Objectives
Sexually transmissible infections (STIs) represent some of the most prevalent infections globally, with an estimated
375 million new infections with one of the curable STIs each year [1]. About 300 000 new diagnoses of bacterial STIs
are reported annually by the European Union (EU)/European Economic Area (EEA) Member States to The European
Surveillance System, the main source of epidemiological data for the region. Variations in STI surveillance system
characteristics and coverage, together with differences in screening policies and testing practices, hinder the routine
surveillance data from providing an accurate picture of STI epidemiology. To better describe the STI epidemiology, to
adequately inform primary or secondary prevention efforts, and to provide data for monitoring progress towards the
elimination of STIs as a public health threat in Europe requires supplementary epidemiological information, such as
prevalence estimates. This systematic review aimed to identify and collate prevalence estimates for the European
general population and populations of special interest for the four curable STIs: chlamydia (etiological agent Chlamydia
trachomatis), hereinafter CT; gonorrhoea (etiological agent Neisseria gonorrhoeae), hereinafter NG; trichomoniasis
(etiological agent Trichomonas vaginalis), hereinafter TV; and syphilis (etiological agent Treponema pallidum
subspecies pallidum), hereinafter TP.

Methods
This systematic literature review was carried out to retrieve, assess and synthesise all available data on the prevalence
of CT, NG, TV, and TP in European countries (EU/European Free Trade Association (EFTA), United Kingdom (UK) and
EU candidate or potential candidate countries) published between 2012 and 2023 in the general population, suitable
proxy populations, and the following populations of special interest: men who have sex with men (MSM), sex workers,
and people who inject drugs (PWID). The literature search was conducted in a comprehensive set of seven databases
and complemented by grey literature searches. The literature was selected independently by two reviewers, and the
data was extracted by one reviewer and cross-checked by another. The quality of the studies included was assessed
using the Joanna Briggs Institute checklist for prevalence studies. Pooled prevalence estimates were calculated using
random effects models. The review protocol was registered with the International Prospective Register of Systematic
Reviews (PROSPERO) on 23 December 2024: CRD42023492418.

Results
Of the 2 113 unique publications screened, 85 publications reporting on 78 unique studies were included. In addition,
16 studies were included from the previous systematic review commissioned by WHO (Rowley et al., 2019) and four
studies were identified from sources other than the bibliographic databases.
Overall, the current burden of CT in the European region is estimated to be 2.76% (95% CI 1.65–3.87) among women,
and 2.64% (95% CI 0.61–4.67) among men. The prevalence of NG is estimated to be 0.24% (95% CI 0.00–0.50)
among women, and 0.10% (95% CI 0.00–0.22) among men. Prevalence of TV is estimated to be 0.69% (95% CI
0.38–0.99) among women, and 0.00% (95% CI 0.00–0.21) among men. The overall prevalence of TP is estimated to
be 0.14% (95% CI 0.00–0.29) among women in antenatal care, and no estimates are available for men in the general
population. In young people aged 15 to 24 years, the CT prevalence is estimated to be 5.54% in young women and
3.32% in young men. NG prevalence is estimated to be 0.51% in young women and 0.07% in young men. TV
prevalence is estimated to be 0.64% in young women and 0.00% in young men. For TP in young people, only one
study was identified, conducted among young women in antenatal care, reporting a prevalence of 0.00%.
The STI prevalence estimates available in the identified literature are not generalisable to the whole population of
MSM. We calculated pooled estimates for various sub-groups of MSM: In MSM visiting STI clinics, the estimated
prevalences are 9.72% (95% CI 8.27–11.16) for CT, 10.46% (95% CI 6.94–13.97) for NG, 0.10% (95% CI 0.00–0.22)
for TV and 6.53% (95% CI 3.20–9.86) for TP. Among MSM living with HIV, the estimated prevalences are 6.08% (95%
CI 0.75–11.41) for CT, 4.74% (95% CI 0.75–8.72) for NG, 0.94% (95% CI 0.00–2.78) for TV and 14.36% (95% CI
1.10–27.63) for TP. Among MSM on PrEP, the estimated prevalences are 9.57% (95% CI 7.11–12.02) for CT, 8.99%
(95% CI 5.31–12.66) for NG and 6.48% (95% CI 3.95–9.02) for TP. Among MSM engaging in ‘high-risk’ sexual
behaviour, the estimated prevalences are 15.35% (95% CI 9.62–21.08) for CT, 14.37% (95% CI 7.76–20.98) for NG,
1.54% (95% CI 0.00–4.67) for TV and 5.21% (95% CI 1.44–8.98) for TP.
In female sex workers, pooled prevalences are estimated to be 5.50% (95% CI 4.31–6.69) for CT, 2.22% (95% CI 0.63–
3.80) for NG, 8.97% (95% CI 6.03–11.91) for TV, and 1.75% (95% CI 0.04–3.46) for TP. Among male and transgender
(male to female) sex workers, prevalence estimates were found to be particularly high, with pooled prevalences estimated
to be 6.04% for CT, 6.36% (95% CI 0.00–14.25) for NG, and 22.09% (95% CI 5.14–39.03) for TP.
Only two studies were identified for PWID, and both reported on the prevalence of TP. The pooled TP prevalence is
estimated to be 1.56% (95% CI 0.45–2.76), based on the studies from Czechia and Serbia.