Backgrounds:

Half of new sexual transmitted infections(STI) occur in adolescents, due to poor sexual education and less awareness of disease, leading to risk behaviours. Our aims were to describe the identified STI and estimate their incidence in patients younger than 18-years attended in our hospital over the last 7 years.

Methods

Retrospective descriptive study, including all STI diagnosed in our tertiary hospital in Madrid between 2015-2021. Two periods were compared: A(2015-2017) and B(2018-2021, excluding 2020 due to COVID-19-lockdown).

Epidemiological-clinical data were collected from medical history. Microbiological tests were performed according to symptoms or medical history and they included: PCR for N.gonorrhoeae(NG) and C.trachomatis(CT) in urethral/urine samples, PCR for herpes-simplex-2(HSV-2) or human papillomavirus(HPV) in scraped samples and serological tests for HIV and syphilis.

Results:

There were 58 STI diagnosed: 33 CT, 20 NG, 2 HSV-2, 2 syphilis(one HIV-infected) and 1 HPV, in 44 adolescents. Median age at diagnosis was 17.0years (IQR16.0-17.6); 25(56%) were female. There were 14 coinfections(CT-NG). CT was isolated more frequently in female(22 vs 11, p:0.02) while NG was in males(12 vs 8, p:0.03).

One third of patients were asymptomatic and diagnosed after reporting sexual risk behaviour. All HSV-2 and HPV were tested due to consistent skin lesions. All infections were treated at the emergency room. Three girls required hospitalization due to pelvic inflammatory disease.

The estimated incidence of STI in patients in period A was 0.51 per 1000-patients-years compared to 0.67 per 1000-patients-years in period B (p:0.36).

Conclusions/Learning Points:

C. trachomatis and N. gonorrhoeae are the main STI diagnosed in adolescents in our setting, but other preventable severe STI occurred. Asymptomatic infections were common as well as co-infections. Paediatricians should be familiar to these infections, which may increase in the following years.