Screening for chlamydial infection: an evidence update for the U.S. Preventive Services Task Force

Incident Chlamydia trachomatis Infection in a High School Population

Simple Summary

After a pathogen that causes disease has been introduced in a human population, an understanding of that disease in the population depends on knowing how many people in the population have the disease (prevalence), how fast the disease spreads from one person to another within the population (incidence), and how long the disease remains in an individual once acquired (duration). Infections caused by Chlamydia trachomatis are the most common sexually transmitted bacterial infections in the world. Individuals younger than 25 are the most affected due to the patterns of their sexual activity. In most individuals, these infections do not produce symptoms. Thus, affected individuals usually are not prompted to seek care, and most cases can only be detected through screening. Screenings for chlamydia in United States schools have given an indication of how many adolescents in the population might have chlamydia. In this study, we assessed how quickly chlamydia is acquired within the adolescent population. We determined that 14–19-year-old adolescents are acquiring chlamydia at a pace of 6.6 cases per 100 person-years for boys and 11.9 cases per 100 person-years for girls. Male and female students are acquiring chlamydia within 10 and within 7 months, respectively.

Abstract

Prospective cohort studies of sexually transmitted infections (STIs) are logistically impractical owing to time and expenses. In schools, students are readily available for school-related follow-ups and monitoring. Capitalizing on the logistics that society already commits to ensure regular attendance of adolescents in school, a school-based STI screening in New Orleans made it possible to naturally observe the occurrence of chlamydia and to determine its incidence among 14–19-year-old adolescents. Among participants screened repeatedly, we calculated incidence rates, cumulative incidence, and incidence times. Male (n = 3820) and female (n = 3501) students were observed for 6251 and 5143 person-years, respectively, during which 415 boys and 610 girls acquired chlamydia. Incidence rates per 100 person-years were 6.6 cases for boys and 11.9 cases for girls. In multivariable analysis, the adjusted hazard ratio was 5.34 for boys and 3.68 for girls if the student tested positive for gonorrhea during follow-up, and 2.76 for boys and 1.59 for girls if at first participation the student tested positive for chlamydia, and it increased with age among boys but not among girls. In joinpoint trend analysis, the annual percentage change in the incidence rate was 6.6% for boys (95% CI: −1.2%, 15.1%) and 0.1% for girls (95% CI: −5.3%, 5.7%). Annual cumulative incidence was 5.5% among boys and 8.6% among girls. Median incidence time was 9.7 months for boys and 6.9 months for girls. Our findings can be used to refine assumptions in mathematical modeling and in cost analysis studies of C. trachomatis infection, and provide strong evidence in support of annual chlamydia screening for adolescent boys.

Screening for Chlamydial and Gonococcal Infections: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

The 2014 US Preventive Services Task Force (USPSTF) recommendation statement supported the effectiveness of screening for chlamydia and gonorrhea in asymptomatic, sexually active women 24 years or younger and in older women at increased risk for infection, although evidence for screening in men was insufficient.

OBJECTIVE

To update the 2014 USPSTF review on screening for chlamydial and gonococcal infection in adults and adolescents, including those who are pregnant.

DATA SOURCES

Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Ovid MEDLINE (January 1, 2014, through May 28, 2020) with surveillance through May 21, 2021.

STUDY SELECTION

Randomized clinical trials and observational studies of screening effectiveness, accuracy of risk stratification and alternative screening methods, accuracy of tests, and screening harms.

DATA EXTRACTION AND SYNTHESIS

One investigator abstracted data; a second checked accuracy. Two investigators independently assessed study quality.

MAIN OUTCOMES AND MEASURES

Complications of infection; infection transmission or acquisition; diagnostic accuracy of anatomical site-specific testing and collection methods; screening harms.

RESULTS

Twenty-seven studies were included (N = 179 515). Chlamydia screening compared with no screening was significantly associated with reduced risk of pelvic inflammatory disease (PID) in 2 of 4 trials and with reduced hospital-diagnosed PID (0.24% vs 0.38%); relative risk, 0.6 [95% CI, 0.4-1.0]), but not clinic-diagnosed PID or epididymitis, in the largest trial. In studies of risk prediction instruments in asymptomatic women, age younger than 22 years demonstrated comparable accuracy to extensive criteria. Sensitivity of chlamydial testing was similar at endocervical (89%-100%) and self- and clinician-collected vaginal (90%-100%) sites for women and at meatal (100%), urethral (99%), and rectal (92%) sites for men but lower at pharyngeal sites (69.2%) for men who have sex with men. Sensitivity of gonococcal testing was 89% or greater for all anatomical samples. False-positive and false-negative testing rates were low across anatomical sites and collection methods.

CONCLUSIONS AND RELEVANCE

Screening for chlamydial infection was significantly associated with a lower risk of PID in young women. Risk prediction criteria demonstrated limited accuracy beyond age. Testing for asymptomatic chlamydial and gonococcal infections was highly accurate at most anatomical sites, including urine and self-collected specimens. Effectiveness of screening in men and during pregnancy, optimal screening intervals, and adverse effects of screening require further evaluation.

The Proportion of Young Women Tested for Chlamydia Who Had Urogenital Symptoms in Physician Offices

Using National Ambulatory Medical Care Survey data from 2006 to 2015, we estimated the proportions of young women tested for chlamydia who were symptomatic (urogenital symptoms) or asymptomatic in physician offices. Among women tested for chlamydia, the proportions of women with and without urogenital symptoms were 31.6% and 59.2%, respectively.

Screening for Gonorrhea and Chlamydia in Pregnancy: Room for Improvement

OBJECTIVE

This study sought to determine the proportion of pregnant women who are tested for gonorrhea and chlamydia as part of their prenatal care and to examine patient and provider factors affecting testing rates.

METHODS

The study investigators conducted a retrospective chart review of all patients who delivered at St. Michael's Hospital, an urban tertiary care centre in Toronto, Ontario, between November 2015 and April 2016. Rates of testing and the prevalence of positive test results for gonorrhea and chlamydia were calculated. Chi-square tests were used to compare rates of testing among different types of prenatal care providers (obstetricians, maternal-fetal medicine specialists, family practitioners, midwives) and to determine whether testing rates were affected by patient demographics or characteristics. This study was a Canadian Task Force Classification II-2 retrospective cohort study.

RESULTS

Of the 1315 women who delivered at St. Michael's Hospital during the study period, 1220 met inclusion criteria for the study. Of these women, 186 (15.3%) were not tested for gonorrhea and chlamydia during their pregnancy. There were 11 cases of chlamydia (1.1%) and no cases of gonorrhea. Testing rates were not affected by patient demographic variables or obstetrical history. Midwives and family physicians had the highest testing rates among the provider groups: 93.8% and 91.4%, respectively. Generalist obstetricians tested 88.5% of their patients. Maternal-fetal medicine specialists had a significantly lower rate of testing than the other provider groups, at 64.8% (P < 0.0001).

CONCLUSIONS

Fifteen percent of women were not tested for gonorrhea and chlamydia during the study period even though testing was recommended as part of routine prenatal care. Testing rates varied among providers, and strategies to improve these rates need to be explored.

Sexually Transmitted Infection Review for the Acute Care Pharmacist

PURPOSE

Review selected sexually transmitted infections (STIs) and treatment recommendations for pharmacists and providers practicing in the acute care setting.

SUMMARY

In 2015, the Centers for Disease Control and Prevention (CDC) published an updated guideline on the treatment of STIs with an emphasis on prevention and new diagnostic strategies to combat the growing problem of STIs in the United States. Despite this guidance, the incidence of infection has continued to grow. In October 2016, an in-depth analysis reported that 20 million new infections occur annually in the United States. With this growing burden of disease, it is pertinent that health-care providers optimize their treatment strategies to improve upon the management of STIs. Focusing on identification of asymptomatic- and symptomatic-infected persons, treatment, education, effective follow-up, and counseling for patients and sexual partners, emergency medicine pharmacists and providers can help minimize the negative long-term health consequences of STIs.

CONCLUSION

In the emergency department setting, clinical pharmacists and providers can play a crucial role in preventing and treating STIs and should continue to expand and keep current their knowledge of this topic.

Examining sociodemographic risk factors for Chlamydia trachomatis infection: a population-based cohort study

AIM

Chlamydia trachomatis is the most prevalent bacterial sexually transmitted infection in developed nations and is an important public health concern. We aimed to assess the factors associated with testing and positivity of C. trachomatis in a large population.

METHODS

A retrospective study of a large Canadian health region was undertaken using 2011 census and laboratory data. Demographic and socioeconomic data from the national household survey were linked to microbiologic data for C. trachomatis. Multivariable generalized estimating equation models were constructed to examine relative risk for C. trachomatis testing and positivity.

RESULTS

For testing and positivity, female sex and younger age groups were associated with increased risk. University education and South Asian ethnicity were associated with lower risk of positivity.

CONCLUSION

Incorporating socio-demographic factors will be critical to the success of future sexually transmitted infection public health programs.

Examining Chlamydia trachomatis and Neisseria gonorrhoeae rates between 2010 and 2015: a population-based observational study

Bacterial sexually transmitted infections including Chlamydia trachomatis and Neisseria gonorrhoeae remain an important public health concern. We aimed to assess the population-based incidence of C. trachomatis and N. gonorrhoeae in an age-standardized cohort over time. A retrospective study of a large Canadian health region was undertaken between 2010 and 2015 using linked census and digital laboratory data. C. trachomatis and N. gonorrhoeae tests were linked to patient data. Sex and age-standardized incidence rates (IR) and ratios (IRR) were calculated for cases and testing rates. The annual mean population was 1,150,556 individuals (50.1% female). A total of 15,109 cases of chlamydia and 981 cases of gonorrhoea occurred. The overall IR for chlamydia ranged from 18.81 to 25.63 cases per 10,000 person-years. The IRR was 1.27 (95% CI 1.20-1.34, p < 0.001) for the comparison of 2015 and 2010 rates. For gonorrhoea, overall rates ranged from 0.92 to 1.86 cases per 10,000 person-years. The IRR for gonorrhoea was 2.02 (95% CI 1.56-2.59, p < 0.001) for 2015 and 2010 rates. In our large population-based study spanning six years, we observed increasing rates of C. trachomatis and N. gonorrhoeae with low testing rates.

Screening for genital chlamydia infection

BACKGROUND

Genital infections caused by Chlamydia trachomatis are the most prevalent bacterial sexually transmitted infection worldwide. Screening of sexually active young adults to detect and treat asymptomatic infections might reduce chlamydia transmission and prevent reproductive tract morbidity, particularly pelvic inflammatory disease (PID) in women, which can cause tubal infertility and ectopic pregnancy.

OBJECTIVES

To assess the effects and safety of chlamydia screening versus standard care on chlamydia transmission and infection complications in pregnant and non-pregnant women and in men.

SEARCH METHODS

We searched the Cochrane Sexually Transmitted Infections Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, CINAHL, DARE, PsycINFO and Web of Science electronic databases up to 14 February 2016, together with World Health Organization International Clinical Trials Registry (ICTRP) and ClinicalTrials.gov. We also handsearched conference proceedings, contacted trial authors and reviewed the reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in adult women (non-pregnant and pregnant) and men comparing a chlamydia screening intervention with usual care and reporting on a primary outcome (C. trachomatis prevalence, PID in women, epididymitis in men or incidence of preterm delivery). We included non-randomised controlled clinical trials if there were no RCTs for a primary outcome.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, extracted data and assessed the risk of bias. We resolved disagreements by consensus or adjudication by a third reviewer. We described results in forest plots and conducted meta-analysis where appropriate using a fixed-effect model to estimate risk ratios (RR with 95% confidence intervals, CI) in intervention vs control groups. We conducted a pre-specified sensitivity analysis of the primary outcome, PID incidence, according to the risks of selection and detection bias.

MAIN RESULTS

We included six trials involving 359,078 adult women and men. One trial was at low risk of bias in all six specific domains assessed. Two trials examined the effect of multiple rounds of chlamydia screening on C. trachomatis transmission. A cluster-controlled trial in women and men in the general population in the Netherlands found no change in chlamydia test positivity after three yearly invitations (intervention 4.1% vs control 4.3%, RR 0.96, 95% CI 0.84 to 1.09, 1 trial, 317,304 participants at first screening invitation, low quality evidence). Uptake of the intervention was low (maximum 16%). A cluster-randomised trial in female sex workers in Peru found a reduction in chlamydia prevalence after four years (adjusted RR 0.72, 95% CI 0.54 to 0.98, 1 trial, 4465 participants, low quality evidence).Four RCTs examined the effect of chlamydia screening on PID in women 12 months after a single screening offer. In analysis of four trials according to the intention-to-treat principle, the risk of PID was lower in women in intervention than control groups, with little evidence of between-trial heterogeneity (RR 0.68, 95% CI 0.49 to 0.94, I2 7%, 4 trials, 21,686 participants, moderate quality evidence). In a sensitivity analysis, the estimated effect of chlamydia screening in two RCTs at low risk of detection bias (RR 0.80, 95% CI 0.55 to 1.17) was compatible with no effect and was lower than in two RCTs at high or unclear risk of detection bias (RR 0.42, 95% CI 0.22 to 0.83).The risk of epididymitis in men invited for screening, 12 months after a single screening offer, was 20% lower risk for epididymitis than in those not invited; the confidence interval was wide and compatible with no effect (RR 0.80, 95% CI 0.45 to 1.42, 1 trial, 14,980 participants, very low quality evidence).We found no RCTs of the effects of chlamydia screening in pregnancy and no trials that measured the harms of chlamydia screening.

AUTHORS' CONCLUSIONS

Evidence about the effects of screening on C. trachomatis transmission is of low quality because of directness and risk of bias. There is moderate quality evidence that detection and treatment of chlamydia infection can reduce the risk of PID in women at individual level. There is an absence of RCT evidence about the effects of chlamydia screening in pregnancy.Future RCTs of chlamydia screening interventions should determine the effects of chlamydia screening in pregnancy, of repeated rounds of screening on the incidence of chlamydia-associated PID and chlamydia reinfection in general and high risk populations.

Patient-Delivered Partner Treatment for Chlamydia, Gonorrhea, and Trichomonas Infection Among Pregnant and Postpartum Women in Kenya

BACKGROUND

Patient-delivered partner treatment (PDPT) for sexually transmitted infections (STIs) increases rates of partner treatment and decreases reinfection, but has not been evaluated during pregnancy.

METHODS

This prospective cohort was nested within a larger study of peripartum HIV acquisition. Participants with microbiologic diagnosis of Chlamydia trachomatis, Neisseria gonorrhoeae, and/or Trichomonas vaginalis were screened for participation. Questionnaires were administered to determine PDPT acceptability and barriers. Women were reassessed at least 30 days to determine partner treatment and reinfection. Women whose partners did or did not receive PDPT were compared.

RESULTS

One hundred twelve (22.2%) women in the parent cohort had a treatable STI; 78 within the PDPT study period, of whom 66 were eligible and 59 (89.3%) accepted PDPT. Fifty-one women had PDPT outcome data, 37 (73%) of whom reported partners treated with PDPT. Fourteen women (27%) refused or did not deliver partner treatment. Median age was 22 years (interquartile range, 20-26 years) and 88% were married. Compared with women who delivered PDPT, those who did not were more likely to have a partner living far away (23% vs. 0%, P = 0.004) and to report current intimate partner violence (14% vs. 0%, P = 0.02). Reported PDPT barriers included fear of partner's anger/abuse (5%) and accusations of being STI source (5%).

CONCLUSION

Patient-delivered partner treatment was acceptable and feasible for pregnant/postpartum Kenyan women and may reduce recurrent STIs in pregnancy.

Periodic Presumptive Treatment for Vaginal Infections May Reduce the Incidence of Sexually Transmitted Bacterial Infections

BACKGROUND

Bacterial vaginosis (BV) may increase women's susceptibility to sexually transmitted infections (STIs). In a randomized trial of periodic presumptive treatment (PPT) to reduce vaginal infections, we observed a significant reduction in BV. We further assessed the intervention effect on incident Chlamydia trachomatis, Neisseria gonorrhoeae, and Mycoplasma genitalium infection.

METHODS

Nonpregnant, human immunodeficiency virus-uninfected women from the United States and Kenya received intravaginal metronidazole (750 mg) plus miconazole (200 mg) or placebo for 5 consecutive nights each month for 12 months. Genital fluid specimens were collected every other month. Poisson regression models were used to assess the intervention effect on STI acquisition.

RESULTS

Of 234 women enrolled, 221 had specimens available for analysis. Incidence of any bacterial STI (C. trachomatis, N. gonorrhoeae, or M. genitalium infection) was lower in the intervention arm, compared with the placebo arm (incidence rate ratio [IRR], 0.54; 95% confidence interval [CI], .32-.91). When assessed individually, reductions in STI incidences were similar but not statistically significant (IRRs, 0.50 [95% confidence interval {CI}, .20-1.23] for C. trachomatis infection, 0.56 [95% CI, .19-1.67] for N. gonorrhoeae infection, and 0.66 [95% CI, .38-1.15] for M. genitalium infection).

CONCLUSIONS

In addition to reducing BV, this PPT intervention may also reduce the risk of bacterial STI among women. Because BV is highly prevalent, often persists, and frequently recurs after treatment, interventions that reduce BV over extended periods could play a role in decreasing STI incidence globally.

Comparison of Opt-In Versus Opt-Out Testing for Sexually Transmitted Infections Among Inmates in a County Jail

A majority of jails in the United States rely on an opt-in (voluntary) rather than opt-out (universal) approach to testing for sexually transmitted infections (STIs). This study compares an opt-out approach at intake to opt-in testing during incarceration and estimates the prevalence of common STIs among jail inmates. Data derive from a universal intake pilot testing program (n = 298) and an established, student-led voluntary testing program (n = 1,963), respectively. The adjusted prevalence as well as the odds of testing positive for chlamydia were significantly higher in the opt-out program (p = .025 and .008, respectively) than the opt-in program but not for gonorrhea (p = .402 and .300, respectively). These results demonstrate the potential public health benefit of implementation of universal STI testing of jail inmates.

Estimating chlamydia screening coverage: a comparison of self-report and health care effectiveness data and information set measures

BACKGROUND

Population-based surveys (self-report) and health insurance administrative data (Healthcare Effectiveness Data and Information Set [HEDIS]) are used to estimate chlamydia screening coverage in the United States. Estimates from these methods differ, but few studies have compared these 2 indices in the same population.

METHODS

In 2010, we surveyed a random sample of women aged 18 to 25 years enrolled in a Washington State-managed care organization. Respondents were asked if they were sexually active in last year and if they tested for chlamydia in that time. We linked survey responses to administrative records of chlamydia testing and reproductive/testing services used, which comprise the HEDIS definition of the screened population and the sexually active population, respectively. We compared self-report and HEDIS using 3 outcomes: (1) sexual activity (gold standard = self-report), (2) any chlamydia screening (no gold standard), and (3) within-plan chlamydia screening (gold standard = HEDIS).

RESULTS

Of 954 eligible respondents, 377 (40%) completed the survey and consented to administrative record linkage. Chlamydia screening estimates for HEDIS and self-report were 47% and 53%, respectively. The sensitivity and specificity of HEDIS to define sexually active women were 84.8% (95% confidence interval [CI], 79.6%-89.1%) and 63.5% (95% CI, 52.4%-73.7%), respectively. Forty percent of women had a chlamydia test in their administrative record, but 53% self-reported being tested for chlamydia (κ = 0.35); 19% reported out-of-plan chlamydia testing. The sensitivity of self-reported within-plan chlamydia testing was 71.3% (95% CI, 61.0%-80.1%); the specificity was 80.6% (95% CI, 72.6%-87.2%).

CONCLUSIONS

The Healthcare Effectiveness Data and Information Set does not accurately identify sexually active women and may underestimate chlamydia testing coverage. Self-reported testing may not be an accurate measure of true chlamydial testing coverage.

Age-specific chlamydial infection among pregnant women in the United States: evidence for updated recommendations

BACKGROUND

In the United States, chlamydia screening has been recommended for all pregnant women by the Centers for Disease Control and Prevention (CDC) but only for pregnant women who are at increased risk by the US Preventive Services Task Force (USPSTF). Very limited evidence, such as age-specific chlamydia positivity in pregnant women, has been used to develop these recommendations.

METHODS

We analyzed data from a large commercial laboratory corporation in the United States in 2013. At the first prenatal visit made by women aged 15 to 44 years for whom a chlamydia test was performed between June 2008 and July 2010, we estimated positivity of chlamydia by age, insurance coverage, geographic region, and test type.

RESULTS

Of 601,001 pregnant women aged 15 to 44 years who had routine prenatal care, 62.9% had private insurance and 32.9% had Medicaid coverage, 60.3% resided in the South region, and 43.2% were aged 15 to 24 years, 26.8% were aged 25 to 29 years, and 19.1% were aged 30 to 34 years. Chlamydia positivity was 3.6% overall, and significantly decreased as age increased (15-19 years: 9.6 %; 20-24 years: 5.2%; 25-29 years: 1.8%; 30-34 years: 0.9%; and 35-44 years: 0.6%; P < 0.05).

CONCLUSIONS

Our findings of higher positivity among younger pregnant women suggest that the yield is likely to be greater from screening younger pregnant women than from screening older pregnant women to identify chlamydia infection. The benefits of harmonizing CDC and USPSTF recommendations for pregnant women could be explored by reviewing age-specific positivity data and estimating the frequency of prenatal adverse health outcomes caused by chlamydia to develop consensus regarding the age limit for pregnant women who should be screened.

The Prevalence of Endocervical Chlamydia trachomatis Infection Among Young Females in Kashan, Iran

Background:

Chlamydia trachomatis is one of the major bacterial agents of the sexually transmitted diseases worldwide, especially among young females. There is no data regarding the prevalence of genital Chlamydia infection among young females in Kashan, Iran.

Objectives:

The current study aimed to determine the prevalence of endocervical C. trachomatis infection among females aged 17 - 35 years in Kashan, Iran.

Patients and Methods:

In the current descriptive study, 255 endocervical swab samples were collected from the obstetrics and gynecology clinics of Kashan, Iran from December 2012 to July 2013. Cervical swabs were placed in transport media and sent to the laboratory. To identify C. trachomatis in the samples Polymerase Chain Reaction (PCR) was performed to amplify a sequence in the cryptic plasmid, generating a fragment of about 512base pair. Demographic data was collected considering the relevant risk factors by a standard questionnaire.

Results:

A total of 255 females were tested. The prevalence of genital C. trachomatis was 2.4% (95% confidence interval [CI] 0.54% - 4.26%); 3.2% of the females in the ≤ 25-year-old group were positive versus 1.8% in the 26 - 35-year-old group. The most general presented symptoms of genital C. trachomatis infection were vaginal discharge (66.6%) and lumbar pain (50%). No significant relationships were found between C. trachomatis infection and the risk factors.

Conclusions:

To the authors’ knowledge this is the first study to describe endocervical C. trachomatis infection in this area. The obtained results also emphasized the importance of routine diagnosis of C. trachomatis to control of the infection.

Feasibility of Chlamydia trachomatis screening and treatment in pregnant women in Lima, Peru: a prospective study in two large urban hospitals

OBJECTIVES

Chlamydia trachomatis, which is asymptomatic in most women, causes significant adverse effects for pregnant women and neonates. No programmes conduct antenatal screening in Latin America. We determined chlamydia prevalence, feasibility and acceptability of chlamydia screening, and adherence to treatment in pregnant women in two urban public hospitals in Lima, Peru.

METHODS

We offered chlamydia screening using self-collected vaginal swabs to pregnant women ≥ 16 years of age during their first antenatal visit. Chlamydia-infected women were contacted within 14 days and asked to bring partners for counselling and directly observed therapy with oral azithromycin. Unaccompanied women received counselling, directly observed therapy, and azithromycin to take to partners. Test of cure was performed ≥ 3 weeks after treatment.

RESULTS

We approached 640 women for the study and enrolled 600 (93.8%). Median age was 27.3 years (range 16-47), median lifetime partners 2.3 (range 1-50), and median gestational age 26.1 weeks (range 4-41). Chlamydia prevalence was 10% (95% CI 7.7% to 12.7%). Of 60 infected patients, 59 (98%) were treated with one dose of azithromycin. Fifty-two of 59 (88%) returned for test of cure, all of whom were treated successfully, with 46 (86%) achieving negative test of cure with one dose of azithromycin, and 6 (12%) after retreatment with a second dose.

CONCLUSIONS

C. trachomatis screening and treatment in pregnancy was feasible and highly acceptable in two urban hospitals in Peru. Chlamydia prevalence was high. Clinical trials to evaluate efficacy and cost-effectiveness of chlamydia screening, and treatment of pregnant women to prevent adverse pregnancy outcomes in low-resource settings, are warranted.

Genital chlamydia prevalence in Europe and non-European high income countries: systematic review and meta-analysis

Background

Accurate information about the prevalence of Chlamydia trachomatis is needed to assess national prevention and control measures.

Methods

We systematically reviewed population-based cross-sectional studies that estimated chlamydia prevalence in European Union/European Economic Area (EU/EEA) Member States and non-European high income countries from January 1990 to August 2012. We examined results in forest plots, explored heterogeneity using the I² statistic, and conducted random effects meta-analysis if appropriate. Meta-regression was used to examine the relationship between study characteristics and chlamydia prevalence estimates.

Results

We included 25 population-based studies from 11 EU/EEA countries and 14 studies from five other high income countries. Four EU/EEA Member States reported on nationally representative surveys of sexually experienced adults aged 18–26 years (response rates 52–71%). In women, chlamydia point prevalence estimates ranged from 3.0–5.3%; the pooled average of these estimates was 3.6% (95% CI 2.4, 4.8, I² 0%). In men, estimates ranged from 2.4–7.3% (pooled average 3.5%; 95% CI 1.9, 5.2, I² 27%). Estimates in EU/EEA Member States were statistically consistent with those in other high income countries (I² 0% for women, 6% for men). There was statistical evidence of an association between survey response rate and estimated chlamydia prevalence; estimates were higher in surveys with lower response rates, (p = 0.003 in women, 0.018 in men).

Conclusions

Population-based surveys that estimate chlamydia prevalence are at risk of participation bias owing to low response rates. Estimates obtained in nationally representative samples of the general population of EU/EEA Member States are similar to estimates from other high income countries.

Recent advances in understanding and managing Chlamydia trachomatis infections

Worldwide, Chlamydia trachomatis infections rank among the most common sexually transmitted infections (STI), and cause notable reproductive morbidity in women. Although advances in highly accurate and non-invasive diagnostic testing have allowed for better estimation of the burden of disease—especially the asymptomatic state—we still lack a true point-of-care test, and many infections go undetected and untreated. Moreover, limited resources and effort for managing sexual partners of those in whom infection is actually identified comprise a major challenge to control. Here, we review the current state of understanding of this common infection, and efforts to control it.

Comparing Resident Self-Report to Chart Audits for Quality Improvement Projects: Accurate Reflection or Cherry-Picking?

BACKGROUND

Resident engagement in quality improvement is a requirement for graduate medical education, but the optimal means of instruction and evaluation of resident progress remain unknown.

OBJECTIVE

To determine the accuracy of self-reported chart audits in measuring resident adherence to primary care clinical practice guidelines.

METHODS

During the 2010-2011 academic year, second- and third-year internal medicine residents at a single, university hospital-based program performed chart audits on 10 patients from their primary care clinic to determine adherence to 16 US Preventive Services Task Force primary care guidelines. We compared residents' responses to independent audits of randomly selected patient charts by a single external reviewer.

RESULTS

Self-reported data were collected by 18 second-year and 15 third-year residents for 330 patients. Independently, 70 patient charts were randomly selected for review by an external auditor. Overall guideline compliance was significantly higher on self-reported audits compared to external audits (82% versus 68%, P < .001). Of 16 guidelines, external audits found significantly lower rates of adherence for 5 (tetanus vaccination, osteoporosis screening, colon cancer screening, cholesterol screening, and obesity screening). Chlamydia screening was more common in audited charts than in self-reported data. Although third-year residents self-reported higher guideline adherence than second-year residents (86% versus 78%, P < .001), external audits for third-year residents found lower overall adherence (64% versus 72%, P  =  .040).

CONCLUSIONS

Residents' self-reported chart audits may significantly overestimate guideline adherence. Increased supervision and independent review appear necessary to accurately evaluate resident performance.

[Vaginal discharge in pregnant women: comparison between syndromic approach and examination of clinical nursing practice]

This is a study for assessment of a quantitative approach in pregnant women (N=104), in which findings of vaginal infection were compared. The findings were obtained by two means, flowchart of vaginal discharge, and typical examinations in the clinical nursing practice. Data were collected from January to July 2011 through interviews and gynecological examinations. The flowchart showed no efficacy to identify candidiasis and trichomoniasis. Furthermore, it showed low sensitivity (0.0%; 50%) and positive predictive value (0.0%; 3.6%) for both infections, and low specificity for trichomoniasis (46%). The flowchart was shown to be satisfactory for bacterial vaginosis, with high sensitivity (100%), negative predictive value (100%), and accuracy (74%). We conclude that use of the flowchart should be reassessed, as it was not able to identify important infections in pregnant women. A continuous effort must be directed for development of effective tests in order to prevent the spread of infection and reduce the number of unnecessary treatments.

Variations in measurement of sexual activity based on EHR definitions

OBJECTIVE

The goal of this study was to compare the performance of 4 operational definitions of sexual activity by using data electronically abstracted from electronic health records (EHRs) and examine how documentation of Chlamydia screening and positivity vary according to definition of sexual activity.

METHODS

Extracts were created from EHRs of adolescent females 12 to 19 years old who had ≥1 visit to a primary care practice during 2011 at 4 US pediatric health care organizations. We created 4 definitions of sexual activity derived from electronically abstracted indicator variables. Percent sexually active, documentation of Chlamydia screening, and rate of positive Chlamydia test results per 1000 adolescent females according to the sexual activity definition were calculated.

RESULTS

The most commonly documented individual indicator of sexual activity was "patient report of being sexually active" (mean across 4 sites: 19.2%). The percentage of adolescent females classified as sexually active varied by site and increased as more indicator variables were included. As the definition of sexual activity expanded, the percentage of sexually active females who received at least 1 Chlamydia test decreased. Using a broader definition of sexual activity resulted in improved identification of adolescent females with Chlamydia infection. For each sexual activity definition and performance item, the difference was statistically significant (P < .0001).

CONCLUSIONS

Information about sexual activity may be gathered from a variety of data sources, and changing the configurations of these indicators results in differences in the percentage of adolescent females classified as sexually active, screened for Chlamydia infection, and Chlamydia infection rates.

Testing and treatment for sexually transmitted infections in adolescents--what's new?

BACKGROUND

Significant changes are taking place in the diagnosis and management of sexually transmitted infections (STI) in adolescents and young adults.

FINDINGS

In this review article, we provide an update of STIs in adolescents and young adults including: (1) Adolescent risk; (2) Screening guidelines; (3) Clinical manifestations; (4) Diagnostic testing; (5) Treatment; and (6) Prevention; with an emphasis on "what's new" in the field.

CONCLUSIONS/SIGNIFICANCE

While the impacts of STI epidemiology and health care access are leading to new recommendations for screening and prevention, changes in technology and drug resistance are promoting new methods of STI testing and ongoing revisions of STI treatment recommendations.

Field evaluation of the CRT and ACON chlamydia point-of-care tests in a tropical, low-resource setting

OBJECTIVE

To evaluate the clinical performance of two chlamydia point-of-care (POC) tests compared with a gold standard nucleic acid amplification testing (NAAT).

METHODS

Tests evaluated were the Chlamydia Rapid Test (CRT), Diagnostics for the Real World and the ACON Chlamydia Rapid Test Device, ACON Laboratories (ACON). Overall 226 men and 225 women in Port Vila, Vanuatu, participated in this prospective study in 2010. NAAT and POC testing was performed on samples of male urine and female vaginal swabs for 156 men and 223 women (CRT), and 133 men and 75 women (ACON).

RESULTS

The sensitivity and specificity of the CRT in men were 41.4% (95% CI 23.5% to 61.1%) and 89.0% (95% CI 82.2% to 93.8%), respectively, and in women 74.2% (95% CI 61.5% to 84.5%) and 95.7% (95% CI 91.3% to 98.2%), respectively; for ACON, they were 43.8% (95% CI 19.8% to 70.1%) and 98.3% (95% CI 93.9% to 99.8%) in men, and in women 66.7% (95% CI 22.3% to 95.7%) and 91.3% (95% CI 82.0% to 96.7%), respectively. Both tests were (absolutely) insensitive at organism loads less than 1000 (log=3) per mL or per swab; the CRT sensitivity was significantly lower at loads less than, compared with those greater than, 100 000 (log=5) per mL or per swab.

CONCLUSIONS

The performance of both CRT and ACON is well below the levels stated by the manufacturers. The evaluated tests are unlikely to be helpful in clinical settings due to the high proportion of false-negatives that will go untreated and false-positives that will result in overtreatment and potential adverse social consequences.

Screening and management of genital chlamydial infections

Chlamydial genital infection is common and asymptomatic in most cases. National screening efforts developed to educate practitioners, expand screening, and link testing to local health laboratories are not meeting the needs of populations at great risk of disease, including young racial/ethnic minority women and sexual minorities. The development and availability of newer diagnostics will likely make chlamydia testing more efficient and widely available for patients and providers. Practitioners are reminded to have a low threshold to offer testing and presumptive treatment to patients that are deemed at high risk of disease, particularly those who are challenging to engage in care.

Chlamydia screening coverage estimates derived using healthcare effectiveness data and information system procedures and indirect estimation vary substantially

BACKGROUND

Screening coverage is an important determinant of chlamydial control program success.

OBJECTIVES

The aim of this study was to compare chlamydial screening coverage estimates.

METHODS

We compared 9 estimates among women aged 15 to 25 years in Washington State, 2009. Four used Healthcare Effectiveness Data and Information System (HEDIS) procedures among Group Health enrollees. Separate HEDIS estimates assessed all enrollees and the subset of women who used services; for each group, separate estimates defined the sexually active population using HEDIS methods or National Survey of Family Growth (NSFG) data. Three indirect screening estimates used census and NSFG data to define the population's size and derived the number of tests performed by dividing the number of reported cases by test positivity defined using data from different laboratories, adjusted for repeat testing. A fourth indirect estimate was adjusted for reason for testing. A direct-indirect estimate combined data on the number of tests performed in reporting laboratories and an indirect estimate of tests performed elsewhere.

RESULTS

Healthcare Effectiveness Data and Information System procedures and NSFG data yielded similar estimates of the percentage of women who were sexually active (60% vs. 61%). Screening coverage estimated by HEDIS was higher among Group Health users (43.6%) than among all enrollees (34.2%). Indirect screening coverage estimates varied from 46.4% to 68.7%. The direct-indirect estimate, which included a direct measure of the number of tests performed to identify 52% of reported cases, was 57.6%.

CONCLUSIONS

Most sexually active women aged 15 to 25 years in Washington State were screened for chlamydia in 2009. Healthcare Effectiveness Data and Information System methods may underestimate screening coverage. Health departments can derive population-based coverage estimates using data from large laboratories.

Assessing the role of prevention partnerships in STD prevention: a review of comprehensive STD prevention systems progress reports

Systematic analysis of STD programme data contributes to a national portrait of sexually transmitted disease (STD) prevention activities, including research and evaluation specifically designed to optimise programme efficiency and impact. We analysed the narrative of the 2009 annual progress reports of the US Comprehensive STD Prevention Systems cooperative agreement for 58 STD programmes, concentrating on programme characteristics and partnerships. Programmes described 516 unique partnerships with a median of seven organisations cited per STD programme. Non-profit organisations (including service providers) were most frequently cited. Higher gonorrhoea morbidity was associated with reporting more partnerships; budget problems were associated with reporting fewer. Challenges to engaging in partnerships included budget constraints, staff turnover and low interest. Data provide a source of information for judging progress in programme collaboration and for informing a sustained programme-focused research and evaluation agenda.

Chlamydial infection in vitamin D receptor knockout mice is more intense and prolonged than in wild-type mice

Vitamin D hormone (1,25-dihydroxyvitamin D) is involved in innate immunity and induces host defense peptides in epithelial cells, suggesting its involvement in mucosal defense against infections. Chlamydia trachomatis is a major cause of bacterial sexually transmitted disease worldwide. We tested the hypothesis that the vitamin D endocrine system would attenuate chlamydial infection. Vitamin D receptor knock-out mice (VDR(-/-)) and wild-type mice (VDR(+/+)) were infected with 10(3) inclusion forming units of Chlamydia muridarum and cervical epithelial cells (HeLa cells) were infected with C. muridarum at multiplicity of infection 5:1 in the presence and absence of 1,25-dihydroxyvitamin D3. VDR(-/-) mice exhibited significantly higher bacterial loading than wild-type VDR(+/+) mice (P<0.01) and cleared the chlamydial infection in 39 days, compared with 18 days for VDR(+/+) mice. Monocytes and neutrophils were more numerous in the uterus and oviduct of VDR(-/-) mice than in VDR(+/+) mice (P<0.05) at d 45 after infection. Pre-treatment of HeLa cells with 10nM or 100nM 1,25-dihydroxyvitamin D3 decreased the infectivity of C. muridarum (P<0.001). Several differentially expressed protein spots were detected by proteomic analysis of chlamydial-infected HeLa cells pre-treated with 1,25-dihydroxyvitamin D3. Leukocyte elastase inhibitor (LEI), an anti-inflammatory protein, was up-regulated. Expression of LEI in the ovary and oviduct of infected VDR(+/+) mice was greater than that of infected VDR(-/-) mice. We conclude that the vitamin D endocrine system reduces the risk for prolonged chlamydial infections through regulation of several proteins and that LEI is involved in its anti-inflammatory activity.

Identifying relationships between high-risk sexual behaviors and screening positive for chlamydia and gonorrhea in school-wide screening events

BACKGROUND

This article describes a school-wide sexually transmitted infection (STI) screening to identify adolescent high-risk sexual behaviors, STI history/incidence, and presence of chlamydia and gonorrhea, and examines relationships between high-risk behaviors and screening positive for chlamydia and gonorrhea in an alternative high school setting.

METHODS

School-wide chlamydia and gonorrhea education and screening was provided to 869 adolescents; 226 males and 282 females 14-20 years (mean age = 17.07) consented to urine screening. Relationships were examined between screening positive, history of STIs, and high-risk sexual behaviors.

RESULTS

A majority (69%) of the adolescents consented to screening: 17.76% (92) had a history of STI; 8.83% (46) tested positive at screening. More females than males tested positive (p = .001). Significant relationships existed between history of STIs and ≥ 4 sexual partners (p = .0022), no condom use (p = .06), and sexual intercourse in last 3 months (p = .03).

CONCLUSIONS

School-Based Health Center (SBHC) screening was well accepted by students and staff. Sexually transmitted infection history was correlated with all identified high-risk sexual behaviors supporting the need for in-depth assessment, counseling, and testing of adolescents wherever they present for care. This study also provides an example of the role SBHCs can play in the national strategy to control chlamydia and gonorrhea in adolescents.

A prospective study of the psychosocial impact of a positive Chlamydia trachomatis laboratory test

BACKGROUND

Few data exist on potential harms of chlamydia screening. We assessed the psychosocial impact of receiving a positive Chlamydia trachomatis test result.

METHODS

We prospectively studied women ≥16 years of age undergoing chlamydia testing in 2 Midwestern family planning clinics. We surveyed women at baseline and about 1 month after receiving test results, using 9 validated psychosocial scales/subscales and chlamydia-specific questions. Changes in scale scores were calculated for each woman. Mean percent changes in scores for chlamydia-positive and -negative women were compared using a t test.

RESULTS

We enrolled 1807 women (response rate, 84%). Of the 1688 women with test results, 149 (8.8%) tested positive. At follow-up, chlamydia-positive women (n = 71) had a 75% increase in anxiety about sexual aspects of their life on the Multidimensional Sexual Self-Concept Questionnaire (P < 0.001), significantly greater than the 26% increase among 280 randomly selected chlamydia-negative women (P = 0.02). There were no differences for the other 8 scales/subscales, including general measures of anxiety, depression, and self-esteem. Chlamydia-positive women were more likely than chlamydia-negative women to be "concerned about chlamydia" (80% vs. 40%, P < 0.001) and to report breaking up with a main partner (33% vs. 11%, P < 0.001) at follow-up. Women testing positive reported a range of chlamydia-specific concerns.

CONCLUSIONS

Chlamydia-positive women had significant increases in anxiety about sex and concern about chlamydia, but did not have marked changes in more general measures of psychosocial well-being about 1 month after diagnosis. Chlamydia diagnoses were associated with some disruption of relationships with main partners. Chlamydia-specific concerns may guide counseling messages to minimize psychosocial impact.

Intimate partner violence, mental health disorders, and sexually transmitted infections: important screening opportunities for pediatric healthcare providers

PURPOSE OF REVIEW

This article addresses three critical areas where pediatric healthcare providers must employ effective screening techniques to ensure the best care for patients: intimate partner violence (IPV), mental health issues, and sexually transmitted infections (STIs).

RECENT FINDINGS

IPV is now recognized as an important issue impacting the health of children. While long-term outcomes secondary to positive screening results are not known, routine, sensitive questioning can identify at-risk children and help connect families to resources in the community. Routine use of validated screening tools for mental health disorders (MHDs) in the office setting is now recommended. STIs disproportionately affect adolescents and young adults, yet timely diagnosis is often challenging because infections are frequently asymptomatic and adolescents may not be forthcoming about risk-taking behaviors. There is significant opportunity for pediatricians to improve screening rates of adolescents.

SUMMARY

Screening is an essential aspect of healthcare for pediatricians. An understanding of current screening recommendations for IPV, MHDs, and STIs will assist providers in earlier detection of medical problems in their patients and will likely improve patient outcomes.

Confusion regarding cervical cancer screening and chlamydia screening among sexually active young women

OBJECTIVE

The American Congress of Obstetricians and Gynecologists (ACOG) recently recommended that cervical cancer screening begin at 21 years of age and occur biennially for low-risk women younger than 30 years. Earlier studies suggested that women may have limited understanding of the differences between cervical cancer screening and chlamydia screening. This study assessed the knowledge of chlamydia and cervical cancer screening tests and schedules in younger women.

METHODS

A survey regarding knowledge of chlamydia and cervical cancer screening was administered to 60 younger women aged 18-25 years in an obstetrics and gynaecology clinic at an urban community health centre.

RESULTS

The majority of respondents recalled having had a Pap smear (93.3%) or chlamydia test (75.0%). Although many respondents understood that a Pap smear checks for cervical cancer (88.3%) and human papillomavirus (68.3%), 71.7% mistakenly believed that a Pap smear screens for chlamydia. No respondent correctly identified the revised cervical cancer screening schedule, and 83.3% selected annual screening. Few respondents (23.3%) identified the annual chlamydia screening schedule and 26.7% were unsure.

CONCLUSION

Many younger women in an urban community health centre believed that cervical cancer screening also screens for chlamydia and were confused about chlamydia screening schedules. As there is limited knowledge of the revised ACOG cervical cancer screening guidelines, there is a risk that currently low chlamydia screening rates may decrease further after these new guidelines are better known. Obstetrician gynaecologists and primary care providers should educate younger women about the differences between chlamydia and cervical cancer screening and encourage sexually active younger women to have annual chlamydia screening.

Chlamydia trachomatis infection among women reporting sexual activity with women screened in Family Planning Clinics in the Pacific Northwest, 1997 to 2005

OBJECTIVES

We sought to define Chlamydia trachomatis positivity among women who report sexual activity with women, a population for which sparse data on this infection are available and for whom health disparities including challenged access to comprehensive sexual and reproductive health services, have been reported.

METHODS

We analyzed data from 9358 family planning clinic visits with C trachomatis tests among women aged 15 to 24 years who reported sexual activity within the past year exclusively with women (WSW) or with men and women (WSMW), in the Region X Infertility Prevention Project. Characteristics were compared with women who reported sexual activity exclusively with men (WSM). Results. C trachomatis positivity among both WSW and WSMW was 7.1%, compared with 5.3% among WSM. Behavioral risks were more commonly reported by WSW and WSMW, compared with reports by WSM. Risks for C trachomatis positivity were comparable across groups and included younger age, non-White race, behavioral risks, and clinical signs.

CONCLUSIONS

Higher C trachomatis positivity among women reporting same-sex sexual behavior supports investigation into potential explanatory factors, including sexual behaviors, biological susceptibility, routine C trachomatis screening disparities, sexual identity disclosure, and sexual network assessment.

Home versus clinic-based specimen collection for Chlamydia trachomatis and Neisseria gonorrhoeae

Sexually transmitted infections (STIs) are a major public health concern that must be addressed with innovative screening methods to supplement traditional approaches. Home-based screening with self-collected urine or vaginal specimens is a highly feasible and acceptable method, and shows promise in improving STI screening rates in both men and women. Home collection kits have been offered in a variety of settings, with results ranging from very modest improvements in screening rates to 100-fold increases beyond the rates observed with clinic-based screening. This article describes and evaluates the effectiveness and limitations of various home screening strategies used for the detection of STIs.

Epidemiological features and determinants for Chlamydia trachomatis infection among women in Catalonia, Spain

We determined the prevalence of Chlamydia trachomatis (CT) infection and risk factors for its acquisition by women aged less than 35 years who were attending sexual health centres in the province of Barcelona in 2007. A convenience sample of 397 adolescents and young adult women aged between 16 and 35 years, stratified by age and recruitment site, were tested using realtime polymerase chain reaction by CT DNA. A standardized questionnaire was used to collect epidemiological and behavioural data on the participants, which were analysed in a multivariate logistic regression model. The overall prevalence of CT was 4%, significantly higher in those under 25 years of age (5.8% versus 1.6% over 25). The independent risk factors for CT infection were: foreign origin (odds ratio [OR] 4.7; confidence interval [CI] 1.02-21.8), having had a sexual partner in the last three months (OR 4.59; CI 1.16-18.08) and tobacco use the last 12 months (OR 6.38; CI 1.16-34.93). In conclusion, this is the first study performed in Catalonia showing a high prevalence of CT in young women, consistent with trends in the rest of Europe. Systematic monitoring of CT infection in sentinel populations such as this will inform future targeted screening programmes in our setting.

Risk behaviors among adolescent girls in an HIV prevention trial

Adolescent girls remain vulnerable to HIV and other sexually transmitted infections. Understanding their sexual and substance use behaviors is essential to designing effective interventions to reduce their risk. In this study, baseline data were analyzed from 738 adolescent girls ages 15 to 19 years in Rochester, New York. Data on sexual behavior and substance use (lifetime, past 3 months, and most recent sexual experience) were collected. Nearly one half of recent vaginal (42%) and anal (45%) sex acts were not condom protected; 39% had a prior sexually transmitted infection (STI) and 12% were currently infected with an STI. Approximately one third (31%) of girls had more than one sex partner in the past 3 months. Girls with multiple partners reported that their recent sexual experiences were more likely to involve drug and alcohol use by themselves and partners. Adolescent girls, particularly those with multiple sexual partners, continue to report high-risk sexual behaviors and need focused risk-reduction interventions.

Condom Use and Prevalence of Genital Chlamydia trachomatis Among the Korean Female Sex Workers

OBJECTIVES

Since 2004, availability of resources for preventing sexually transmitted diseases in Korean female sex workers (FSWs) has decreased because of strict application of a law against prostitution. This study is to evaluate the condom use and prevalence of Chlamydia trachomatis among FSWs in Korea.

METHODS

We performed a cross-sectional study of FSWs from 15 major sex work sites in Korea from June to November 2008, using convenience sampling. Self-administered questionnaires and urine samples were collected after all participants' written informed consent. Urine samples were analyzed with PCR at a single central laboratory.

RESULTS

Among 1,086 FSWs who consented to study participation, data from 999 FSWs were appropriate for analysis. C. trachomatis prevalence was 12.8% (95% CI: 10.7-14.9%). Younger age increased risk for C. trachomatis. Whereas majority of FSWs (71.0%) answered high self confidence in condom negotiation, the proportion of FSWs who always used condoms last month was only 23.7%. However, practicing regular condom use showed significant protection against chlamydia infection, not self confidence in condom negotiation.

CONCLUSION

In Korea, FSWs were not practicing enough self-protection at work with a high prevalence of C. trachomatis. Education for constant practice of protection against sexually transmitted diseases is needed, especially for younger FSWs.

Relative efficiency of chlamydia screening in non-clinical settings in two California counties

We examined the relative efficiency of non-clinical sites to screen for chlamydia in youth and young adults. Chlamydia screening targeting youth (under 30 years of age) was performed at non-clinical sites in high-morbidity neighbourhoods of two California counties. Venues were subdivided into community outreach, schools, parenting centres and drug treatment/correctional facilities. Relative efficiency was estimated with multivariate Poisson regression using incidence of chlamydia per person-hours labour adjusting for strategy and county. Among the 1514 youths screened, the overall prevalence of chlamydia was 5.5%. By venue, the highest prevalence was in drug treatment/correction facilities at 11.1% followed by parenting centres at 6.3%, community outreach at 4.9% and schools at 4.6%. Drug treatment/correctional facilities were the most labour time efficient at 9.9 person-hours per chlamydia case. Schools and parenting centres had the lowest cost per screen at 0.9 person-hours per screen. Adjusted relative labour time efficiency (chlamydia cases per paid person-hour) was significantly higher in schools, 2.0 (95% confidence interval [CI] 1.0-4.2), parenting centres, 3.2 (95% CI 1.6-6.6) and drug treatment/correctional facilities, 2.9 (95% CI 1.0-7.8), compared with community outreach. In conclusion, parenting centres and drug treatment centres and correctional facilities are the most efficient venues for chlamydia screening.