4.60; 95% CI: 2.53, 8.36) were more likely to accept PEP, as were those who were encouraged or strongly encouraged by the examining health care provider to start antiretroviral medications (OR: 5.86; 95% CI: 3.05, 11.25). The relationship between antiretroviral medication acceptance and high risk status for acquiring HIV approached statistical significance (P = 0.0913).
Adherence to Medications
Of the 131 clients who accepted PEP, 97 (74.1%) completed to day 2, 61 (46.6%) completed to day 14, and 44 (33.6%) completed the full 28-day course. Of the 87 who discontinued PEP, less than half (47.1%) gave reasons. These were, most commonly, antiretroviral side effects (n = 30), interference with usual routine (n = 17), inability to take time off work, school or other commitments (n = 8), and belief that the drugs were unnecessary (n = 9).
Factors related to PEP completion are presented in Table 3. Clients who were white (OR: 3.93; 95% CI: 1.17, 13.27) were more likely to complete the full course of PEP, as were those assaulted by an assailant known for less versus more than 24 hours (OR: 5.62; 95% CI: 2.13, 14.84). Status as a student and health care provider encouragement to take PEP approached statistical significance (P = 0.0574 and 0.0611, respectively).
Occurrence of Adverse Events
One hundred (76.3%) clients who accepted PEP attended at least 1 follow-up visit. Among this group, 99 (99.0%) reported experiencing at least 1 side effect from the antiretroviral medication. Seventy-six (76.0%) clients reported events that met the grade 2-to-3, and 1 (1%) the grade 4, criteria. The most common of these symptoms were: nausea (58.0%), fatigue (58.0%), vomiting (22.0%), diarrhea (20.0%), and headache (19.0%). Neither the overall presence nor severity of grade 2-to-4 symptoms was related to PEP completion.
This research is the largest, prospective, multijurisdictional study to date focusing specifically on sexually assaulted adolescents' use of antiretroviral medications to prevent HIV. Three hundred eighty-six females aged 12 to 19 years were seen over an 18 month period at 18 different hospital-based sexual assault treatment centers across the province of Ontario in Canada. Many (68%) had difficulty recalling important details of the assault. No doubt this is in part related to the fact that 24% were asleep or unconscious at the time of the assault and the significant amount of suspected drugging (20%) and voluntary consumption of alcohol (44%) and drugs (12%) in this population. In fact, at the initial visit, 49% of clients were described by the examining health care provider as “intoxicated.” This is in line with previous research on female adolescents and college students which have found that at least 50% experience sexual assault while drinking and/or intoxicated.11,35 Although direct comparisons must be made cautiously, these findings are also similar to some of those of Olshen et al.31 Their retrospective chart review of the use of PEP in sexually assaulted adolescents in Boston found that a substantial proportion of victims were unsure whether they had been vaginally (14%), anally (16%), or orally penetrated (15%), and had “blacked out” (21%) during the assault.
Although 95% of those at risk were offered PEP, fewer than half (43%) initiated the 3-drug regimen. The most common reason documented for declining PEP was a lack of concern about acquiring HIV. Over half (54%) had known their assailant for more than 24 hours, perhaps giving them some confidence in assessing their risk status. Neu et al30 and Olshen et al31 reported much higher acceptance rates (87% and 85%, respectively) in American adolescents. However, their studies also found higher rates of anal/rectal penetration, a particularly high risk exposure, and of assailants who were complete strangers, for whom there could be no HIV risk-related information.
In our study, slightly more than a third (34%) of clients completed the full 28-day course of PEP. Our higher rate of adherence than reported in smaller retrospective studies of adolescents (15% in Olshen et al31 and 20% in Babl et al27) may be related to the fact that clients were tracked prospectively and were provided a rigorous schedule of follow-up that included both emotional and physical support.20 Amongst those who gave reasons, the most common reported for stopping PEP was antiretroviral side effects (73%). More than 3 of 4 (77%) girls who initiated PEP and attended 1 or more follow-up visits experienced moderate-to-severe (grade 2-to-4) symptoms, the most common of which were nausea (58%) and fatigue (58%). The lower rates of adverse events reported in earlier studies are likely because most were retrospective reviews of charts, within which this information may have been inconsistently documented.27,30,31 Nonetheless, subsequent to our research, SATC follow-up nurses were further trained on how better to manage the side effects of PEP use, and a newer formulation of Kaletra, with a lower bill burden, no food restrictions and which may be better tolerated, was introduced.
Several factors were related to PEP acceptance and completion. Clients who were encouraged by a health care provider to take PEP or experienced moderate-to-high anxiety were more likely to accept antiretroviral medication. Students were also more likely to accept PEP, perhaps because they had more social support from family and intimate partners than reported by those not currently attending school. Clients assaulted by men known less than 24 hours, typically street, bar, and party acquaintances or clients of sex workers,36,37 were more likely than those assaulted by assailants known more than 24 hours to complete PEP. Not knowing their assailant could have increased their perception of their risk and their resolve to complete the medications.22 Clients who were white were more likely to complete PEP. This is in contrast to the Olshen et al31 study which found no relationship between being white and PEP completion. However, the Myles et al38 study of female adult sexual assault victims showed lower rates of antiretroviral use among persons of color. In our study, those who were white reported greater familial and intimate partner support, which may have helped them adhere to the drug regimen.
This study has several limitations. First, information was not collected that could have been relevant to PEP acceptance and completion (eg, exact time from assault to offering antiretrovirals). Second, we were able only to follow clients for 1 month and did not have permission to access their results from having been tested for HIV, which was done anonymously. Therefore, HIV seroconversion rates could not be tracked over time and PEP effectiveness in preventing new HIV infections not ascertained. The latter endeavor will require a very large randomized trial of thousands given the generally low risk of HIV transmission in industrialized countries per sexual exposure.29 In the meantime, our large, prospective, observational cohort study sheds light on the feasibility and tolerability of standardized programs of universal offering of PEP for at-risk female adolescent sexual assault victims.
Our study suggests that female adolescent sexual assault victims can pose challenges to administering antiretroviral medications. Many clients did not initiate or complete PEP. They could not recall important details of the assault, did not comply with follow-up, and experienced fairly significant side effects from the medications. Information gleaned from in-depth interviews with adolescents might further shed light on unique barriers to PEP use in this population and inform strategies on how best to counsel, monitor, and support sexually assaulted youth in the clinical setting. Public awareness campaigns should target adolescents who are not enrolled in school as they were less likely, despite their risk of acquiring HIV, than those who were students to accept and complete PEP. At the same time, in clinical settings, better efforts must be made to support sexually assaulted adolescents from culturally diverse backgrounds as they were less likely to finish the course of antiretrovirals and to indicate that they had social supports. As well, because health care provider encouragement to use PEP seem linked to higher acceptance and completion rates, where appropriate, they should be trained to consistently offer and recommend antiretroviral medications to all those meeting established risk criteria. Finally, given so many adolescents were described as intoxicated at the time of examination, it is imperative that sexual assault related educational materials and prevention initiatives continue to address the role of voluntary drug and alcohol consumption in facilitating sexual assault.1,35
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