Practice point
Posted: Nov 7, 2019
Upton D Allen, Noni E MacDonald; Canadian Paediatric Society. Updated by Karina A. Top, Infectious Diseases and Immunization Committee
Sexually transmitted infections (STIs) are a growing public health concern in Canada, with rates of Chlamydia trachomatis infection, gonorrhea, and syphilis increasing among adolescents and young adults. This practice point outlines epidemiology, risk factors, laboratory testing, and management for the more common STIs in adolescents, including Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum (syphilis), Trichomonas vaginalis, and herpes simplex virus, with a lesser focus on HIV and human papillomavirus. The need for test-of-cure and indications for further investigations is also discussed. The importance of maximizing opportunities to screen for and treat STIs in this age group is highlighted.
Keywords: Chlamydia trachomatis; Herpes simplex virus; HIV; Human papillomavirus; Neisseria gonorrhoeae; Test-of-cure; Treponema pallidum; Trichomonas vaginalis
Sexually transmitted infections (STIs) are a growing public health concern in Canada, where detection rates for Chlamydia trachomatis infection, syphilis, and gonorrhea in adolescents and young adults have increased over the past decade.[1]
C trachomatis (non-lymphogranuloma venereum serological variants), is the most frequently reported STI in Canada, predominantly affecting women 15 to 24 years of age and men 20 to 29 years of age.[2]
N gonorrhoeae is more prevalent in men 20 to 29 years of age, particularly among men who have sex with men (MSM). Recent data show declining rates among adolescents <20 years of age, but increasing rates in older age groups.[3] The number of female cases is likely to be underestimated because, unlike males, females are often asymptomatic. Concurrent infection with C trachomatis is common.[4] Gonococcal antimicrobial resistance has been growing both in Canada and globally, which makes management with combination antimicrobial therapy and repeat testing post-treatment increasingly necessary.[5]
T pallidum infection (syphilis) most commonly affects MSM 25 to 29 years of age, sex workers and their clients, and individuals who have acquired infection in endemic regions of the world.[6] The incidence of syphilis is rising across Canada among MSM as well as in women with histories of heterosexual contact, and outbreaks have been reported in many Canadian cities. Rates of positive HIV tests vary across Canada. A downward trend in HIV rates in some regions, starting in 2008, was followed by a subsequent rise in new diagnoses from 2014 to 2016.[7] The groups affected most commonly are MSM, individuals who have acquired infection via heterosexual contact, and people who inject drugs (PWID). The largest increases in HIV rates were seen in males, especially 30 to 39 years of age, and among individuals of First Nations ethnicity.[7]
T vaginalis, herpes simplex virus (HSV), and human papillomavirus (HPV) infections are not reportable and the true incidence of these diseases in Canada is not known. Studies have suggested that T vaginalis is the most common STI causing vaginitis, affecting an estimated 2% of sexually active females 14 to 19 years of age in the United States. T vaginalis infections are asymptomatic in greater than 70% of patients.[8]
HSV is the most common cause of genital ulcer disease. Data from the United States (2015-16) estimate the prevalence of HSV-1 at 48% and HSV-2 at 12%. The prevalence of both HSV types is higher among women and increases with age.[9] At present, HSV-1 accounts for more genital infections than HSV-2.
HPV is the most common STI among males and females, with a 75% lifetime risk of infection. Infection with high-risk HPV types (e.g., 16, 18) can lead to cervical and other genital cancers, while low-risk HPV types (e.g., 6, 11) cause anogenital warts (AGWs). The prevalence of high-risk HPV types is higher among females younger than 25 years of age, those of lower socioeconomic status, and among Indigenous women.[10] The introduction of HPV immunization programs for girls has lowered rates of HPV infection, precancerous cervical abnormalities, and AGWs.[11]
During routine and incidental medical visits, health care professionals should be asking young patients open-ended questions to elicit information about sexual history, STIs, and associated risks. Because youth are not frequent users of the health care system, any visit is an opportunity for STI assessment.
Table 1 shows a list of behavioural and other factors associated with increasing risk for STIs.[1][12][13] When exploring risk factors, clinicians should take a simple, confidential, nonjudgmental approach and use language that patients can easily understand.
Table 1. Risk Factors for STIs | |
Any sexually active youth < 25 years old | |
|
|
Adapted from references [1][12][13] |
Comprehensive Canadian guidelines for STI screening are available on the Public Health Agency of Canada website and via a mobile application.[1] The decision to screen is based on risk factors and symptoms, both genital and systemic, always recognizing that rectal and pharyngeal gonococcal infections are often asymptomatic. Test types and specimen requirements should be discussed with the local laboratory before collection (Tables 2 and 3). Ideally, all of a patient’s sexual contacts should be identified, tested, and treated appropriately, although ensuring full disclosure and follow-up in individuals with multiple sexual partners is challenging. Local public health units can assist in this process.
Chlamydia: All sexually active youth younger than 25 years of age should be offered screening at least annually, with more frequent screening offered to individuals with additional STI risk factors (Table 1). After treatment, screening should be repeated every six months if the risk of reinfection persists.[14][15] The nucleic acid amplification test (NAAT) is the most sensitive and specific test for C trachomatis. First-catch void urine, vaginal (including self-collected), endocervical or urethral specimens are all suitable for NAAT testing.[16][17] Evidence suggests that a midstream urine specimen would be adequate, but first catch is preferred.[18] Serological testing should not be used for diagnostic purposes due to cross-reactivity and the associated difficulty of interpreting test results. A noninvasive screening specimen (e.g., urine or a self-collected vaginal swab) can be obtained if the patient is asymptomatic and has no risk factors or indications for a pelvic examination. A culture using cervical or urethral specimens remains the test of choice for medico-legal purposes but is a less sensitive test than NAAT.[19] Confirmation of a positive NAAT by another NAAT using different primers may also be acceptable. Consultation with your local laboratory is advised.[4][20][21]
Test-of-cure (TOC) using NAAT three to four weeks after completion of therapy is recommended in adolescents when compliance is uncertain, an alternative treatment was used, re-exposure is likely, or the adolescent is pregnant.[22]
Gonorrhea: Screening should occur in the same groups as for chlamydial disease. A first-catch urine sample or self-collected vaginal swab is recommended for screening asymptomatic individuals, particularly when urethral and cervical samples are not practical. Pharyngeal specimens should be obtained when there is a history of oral sex, and rectal samples if there is a history of receptive anal intercourse. Cultures provide the best opportunity for determining the resistance pattern of an isolate. Culture with susceptibility testing is particularly important given the emerging antimicrobial resistance of N gonorrhoeae, and should always be performed in the following circumstances, if possible: in sexual assault cases; when treatment failure is presumed; in evaluating pelvic inflammatory disease; in symptomatic MSM; and when infection is believed to have been acquired overseas or in an area of recognized antimicrobial resistance.[1]
As the most sensitive testing method, NATT is often used in place of culture to detect gonorrhea although it does not provide antibiotic susceptibility information. NAAT is validated for urine, vaginal, urethral and cervical samples. NAATs validated for these sites can also detect rectal and oropharyngeal infections, but are currently not licensed in Canada for this purpose. However, clinicians should consult regularly with their regional laboratories because recommendations change over time.
In light of the rising rates of gonococcal resistance to cephalosporins and azithromycin and resulting treatment failures, combination therapy for gonorrhea is recommended. TOC is recommended when the following contexts apply:[22][23] a second-line or alternative treatment is used; antimicrobial resistance is suspected; high re-exposure risk exists; an adolescent is pregnant; a previous treatment has failed; in cases of pharyngeal or disseminated infection; or if signs or symptoms persist following treatment. TOC by culture performed three to seven days post-treatment is preferred. If a culture cannot be obtained, NAAT testing may be performed two to three weeks post-treatment because NAAT remains positive for longer than a culture following adequate therapy.[22]
Repeat screening using NAAT six months after completing therapy is recommended for individuals at risk for reinfection.[24][25] Co-treatment for chlamydia is indicated for all patients with proven gonorrhea, even if chlamydia is not detected.
TABLE 2. What screening tests should be used use to detect sexually transmitted infections? | ||
Infection | Screening tests/samples | Follow-up testing |
Chlamydia |
NAAT is the most sensitive and specific test. Can be performed on urine, urethral swabs, vaginal, or cervical swabs* |
Test-of-cure 3 to 4 weeks after treatment if: – Compliance is uncertain |
Gonorrhea |
NAAT can be used to detect gonorrhea from urine, and from urethral, vaginal, and cervical swabs in symptomatic and asymptomatic individuals* |
Test-of-cure (culture 3 to 7 days post-treatment or NAAT 2 to 3 weeks later) if: – Second-line or alternative treatment was used |
Syphilis |
Serology remains the usual diagnostic test unless the patient has lesions compatible with syphilis |
Follow-up testing depends on the nature of infection, as follows: Primary, secondary, early latent infection: Repeat serology at 1, 3, 6, and 12 months after treatment |
HIV |
Serology is the key diagnostic test. A screening assay is initially performed and, if positive, a Western Blot or other confirmatory test is automatically performed. Screen all patients seeking evaluation and treatment for STIs |
Antibodies may be detected at 3 weeks with fourth-generation HIV antibody screening tests, but can take up to 6 months with older tests. Follow-up testing should be planned when an initial test is negative after a known exposure |
Data adapted from references [1][5][22]. EIA Enzyme immunoassay; MSM Men who have sex with men; NAAT Nucleic acid amplification testing; STIs Sexually transmitted infections *Discuss specimen selection to ensure that the NAAT is validated for the specimen to be collected and the patient being tested, particularly in sexual assault cases. |
Syphilis: All sexually active adolescents should be offered screening for syphilis. Screening in pregnancy should be performed at the first prenatal visit and, ideally, again at delivery. Individuals at high risk for syphilis may also be screened at 28 to 32 weeks’ gestation or at more regular intervals (e.g., monthly) when they are at very high risk (e.g., engaged in sex trade work in an area experiencing an outbreak of infectious syphilis).[20] Non-treponemal tests (such as rapid plasma reagin (RPR)) may yield false-negative results in early cases of primary syphilis. Some laboratories use a “reverse sequence algorithm”, in which a treponemal test is used for screening (e.g., treponemal-specific EIA) with positives confirmed by a nontreponemal test.[24][26] Clinicians should contact their local laboratory for more information.
Follow-up RPR testing is recommended after the treatment of all stages of syphilis with a reactive RPR.[22] Patients diagnosed with syphilis should be referred to an STI or infectious diseases clinic for treatment and follow-up.
HIV: Education about HIV prevention and testing is an essential component of routine health care for adolescents. All sexually active adolescents should be offered screening for HIV. All pregnant adolescents should be screened for HIV at the first prenatal visit. Those considered to be at ongoing risk for HIV should be retested during pregnancy and at the point of delivery.[27] In addition to testing, appropriate counselling should be arranged. Adolescents who are newly diagnosed with HIV require urgent referral to an HIV specialist for initiation of treatment.[28][29] This level of care should continue through the transition into adult care.[30][32]
Routine screening is not recommended for Trichomonas or HSV. Screening for HPV or cervical cancer is not recommended before 21 years of age. Screening for hepatitis A, B, and C may be considered for adolescents with specific risk factors as described in Table 3.
TABLE 3. What samples should be collected based on common clinical syndromes?* | |
Clinical syndrome | Samples/screening tests |
Asymptomatic males with risk factors as per Table 1 |
First-catch urine for Chlamydia trachomatis, Neisseria gonorrhoeae Pharyngeal and/or rectal swabs for C trachomatis, N gonorrhoeae (history of unprotected receptive oral or anal exposure) Serology for: Other serological tests to consider: |
Asymptomatic females with risk factors as per Table 1 |
First-catch urine or Pharyngeal and/or rectal swabs for C trachomatis, N gonorrhoeae (history of unprotected receptive oral or anal exposure) Serology for: Other serological tests to consider: |
Males with symptoms of urethritis |
Urethral swab for Gram stain and culture for gonorrhea (NAAT may also be used, when available) |
Women with symptoms of cervicitis |
Vaginal or cervical swab for Gram stain, N gonorrhoeae (culture or NAAT if culture unavailable) and C trachomatis (NAAT or culture) |
Suspected pharyngeal gonococcal infection |
Swab the posterior pharynx and the tonsillar crypts |
Genital ulcer disease |
Swab of ulcerative, erosive, pustular, or vesicular lesions for HSV culture OR HSV polymerase chain reaction (PCR). Unroof vesicular lesions to collect fluid and place swab in viral transport medium AND Serology for syphilis. If syphilis suspected (e.g., painless ulcer), send swab from ulcer for dark-field examination, direct/indirect fluorescent antibody, or NAAT test if available Referral to an nifectious diseases or STI clinic is recommended for patients with HIV, immunosuppression, systemic symptoms, history of travel (to assess need to test for other pathogens), MSM, atypical, and/or non-healing lesions |
Symptoms of vaginitis |
Collect pooled vaginal secretions, if present If individual is at high risk for STIs as per Table 1, collect vaginal† or cervical swab for N gonorrhoeae culture, and C trachomatis (NAAT or culture) |
Data adapted from reference 1. * For information on clinical syndromes not listed above, consult reference 1. † Vaginal swabs may be self- or clinician-collected. Cervical swabs may be used if a pelvic examination is performed. HSV Herpes simplex virus; NAAT Nucleic acid amplification testing; PWIDs People who inject drugs |
The Canadian Paediatric Society supports treatment protocols set out in the Public Health Agency of Canada’s Canadian guidelines on sexually transmitted infections.[1] Clinicians should always consult this resource and any local public health guidelines for emerging trends and related treatment strategies. Treatment regimens for chlamydia, gonorrhea, HSV, and Trichomonas are summarized in Table 4. Patients diagnosed with syphilis and HIV require urgent specialist referral as described above. The increase in cases of quinolone-resistant gonorrhea [1] and, more recently, a rising number of isolates with reduced susceptibility to cefixime and ceftriaxone, with associated treatment failures, are cause for concern.[5] If recommended treatments are not tolerated, or pathogens are resistant, consultation with infectious disease specialists is recommended.
IM Intramuscular; PO By mouth; STIs Sexually transmitted infections;
Specific primary and secondary prevention strategies are known to decrease the risk for STIs. Clinicians should be mindful of, and counsel on, contextual issues that can impact treatment:
This practice point was initially reviewed by the Adolescent Health and Community Paediatrics Committees of the Canadian Paediatric Society, as well as by the Public Health Agency of Canada’s Canadian STI Guidelines Expert Working Group.
CPS INFECTIOUS DISEASES AND IMMUNIZATION COMMITTEE
Members: Natalie A Bridger MD; Jane C Finlay MD (past member); Susanna Martin MD (Board Representative); Jane C McDonald MD; Heather Onyett MD; Joan L Robinson MD (Chair); Marina I Salvadori MD (past member); Otto G Vanderkooi MD
Liaisons: Upton D Allen MBBS, Canadian Pediatric AIDS Research Group; Michael Brady MD, Committee on Infectious Diseases, American Academy of Pediatrics; Charles PS Hui MD, Committee to Advise on Tropical Medicine and Travel (CATMAT), Public Health Agency of Canada; Nicole Le Saux MD, Immunization Monitoring Program, ACTive (IMPACT); Dorothy L Moore MD, National Advisory Committee on Immunization (NACI); Nancy Scott-Thomas MD, College of Family Physicians of Canada; John S Spika MD, Public Health Agency of Canada
Consultant: Noni E MacDonald MD
Principal authors: Upton D Allen MD, Noni E MacDonald MD
Updated by: Updated by Karina A. Top MD
Disclaimer: The recommendations in this position statement do not indicate an exclusive course of treatment or procedure to be followed. Variations, taking into account individual circumstances, may be appropriate. Internet addresses are current at time of publication.
Last updated: May 27, 2021