Sexually transmitted infections, STIs, are a feared sequela of sexual assault.  The most common sexually transmitted infections diagnosed in female survivors of sexual assault are chlamydia, gonorrhea, bacterial vaginosis, and trichomoniasis. [1] Survivors who develop infections are burdened with long term complications such as pelvic inflammatory disease, infertility, and some cancers so prevention is highly desired. Recommendations for appropriate management after a sexual assault have changed several times over the last decade. Treatment for STI after sexual assault varies by country and sometimes within a country depending on local resistance and patterns of infections. The prevalence of certain infections and antibiotic susceptibility continues to change and evolve. New sexually-acquired infections may appear over time, like HIV in the 1980s. New medications that are effective against certain STIs, like HIV, have also been developed in the last half-century. The following information follows current recommendations made by the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO). [1]

Incidence and Prevalence

The transmission of STIs after sexual assault varies widely among populations. They range from high reported rates of 12% for trichomoniasis and 19% for bacterial vaginosis to lower estimates for chlamydia (2%) and gonorrhea (4%). Due to methodological issues, some of these positive cultures may reflect preexisting infections. The literature cannot provide reliable estimate data on the risk for transmission of herpes, hepatitis B, or HIV infection from sexual assault. However, sexual transmission of hepatitis B is common, even in the United States, among non-vaccinated individuals engaging in receptive intercourse with hepatitis B-positive partners, and both hepatitis B and HIV transmission after sexual assault have been reported. [2]

The incidence and prevalence of all sexually transmitted infections in the local area must be considered when determining the most appropriate treatment of a patient. Sexually transmitted infections are common in the United States, particularly in those aged 15-24 years. Human papillomavirus has the greatest incidence and prevalence of any STI in the United States. [3]

Testing

The CDC recommends selective testing for sexually transmitted infections when individuals present for evaluation after sexual assault.  The majority of advanced practitioner sexual assault response team programs in the United States do not routinely perform STI testing on adults and adolescents. STI specimen collection during a sexual assault examination most often does not detect infections transmitted by the perpetrator but merely reflect infections acquired before the assault, and thus, provides no meaningful information for the criminal investigation. Child victims may be an exception if they present with signs or symptoms of an STI. If authorities suspect ongoing child sexual abuse, the discovery of a sexually transmitted infection may provide laboratory proof of the abuse.

For the vast majority of adult and adolescent routine prophylactic antibiotic treatment against Neisseria gonorrhoeae, Chlamydia trachomatis, and incubating syphilis renders testing and discovery of preexisting infections costly as management does not usually differ.[1]

Recommended Treatment

Recommended screening for infectious disease begins with a history and physical. Providers should aim to determine an appropriate treatment while minimizing the possibility of retraumatizing the patient. All decisions are made on a case-by-case basis. Because compliance with follow-up is low, the CDC recommends antibiotics for chlamydia, gonorrhea, and trichomoniasis as well as emergency contraception, hepatitis B, HPV, and HIV evaluation. [4] Patients should also be counseled on symptoms of sexually transmitted infections to help them determine if they require further evaluation at a later time. 

Bacterial Infections

Chlamydia and gonorrhea

Standard recommendations include the treatment of gonorrhea and chlamydia at the time of the initial examination.  Though we use the term "prophylaxis", the antibiotic administration for gonorrhea and chlamydia is more appropriately considered “treatment” that is given so early that the infection has yet to produce clinical symptoms assuming the perpetrator transmitted the bacteria to the victim. 

The suggested evaluation includes NAATs at sites of penetration for C. trachomatis and N. gonorrhoeae.

Currently, the CDC recommends ceftriaxone in a 250 mg dose intramuscularly (IM) as the drug of choice in for preventing active infection of gonorrhea after sexual assault. Ceftriaxone in this dose also effectively prevents incubating syphilis from becoming clinical. For chlamydia prophylaxis, give patients either a 1-gm oral dose of azithromycin or a 7-day course of oral doxycycline (100 mg 2 times a day) or oral tetracycline (500 mg 4 times a day). Since tetracyclines are relatively contraindicated in pregnancy, erythromycin may be used as an alternative. 

Bacterial vaginosis

There is increased suspicion for this condition if the patient presents with malodorous discharge or vaginal itching. The suggested evaluation includes vaginal pH measurement, wet mount, and Whiff test. 

Syphilis

There is no specific recommendation for prophylactic treatment for syphilis, rather a serum sample should be evaluated. Prophylactic treatment for gonorrhea may prevent incubating syphilis from becoming clinical.

Viral Infections

Hepatitis B

The CDC recommends serologic testing for hepatitis B if the victim’s vaccination status is unknown. Examiners in some settings may choose to refer patients for HIV and hepatitis B testing rather than at the time of examination as communicating positive test results and facilitating treatment may be impossible. Testing for hepatitis B is recommended as vaccination, and immune globulin treatment may fail to work, and transmission of the virus from the assault may qualify the victims for lifetime coverage of related medical expenses resulting from the viral transmission by the "victims of the violent crime compensation fund".

Testing may be omitted if the victim is known to be adequately vaccinated with an appropriate antigenic response.

In victims know to be unvaccinated, administer vaccination contemporaneous with an examination or within 24 hours of the assault. Schedule the next to vaccines in this series for 1-2 months and 4-6 months after the first dose for completion of the series.

When a perpetrator is known to be hepatitis B antigen-positive and the victim is known to be unvaccinated and tests hepatitis B antibody negative, the CDC recommends the administration of hepatitis B immune globulin (HBIG) and simultaneous vaccination at a separate site for examinations performed within 14 days of the assault. 

HPV

The CDC recently recommended HPV vaccination for sexual assault survivors generally under the age of 26 who were not previously vaccinated or those who were partially vaccinated.  These include female patients aged 9-26 and in male patients 9-21. MSM patients who were not previously vaccinated or incompletely vaccinated may also receive the HPV vaccine up to the age of 26. The HPV series is three doses. The second vaccine is 1-2 months after the first dose and the third vaccine is 6 months after the first dose. 

Prevention of HIV Infection

There are no published studies on the effectiveness of HIV post-exposure prophylaxis after sexual assault; however, postexposure prophylaxis (PEP) for parenteral occupational exposure to infected body fluids (ex. needlestick) is believed to be effective based on case-control studies.

Although the risk for HIV transmission from one episode of unprotected consensual receptive vaginal intercourse with an infected individual is approximately 1 to 2 in 1000, the violent nature of many sexual assaults and resultant injury may increase the transmission rate. After unprotected receptive anal intercourse, the risk of transmission has been found to be greater at 5 to 32 per 1000.[5]

Almost half of the sexual assault victims express worries about the risk of acquiring HIV after the assault. Examiners must address this concern, provide counseling, and arrange for the option of taking antiretroviral medications (termed post-exposure prophylaxis or PEP) as they may be effective. In the rare case where immediate perpetrator rapid HIV testing can be performed at the same time as the victim’s exam, this information can be used to guide PEP in the same manner used for occupational exposures.  However, this is a highly unlikely scenario. The CDC recommends administering PEP to sexual assault victims within 72 hours of an assault resulting in substantial risk for transmission with a known HIV positive perpetrator.[6] The 28-day medication course for sexual assault victims is similar to that recommended for occupational exposure. As with occupational exposure, PEP should be initiated as soon as possible post-assault. HIV seroconversion due to failures of PEP following sexual exposure has been reported. In cases where the HIV status of the perpetrator is not known, the CDC advises practitioners to decide with patients on an individual case-by-case basis. Some states in the United States legislate medical examiners to offer HIV PEP to all sexual assault victims, and practitioners must be aware of their state laws. The CDC guidelines provide a useful framework to approach individual decisions in prescribing HIV PEP. Assistance with postexposure prophylaxis decisions can be obtained by calling the National HIV Telephone Consultation Service (800-933-3413 or 888-448-4911) or accessing the National HIV/AIDS Clinician's Consultation Center online.[5][7]

Parasitic Infections

Trichomoniasis

Though the CDC recommends routine administration of medication to prevent symptomatic trichomoniasis infection, clinicians may decline to routinely prescribe this treatment due to the significant side effects of the recommended antiprotozoal agents. Examiners may elect to offer prophylaxis for trichomoniasis with a single 2-gm oral dose of metronidazole or tinidazole as recommended by the CDC. Metronidazole often induces nausea, vomiting, and diarrhea which may prevent the absorption of other antibiotic prophylaxis and emergency contraception. If examiners choose to offer this treatment, it is recommended to give the patient the metronidazole to take at home several hours after the other medications have been taken and absorbed.[1]

Summary

CDC Recommendations 2015[1]

• Ceftriaxone 250 mg IM in a single dose PLUS
• Azithromycin 1 gm orally in a single dose 
• Metronidazole 2 gm orally in a single dose (delay by 1 to 2 hours after other medications and assure no concurrent ethanol use) OR tinidazole 2 gm orally in a single dose (delay by 1 to 2 hours after other medications and assure no concurrent ethanol use)
• Pregnancy evaluation and emergency contraception
• Hepatitis B risk evaluation and vaccine with or without HBIG
• HIV risk evaluation and nPEP
• HPV vaccination for appropriate ages

Follow Up and Medication compliance

Follow-up rates in sexual assault survivors have historically been 10-31%. Though the minority of victims complete the recommended follow-up medical care, this should be offered and discussed with the victims verbally and reiterated with explicit written instructions. Most recommend follow-up in 1 to 2 weeks for repeat STI testing if not completely treated during the initial examination, and at 4 to 6 weeks and 3 to 6 months for HIV, hepatitis B, hepatitis C, and syphilis serology testing. [8] When a nurse coordinator was tasked with the responsibility of contacting patients to coordinate a follow-up appointment, the follow-up rates were significantly higher (85%). [9] Factors associated with greater follow-up include young age, alcohol used during the assault, genital trauma, and receipt of prophylactic medications. Factors associated with decreased follow-up include homelessness, intimate partner violence, cocaine use, and psychiatric comorbidity. [4]

Adherence to PEP is lower for victims of sexual assault in comparison to other exposures, highlighting a need for increased attention and guidelines concerning the treatment of sexual assault survivors. [7] This adherence rate is lower for children and adolescent survivors of sexual assault. Factors that increased compliance included health provider and peer encouragement to take PEP, HIV + perpetrator, monetary support for transportation, counseling attendance, and HIV testing/PEP offered at the initial consultation. [10]

Guidelines

Guidelines set forth by the CDC for the evaluation and treatment of sexual assault victims are limited to female and pediatric patients a few of the guidelines being applicable to male victims. [8]  Further, many of the studies regarding post-examination follow-up focus on the factors affecting female survivors. There is limited research focusing on male and LGBT survivors and factors affecting their follow-up.