Chlamydia Screening Implementation Research Articles

Relation between Chlamydia trachomatis infection and pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility in a Dutch cohort of women previously tested for chlamydia in a chlamydia screening trial

ObjectivesA better understanding of Chlamydia trachomatis infection (chlamydia)–related sequelae can provide a framework for effective chlamydia control strategies. The objective of this study was to estimate risks and risk factors...

The Netherlands Chlamydia cohort study (NECCST) protocol to assess the risk of late complications following Chlamydia trachomatis infection in women

BackgroundChlamydia trachomatis (CT), the most common bacterial sexually transmitted infection (STI) among young women, can result in serious sequelae. Although the course of infection is often asymptomatic, CT may cause pelvic inflammatory disease (PID), leading to severe complications, such as prolonged time to pregnancy, ectopic pregnancy, and tubal factor subfertility. The risk of and risk factors for complications following CT-infection have not been assessed in a long-term prospective cohort study, the preferred design to define infections and complications adequately.MethodsIn the Netherlands Chlamydia Cohort Study (NECCST), a cohort of women of reproductive age with and without a history of CT-infection is followed over a minimum of ten years to investigate (CT-related) reproductive tract complications. This study is a follow-up of the Chlamydia Screening Implementation (CSI) study, executed between 2008 and 2011 in the Netherlands. For NECCST, female CSI participants who consented to be approached for follow-up studies (n = 14,685) are invited, and prospectively followed until 2022. Four data collection moments are foreseen every two consecutive years. Questionnaire data and blood samples for CT-Immunoglobulin G (IgG) measurement are obtained as well as host DNA to determine specific genetic biomarkers related to susceptibility and severity of infection. CT-history will be based on CSI test outcomes, self-reported infections and CT-IgG presence. Information on (time to) pregnancies and the potential long-term complications (i.e. PID, ectopic pregnancy and (tubal factor) subfertility), will be acquired by questionnaires. Reported subfertility will be verified in medical registers. Occurrence of these late complications and prolonged time to pregnancy, as a proxy for reduced fertility due to a previous CT-infection, or other risk factors, will be investigated using longitudinal statistical procedures.DiscussionIn the proposed study, the occurrence of late complications following CT-infection and its risk factors will be assessed. Ultimately, provided reliable risk factors and/or markers can be identified for such late complications. This will contribute to the development of a prognostic tool to estimate the risk of CT-related complications at an early time point, enabling targeted prevention and care towards women at risk for late complications.Trial registrationDutch Trial Register NTR-5597. Retrospectively registered 14 February 2016.

P08.29 Web-tool to assess the cost-effectiveness of chlamydia point-of-care tests at the local level

Introduction Point-of-care tests (POCTs) can eliminate the delay between being tested for chlamydia and receiving the result and treatment, potentially reducing loss to follow-up. However, the cost-effectiveness of POCT implementation depends on multiple factors, including cost-per-test, clinic time, sensitivity and specificity, and the epidemiological impact of POC testing on transmission. Decision-makers consider a complex range of information when determining potential impact of introducing a POCT. To enable commissioners, providers, POCT manufacturers and others to assess the advantages, disadvantages and uncertainty of POCTs for chlamydia in different local settings, we developed a user-friendly web-based tool (POCTiC): www.poctic.uk.net Methods The web-tool is underpinned by a transmission-dynamic model for chlamydia, which uses behavioural and prevalence data from the National Survey of Sexual Attitudes and Lifestyle (Natsal), and reproduces local coverage and diagnosis rates from Public Health England datasets. A user group consisting of industry, sexual health facilitators, sexual health commissioners, clinicians, public health experts, and healthcare consultants, provided input throughout. The model is pre-run, but certain variables (e.g. costs) are user-determined. Results Users can estimate changes in the number of infections and diagnoses occurring under different scenarios, with uncertainty ranges. This allows total costs, and cost per infection averted, to be calculated, while accommodating the considerable variation in chlamydia testing coverage, positivity, and diagnosis rates observed at the local level across England. The epidemiological impact of POC testing is dependent on both test performance characteristics and assumptions about the implementation of the test across local services. Conclusion This tool enables the uncertainties surrounding chlamydia epidemiology and screening implementation to be explored. It also complements local and national knowledge, and contributes to local-level management of chlamydia infection. Users can use the tool to determine the epidemiological impact and cost-effectiveness of implementing POCTs in a particular setting. Disclosure of interest statement This work was funded by Innovate UK. Additional thanks are given to the UK Medical Research Council, the National Institute for Health Research and the Electronic Self-Testing Instruments for Sexually Transmitted Infection (eSTI 2 ) Consortium funded under the UKCRC Translational Infection Research (TIR) Initiative supported by the Medical Research Council (Grant Number G0901608). The funding sources had no involvement in the study design or conduct; the collection, analysis and interpretation of data; the preparation, review or approval of the manuscript; or the decision to submit the manuscript for publication. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, the Department of Health, or Public Health England. CED was employed for part of the project by the National Chlamydia Screening Programme. Atlas Genetics Ltd. develop POCTs for STIs. EHE, CL, STS and CAG have received funding from Atlas Genetics Ltd. for performance evaluations of STI POCTs. The other authors declare no competing interests.

Incidence and persistence of carcinogenic genital human papillomavirus infections in young women with or without Chlamydia trachomatis co-infection.

We assessed whether infection with chlamydia increases the incidence of carcinogenic human papillomavirus (HPV) infections and if HPV persistence is affected by chlamydia co-infection. For 1982 women (16–29 years-old) participating in two consecutive rounds of a chlamydia screening implementation trial, swabs were polymerase chain reaction tested to detect chlamydia and 14 carcinogenic HPV genotypes. HPV type-specific incidence and persistence rates were stratified for chlamydia positivity at follow-up. Associations were assessed by multilevel logistic regression analyses with correction for sexual risk factors. HPV type-specific incidence ranged from 1.4% to 8.9% and persistence from 22.7% to 59.4% after a median follow-up of 11 months (interquartile range: 11–12). Differences in 1-year HPV persistence rates between chlamydia -infected and noninfected women were less distinct than differences in HPV incidence rates (pooled adjusted odds ratios of 1.17 [95% CI: 0.69–1.96] and 1.84 [95% CI: 1.36–2.47], respectively). The effect of chlamydia co-infection on HPV-infection risk did not significantly differ by HPV genotype. In conclusion, infection with chlamydia increases the risk of infection by carcinogenic HPV types and may enhance persistence of some HPV types. Although these findings could reflect residual confounding through unobserved risk factors, our results do give reason to explore more fully the association between chlamydia and HPV type-specific acquisition and persistence.

Chlamydia test results were associated with sexual risk behavior change among participants of the Chlamydia screening implementation in The Netherlands.

To examine the effect of a laboratory-confirmed Chlamydia trachomatis (Ct) test result on subsequent sexual risk behavior in a large population-based screening program. The study population consisted of 16- to 29-year-old participants of the Chlamydia Screening Implementation who completed Ct testing and questionnaires in 2 or more rounds. The influence of a Ct test result on sexual behavior was analyzed by generalized estimating equation models, in which the Ct test result of the previous round was the independent variable and 1 of the 8 sexual risk behavior indicators was the dependent variable, adjusted for covariates. Of 48,910 Chlamydia Screening Implementation participants with completed questionnaires and test results, 14.1% (n = 6802) and 2.6% (n = 1272) completed 2 and 3 rounds, respectively, and were included in this study. Analysis showed that Ct positives less often reported to "never" use condoms with a casual partner (%change pretest/posttest = -5.7% [-10.3 to -0.9]), whereas Ct negatives less often reported to "always" use condoms with a casual partner (-4.6% [-6.4 to -2.8]; odds ratio [95% confidence interval], 1.75 [1.09 to 2.80]). Ct positives also had more sexual partners in the subsequent round than did participants with a Ct-negative test result (relative risk [95% confidence interval], 1.14 [1.01 to 1.29]). Ct test results were associated with subsequent sexual risk behavior. In general, Ct positives were more likely to change their behavior after a Ct test result in a more positive and protective direction than Ct negatives, who were more likely to change their behavior toward more risky behavior. Effects over time after a Ct test should be investigated further, especially in the Ct negatives.

Urogenital Chlamydia trachomatis strain types, defined by high-resolution multilocus sequence typing, in relation to ethnicity and urogenital symptoms among a young screening population in Amsterdam, The Netherlands

IntroductionPrevious studies found conflicting results regarding associations between urogenital Chlamydia trachomatis infections and ethnicity or urogenital symptoms among at-risk populations using either ompA-based genotyping or high-resolution multilocus sequence typing (MLST)....

The added value of chlamydia screening between 2008-2010 in reaching young people in addition to chlamydia testing in regular care; an observational study.

BackgroundInternet-based Chlamydia Screening Implementation (chlamydia screening programme) was introduced in the Netherlands in 2008-2010 to detect and treat asymptomatic infections and to limit ongoing transmission through annual testing and treatment of Chlamydia trachomatis in young people (16-29 years). This population-based screening may be less effective when addressing individuals who are already covered by regular care, instead of addressing a hidden key population without chlamydia testing experience in regular care. This study had two aims: (1) to assess the rate and determinants of newly reached (i.e. not previously tested in 2006-2010) participants in the chlamydia screening programme, and (2) to assess the chlamydia positivity in these newly reached participants.MethodsThis observational matching study included all chlamydia tests performed in subjects aged 16-29 years in eastern South Limburg in the Netherlands (population 16-29 years:41,000) between 2006-2010. Testing was conducted during the systematic chlamydia screening programme (2008-2010), at a sexually transmitted infections clinic (STI clinic), by general practitioners (GPs), and by medical specialists as reported by the medical laboratory serving the region. Data were matched between testing services on individual level. The study population included all participants who were tested at least once for chlamydia by the chlamydia screening programme. Participants were included at their first chlamydia screening participation.ResultsIn the chlamydia screening programme, 80.7% (4298/5323) of participants were newly reached, others were previously tested by the STI clinic (5.7%, n=304), GPs (6.2%, n=328), medical specialists (3.5%, n=187) or a combination of providers (3.9%, n=206). Chlamydia prevalence was similar in newly reached participants (4.8%, 204/4298) and participants previously tested (4.5%, 46/1025, P=0.82). Independent determinants for being a newly reached participant were male gender (men OR 2.9; 95% CI 2.5-3.4) and young age <21 years (versus 25-29 years OR 1.8; 95% CI 1.5-2.2).ConclusionsThe majority of the chlamydia screening programme participants have not been tested by regular care, and show similar chlamydia prevalence as those previously tested. Thereby population-based chlamydia screening adds to the existing regular care by testing young individuals hidden to current regular care.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0612-2) contains supplementary material, which is available to authorized users.

Point-of-care testing versus standard practice for chlamydia: a new approach to assessing the public health effect of rapid testing and treatment at local level

BackgroundChlamydia trachomatis is the most commonly diagnosed bacterial sexually transmitted infection in Britain. Present standards specify treatment within 14 days of testing positive; point-of-care testing (POCT) can eliminate this delay and potentially reduce loss to follow-up; its greater convenience might increase testing. 90-min nucleic acid amplification tests are the best available POCTs for chlamydia, with alternatives under development. However, cost-effectiveness depends on cost-per-test, sensitivity and specificity, and the effect of POCT on transmission. MethodsWe developed a user-friendly web-based method, based on a transmission-dynamic model for chlamydia, to assess the epidemiological impact and cost-effectiveness of introducing POCT in different local settings. The model uses behavioural and prevalence data from the National Survey of Sexual Attitudes and Lifestyles, and Public Health England surveillance data; these data inform on local-level variation, which is represented by sampling parameter values from within their ranges of uncertainty and selecting parameter sets that reproduce local coverage and diagnosis rates. The user can select different local settings, and vary sensitivity and specificity for the tests, specify costs (fixed and unit costs, including staff time), and then assess the effect of introducing POCT in different clinical services by comparison with a situation with no POCT. In the model, presumptive treatment is represented, which we expect to be reduced with the introduction of POCT because test results would be rapidly available to guide treatment. FindingsChanges in numbers of infections and diagnoses occurring under different scenarios (including conventional testing) were estimated, with uncertainty ranges, allowing calculation of total costs, and cost per infection (and serious sequelae) averted, while accommodating the considerable variation in chlamydia testing coverage, positivity, and diagnosis rates. Potential changes in sexual behaviour between test and treatment could determine the relative contribution of increased treatment rates and reduced treatment delay to the reduction in prevalence as a consequence of POCT. InterpretationThe effect of POCT was dependent on both the test performance characteristics and the assumptions about the implementation of the test across local services. Exploration of many uncertainties surrounding chlamydia epidemiology and screening implementation is possible with this model. This method can complement local and national knowledge, and contribute to local-level management of chlamydia infection. FundingInnovate UK (Technology Strategy Board), UK Medical Research Council, and the National Institute for Health Research. The Electronic Self-Testing Instruments for Sexually Transmitted Infection (eSTI2) Consortium eSTI2 is Funded under the UKCRC Translational Infection Research (TIR) Initiative supported by the Medical Research Council (Grant Number G0901608) with contributions to the Grant from the Biotechnology and Biological Sciences Research Council, the National Institute for Health Research on behalf of the Department of Health, the Chief Scientist Office of the Scottish Government Health Directorates, and the Wellcome Trust

P3.332 Matching Participants in a Chlamydia Screening Programme with Patients Seen by STD Clinic, General Practitioner, or Specialist: Added Value of a Chlamydia Screening Programme

BackgroundRegister and internet-based Chlamydia Screening Implementation (CSI) was introduced in the Netherlands to detect and treat asymptomatic infections and to limit ongoing transmission through annual testing and treatment of Chlamydia...

P4.086 CT Test Results Among Participants of the Chlamydia Screening Implementation (CSI) and Its Association with Sexual Behaviour Change

ObjectiveTo assess the association between chlamydia (CT)-test results and subsequent sexual risk behaviour change in a register based Chlamydia Screening (CSI) programme consisting of four screening rounds.MethodsAll participants in the...

P5.038 Development of Prediction Rules For Chlamydia Trachomatis Infection on Population and Individual Level - Potential For Innovative Selective Screening

BackgroundPrediction of Chlamydia trachomatis (Ct) infection is important to identify subjects at high risk. We aimed to develop Ct prediction rules with different levels of detail in information, i.e. with...

Effectiveness of yearly, register based screening for chlamydia in the Netherlands: controlled trial with randomised stepped wedge implementation

Objective To evaluate the effectiveness of register based, yearly chlamydia screening.Design Controlled trial with randomised stepped wedge implementation in three blocks.Setting Three regions of the Netherlands: Amsterdam, Rotterdam, and South...

High yield of reinfections by home-based automatic rescreening of Chlamydia positives in a large-scale register-based screening programme and determinants of repeat infections

IntroductionIn a systematic internet-based Chlamydia Screening Implementation Programme in The Netherlands, all chlamydia-positive participants automatically received a testkit after 6 months to facilitate early detection of repeat infections. The authors...

Who Participates in the Dutch Chlamydia Screening? A Study on Demographic and Behavioral Correlates of Participation and Positivity

In the Netherlands, an Internet-based Chlamydia Screening Implementation was initiated in 3 regions, aiming to reduce population prevalence by annual testing and treatment of people aged 16 to 29 years. We studied who was reached in the first screening round by relating participation and chlamydia positivity to sociodemographic and sexual risk factors. Data from the 2008/2009 screening round were analyzed (261,025 screening invitations, 41,638 participants). Participation rates were adjusted for the sexually active population. Sociodemographic and behavioral correlates of screening participation and positivity were studied by (multilevel) logistic regression models. The overall adjusted participation rate in the first screening round was 19.5% (95% confidence interval, 19.4-19.7) among sexually active people (women, 25%; men, 13%). Sociodemographic factors associated with lower participation were male gender (odds ratio [OR], male 1 vs. female 1.8), young age (OR, 16-19 1 vs. older groups 1.7-2.1), non-Dutch origin (OR between 0.7-0.9), lower education (OR, low 1 vs. high 1.4), high community risk level (0.8), and low socioeconomic status (0.9). Behavioral factors associated with lower participation were a long-standing relationship (0.7) and no reported history or symptoms of sexually transmitted infections (no symptoms, 0.4-0.6) . Factors most strongly related to higher Ct positivity were young age (OR, 1 vs. older groups 0.5-0.8), non-Dutch origin (1.4-2.8), non-Dutch steady partner (1.9-2.7), residence in a high-risk area (1.4-1.5), lower education (high, 0.3-0.5), and a history or symptoms of sexually transmitted infection (no symptoms, 0.4-0.6). Sociodemographic factors associated with lower participation were also associated with higher Ct positivity, showing that high-risk demographic groups are more difficult to mobilize than low-risk groups. Independent of this, higher behavioral risk levels were associated with higher participation rates, suggesting self-selection for screening based on the persons' risk (perception) in both low- and high community risk groups. Our study shows the complexity of the process, including individual and community factors that also interact, when screening for chlamydia.

Comparing two definitions of ethnicity for identifying young persons at risk for chlamydia

Ethnic disparities in chlamydia infections in The Netherlands were assessed, in order to compare two definitions of ethnicity: ethnicity based on country of birth and self-defined ethnicity. Chlamydia positivity in persons aged 16-29 years was investigated using data from the first round of the Chlamydia Screening Implementation (CSI, 2008-2009) and surveillance data from STI centres (2009). Logistic regression modelling showed that being an immigrant was associated with chlamydia positivity in both CSI [adjusted odds ratio (aOR) 2·3, 95% confidence interval (CI) 2·0-2·6] and STI centres (aOR 1·4, 95% CI 1·3-1·5). In both settings, 60% of immigrants defined themselves as Dutch. Despite the difference, classification by self-defined ethnicity resulted in similar associations between (non-Dutch) ethnicity and chlamydia positivity. However, ethnicity based on country of birth explained variation in chlamydia positivity better, and is objective and constant over time and therefore more useful for identifying young persons at higher risk for chlamydia infection.

P1-S4.02 Ethnicity based on the country of birth is better to identify the young population at high risk for Chlamydia infection than self-defined ethnicity

BackgroundChlamydia infections are frequently found in young persons and ethnic minorities. Ethnicity can be defined in different ways. In this study, ethnic disparities in Chlamydia trachomatis positivity in the Netherlands...

O1-S09.04 Modelled impact of changing participation rates on effectiveness of population based chlamydia screening

BackgroundThe Chlamydia Screening Implementation (CSI) is a Dutch large-scale pilot of an internet-based self-sampling Chlamydia trachomatis (Ct) screening program for 16–29-year-old men and women. The effectiveness of CSI can be...

P5-S7.06 Chlamydia screening implementation in the Netherlands is not cost-effective

BackgroundChlamydia trachomatis is the most common sexually transmitted infection in western countries. Most infections are asymptomatic and may cause severe complications. In the Netherlands, 3 years of Chlamydia screening implementation...

P5-S7.04 Who participates in the Dutch chlamydia screening? A study on demographic and behavioural correlates of (repeated) participation and positivity

BackgroundAchieving adequate levels of participation and capturing high risk groups are key stones for the effectiveness of large-scale Chlamydia screening programs. We examined the determinants of (repeated) participation and Chlamydia...

O1-S09.03 Main results and impact analysis of annual Chlamydia screening in a large register-based programme in the Netherlands

BackgroundChlamydia screening programmes can only work when they motivate sufficient persons at risk to get tested regularly. The outcomes of the Chlamydia Screening Implementation (CSI) in the Netherlands are novel...