Sexually Transmitted Infections
Sexually transmitted infections (STIs) are infections passed mainly through sexual contact, caused by bacteria, viruses, or parasites. In the context of adolescent health, this area is distinctive because adolescents and young adults bear a disproportionate share of new infections, often experience asymptomatic disease, and face particular barriers to screening, confidentiality, and care. This reference area orients the reader to the major adolescent-relevant STIs and to the public-health logic of screening, prevention, and management.
Definition
Sexually transmitted infections are infections whose predominant route of transmission is sexual contact (vaginal, anal, or oral); within adolescent health they are studied as a population concentrated in young people, frequently asymptomatic, and shaped by behavioural, developmental, and access-to-care factors.
Scope
This area covers the epidemiology of STIs in adolescents and the rationale for age-based screening; the principal bacterial infections (chlamydia and gonorrhea); human papillomavirus and its link to cervical and other anogenital disease; herpes simplex virus and HIV; and the cross-cutting principles of STI prevention and management. It treats these as a connected reference cluster within adolescent health rather than as clinical instructions for any individual.
Sub-topics
Core questions
- Why are adolescents and young adults at elevated risk of acquiring STIs?
- Which STIs warrant routine screening in sexually active adolescents, and why?
- How do asymptomatic infections shape transmission and the case for screening?
- How do confidentiality and consent considerations affect STI care for minors?
Key concepts
- Asymptomatic infection and silent transmission
- Age-concentrated incidence
- Routine screening of sexually active adolescents
- Confidentiality and consent in adolescent STI care
- Bacterial versus viral STIs
- Reproductive sequelae (e.g., pelvic inflammatory disease, infertility)
- Vaccine-preventable STIs (HPV)
Mechanisms
STIs are acquired through contact with infected mucosal surfaces or fluids during sexual activity. The adolescent burden reflects both biological factors (for example, cervical ectopy that may increase susceptibility to some infections in young women) and behavioural and structural factors such as multiple or concurrent partners, inconsistent condom use, and limited access to confidential services. Because many adolescent infections are asymptomatic, untreated infections persist and propagate through sexual networks, which is the core rationale for routine screening rather than symptom-triggered testing alone.
Clinical relevance
Understanding STIs in adolescents underpins evidence appraisal for screening programmes, vaccination policy, and reproductive-health services. This area describes how infections are distributed, detected, and prevented at a population level; it is educational reference material and is not a substitute for individualized clinical assessment, diagnosis, or treatment.
Epidemiology
Adolescents and young adults account for a large share of newly acquired STIs relative to their proportion of the sexually active population; Satterwhite and colleagues' national estimates illustrate this concentration of incidence and prevalence in younger age groups in the United States. National guidelines correspondingly recommend routine screening of sexually active adolescents for certain infections, reflecting the high background prevalence and the frequency of asymptomatic disease.
History
The systematic study of STIs in adolescents grew out of twentieth-century venereal-disease control and, later, the recognition that chlamydia and other often-silent infections were heavily concentrated in young people. The advent of nucleic acid amplification testing made non-invasive, sensitive screening feasible, and the licensure of HPV vaccines in the mid-2000s reframed part of the field around primary prevention of a cancer-causing STI.
Related topics
Seminal works
- workowski-2021
- satterwhite-2013
- aap-2014-screening
Frequently asked questions
- Why are STIs treated as a distinct area within adolescent health?
- Because adolescents bear a disproportionate burden of new infections, frequently have asymptomatic disease, and face unique confidentiality and access barriers, the screening and prevention logic differs enough from adult care to warrant focused reference coverage.
- Are all STIs in adolescents preventable by vaccine?
- No. Only some, most notably human papillomavirus, are vaccine-preventable; for most STIs prevention relies on behavioural measures, screening, partner management, and treatment.