Individual and population level effects of partner notification for Chlamydia trachomatis

Partner notification by family physicians for sexually transmitted infections: Facilitators and barriers

OBJECTIVE

To explore Canadian FPs' experiences with, perceived barriers to, and perceived facilitators of FP-initiated partner notification (PN) for HIV and other sexually transmitted infections (STIs), as well as to inform the development of tools that might enhance this work.

DESIGN

Online survey.

SETTING

British Columbia.

PARTICIPANTS

A total of 146 FPs recruited through the Divisions of Family Practice community-based networks of FPs throughout the province.

MAIN OUTCOME MEASURES

Family physicians' current STI and PN practices, opinions regarding FP-initiated PN, perceived barriers to and facilitators of FP-initiated PN, and preferred PN resources.

RESULTS

More than 90% of FPs had diagnosed an STI within the past year, and most (60.3% to 96.6%, depending on the STI) told patients to inform their partners. Two-thirds (66.4%) felt that PN should not be done by FPs, and fewer than 10% reported contacting partners. Reported barriers included inaccurate or incomplete lists of partners (67.1%), poor compensation (54.1%), and insufficient time (54.1%). Facilitators chosen by respondents included another health professional assigned to follow up with PN (77.4%) and improved remuneration (74.7%). Electronic PN tools directed at patients (eg, PN slips) were favoured over resources directed at providers.

CONCLUSION

Family physicians regularly manage STIs and currently take part in PN primarily through educating index cases. However, most do not feel that PN should be conducted by FPs, and most believe that FP-initiated PN would require additional personnel, remuneration, and legal guidance.

Using an agent-based sexual-network model to analyze the impact of mitigation efforts for controlling chlamydia

Chlamydia trachomatis (Ct) is the most reported sexually transmitted infection in the United States, with a major cause of infertility, pelvic inflammatory disease, and ectopic pregnancy among women. Despite decades of screening women for Ct, rates increase among young African Americans (AA). We create and analyze a heterosexual agent-based network model to help understand the spread of Ct. We calibrate the model parameters to agree with survey data showing Ct prevalence of 12% of the women and 10% of the men in the 15-25 year-old AA in New Orleans, Louisiana. Our model accounts for both long-term and casual partnerships. The network captures the assortative mixing of individuals by preserving the joint-degree distributions observed in the data. We compare the effectiveness of intervention strategies based on randomly screening men, notifying partners of infected people, which includes partner treatment, partner screening, and rescreening for infection. We compare the difference between treating partners of an infected person both with and without testing them. We observe that although increased Ct screening, rescreening, and treating most of the partners of infected people will reduce the prevalence, these mitigations alone are not sufficient to control the epidemic. The current practice is to treat the partners of an infected individual without first testing them for infection. The model predicts that if a sufficient number of the partners of all infected people are tested and treated, then there is a threshold condition where the epidemic can be mitigated. This threshold results from the expanded treatment network created by treating an individual's infected partners' partners. Although these conclusions can help design future Ct mitigation studies, we caution the reader that these conclusions are for the mathematical model, not the real world, and are contingent on the validity of the model assumptions.

Contact tracing - Old models and new challenges

Contact tracing is an effective method to control emerging infectious diseases. Since the 1980's, modellers are developing a consistent theory for contact tracing, with the aim to find effective and efficient implementations, and to assess the effects of contact tracing on the spread of an infectious disease. Despite the progress made in the area, there remain important open questions. In addition, technological developments, especially in the field of molecular biology (genetic sequencing of pathogens) and modern communication (digital contact tracing), have posed new challenges for the modelling community. In the present paper, we discuss modelling approaches for contact tracing and identify some of the current challenges for the field.

Is Chlamydia trachomatis PCR Detection from Cervical Canal Swabs Associated with Tubal Obstruction?

Objective: To determine the relationship between a Chlamydia trachomatis PCR positive diagnosis from cervical canal swabs and the presence of tubal diseases among infertile women in Vietnam.

Methods: In this cross-sectional descriptive study, women who sought infertility treatment at the Center for Reproductive Endocrinology & Infertility, Hue University Hospital, Vietnam, from June 2016 to June 2017 were enrolled. All study participants were interviewed, and PCR tests were then performed to diagnose Chlamydia from cervical canal swabs. Hysterosalpingogram (HSG) was carried out to examine the uterine cavity and fallopian tubes.

Results: Among 568 women whose mean age was 32.0 ± 5.1 years, the prevalence of C. trachomatis infection as detected by PCR was 5.8%. Eighty-one percent (460/568) of infertile women had normal HSG results, and abnormal HSG results were more frequent in women over 35 years old, in women with secondary infertility, and in those with a history of miscarriage or genital tract infection. However, there was no relationship between C. trachomatis PCR positivity and HSG results in infertile women.

Conclusions: The diagnosis of C. trachomatis infection using the cervical swabs is the useful but not an effective method for routine practice for predicting tubal obstruction in infertile women.

Rapid point of care test for detecting urogenital Chlamydia trachomatis infection in nonpregnant women and men at reproductive age

BACKGROUND

Chlamydia trachomatis (C trachomatis) is one of the most frequent sexually transmitted infections and a source of deleterious effects on the reproductive health of men and women. Because this infection is likely asymptomatic and is associated with subfertility, ectopic pregnancy, and chronic pain, its presence needs to be confirmed. Technologies available for the diagnosis of C trachomatis infection can be classified into tests performed in a laboratory and rapid tests at the point of care (POC tests). Laboratory-based tests include culture, nucleic acid amplification tests, enzyme immunoassays (EIA), direct fluorescent antibody, nucleic acid hybridization, and transformation tests. Rapid tests include solid-phase EIA and solid-phase optical immunoassay. POC tests can be performed within 30 minutes without the need for expensive or sophisticated equipment. The principal advantage of this technology is the immediate presentation of results with the subsequent possibility to start the treatment of infected patients immediately.

OBJECTIVES

To determine the diagnostic accuracy of rapid point-of-care (POC) testing for detecting urogenital C trachomatis infection in nonpregnant women and men of reproductive age, as verified with nucleic acid amplification tests (NAATs) as the reference standard.

SEARCH METHODS

In November 2019 we searched CENTRAL, MEDLINE, Embase and LILACS. We also searched Web of Science, two trials registries and an abstract database. We screened reference lists of included studies for additional references.

SELECTION CRITERIA

We included diagnostic accuracy studies of symptomatic or asymptomatic nonpregnant women and men reproductive age. Included trials should have prospectively enrolled participants without previous diagnostic testing, co-infections or complications and consecutively or through random sampling at primary or secondary care facilities. Only studies reporting that all participants received the index test and the reference standard and presenting 2 x 2 data were eligible for inclusion. We excluded diagnostic case-control studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts for relevance. Two review authors independently, and in duplicate, assessed eligibility, extracted data, and carried out quality assessment. We resolved differences through consensus or by involving a third review author. We assessed studies for methodological quality using QUADAS-2 and used meta-analysis to combine the results of studies using the bivariate approach to estimate the expected sensitivity and specificity values. We assessed the quality of the evidence using GRADE criteria and explored sources of heterogeneity.

MAIN RESULTS

We included a total of 19 studies, with 13,676 participants, that assessed the diagnostic accuracy of POC tests for C trachomatis infection in nonpregnant women and men of reproductive age, as verified with NAATs as the reference standard. Rapid tests were provided by the distributors in nine studies. Seven studies recruited a predominantly high risk or symptomatic population; the studies were conducted in America, Asia, Africa, Europe and Oceania, with a median prevalence of 10% (range 8% to 28%); nine different brands were assessed. The mean sensitivity for rapid tests for detecting urogenital infection was 0.48 (95% confidence interval (CI) 0.39 to 0.58; low-quality evidence) with a mean specificity of 0.98 (95% CI 0.97 to 0.99; moderate-quality evidence). We explored sources of heterogeneity by looking into differences in diagnostic accuracy according to the specimen (endocervical versus urine or vaginal), symptoms among participants (symptomatic versus asymptomatic), and setting (low/middle-income versus high-income countries). Likelihood ratio tests were not significantly different in terms of sensitivity or specificity by specimen (P = 0.27) or setting (P = 0.28); for this reason, these covariates do not appear to explain the observed variability. Included studies did not provide enough information to assess the 'presence of symptoms' covariate. We downgraded the quality of evidence because of some limitations in applicability and heterogeneity.

AUTHORS' CONCLUSIONS

Based on the results of this systematic review, the POC test based on antigen detection has suboptimal sensitivity but good specificity. Performance of this test translates, on average, to a 52% chance of mistakenly indicating absence of infection and a 2% chance of mistakenly pointing to the presence of this condition. Because of its deleterious consequences for reproductive health, and considering the current availability of safe and effective interventions to treat C trachomatis infection, the POC screening strategy should not be based on a rapid diagnostic test for antigen detection. Research in this topic should focus on different technologies.

Gini coefficients for measuring the distribution of sexually transmitted infections among individuals with different levels of sexual activity

Objectives

Gini coefficients have been used to describe the distribution of Chlamydia trachomatis (CT) infections among individuals with different levels of sexual activity. The objectives of this study were to investigate Gini coefficients for different sexually transmitted infections (STIs), and to determine how STI control interventions might affect the Gini coefficient over time.

Methods

We used population-based data for sexually experienced women from two British National Surveys of Sexual Attitudes and Lifestyles (Natsal-2: 1999–2001; Natsal-3: 2010–2012) to calculate Gini coefficients for CT, Mycoplasma genitalium (MG), and human papillomavirus (HPV) types 6, 11, 16 and 18. We applied bootstrap methods to assess uncertainty and to compare Gini coefficients for different STIs. We then used a mathematical model of STI transmission to study how control interventions affect Gini coefficients.

Results

Gini coefficients for CT and MG were 0.33 (95% CI [0.18–0.49]) and 0.16 (95% CI [0.02–0.36]), respectively. The relatively small coefficient for MG suggests a longer infectious duration compared with CT. The coefficients for HPV types 6, 11, 16 and 18 ranged from 0.15 to 0.38. During the decade between Natsal-2 and Natsal-3, the Gini coefficient for CT did not change. The transmission model shows that higher STI treatment rates are expected to reduce prevalence and increase the Gini coefficient of STIs. In contrast, increased condom use reduces STI prevalence but does not affect the Gini coefficient.

Conclusions

Gini coefficients for STIs can help us to understand the distribution of STIs in the population, according to level of sexual activity, and could be used to inform STI prevention and treatment strategies.

Double trouble: modelling the impact of low risk perception and high-risk sexual behaviour on chlamydia transmission

Risk perception plays an important role in testing behaviour for sexually transmitted infections, but is rarely included in mathematical models exploring the impact of testing. We explored the impact of incorporating sexual behaviour (SB), risk perception (RP) and differential testing uptake in SB-RP groups on prevalence, using chlamydia as an example. We developed a pair model with a susceptible-infected-susceptible structure representing heterosexuals aged 16-26 years. The effect of testing on chlamydia prevalence was compared between a model with only SB (SB model) and a model with SB and RP (SB-RP model). In the SB-RP model, a scenario without differential testing uptake in SB-RP groups was compared to scenarios with differential testing uptake in SB-RP groups. Introducing testing into the SB-RP model resulted in a slightly smaller reduction in chlamydia prevalence (-38.0%) as compared to the SB model (-40.4%). In the SB-RP model, the scenario without differential testing uptake in SB-RP groups overestimated the reduction in chlamydia prevalence (with 4.8%), especially in the group with high SB and low RP (19.8%). We conclude that mathematical models incorporating RP and differential testing uptake in SB-RP groups improve the impact assessment of testing and treatment on chlamydia prevalence.

Does infection with Chlamydia trachomatis induce long-lasting partial immunity? Insights from mathematical modelling

OBJECTIVES

To explore whether existence of long-lasting partial immunity against reinfection with Chlamydia trachomatis is necessary to explain C. trachomatis prevalence patterns by age and sexual risk, and to provide a plausible estimate for the effect size, defined here as a reduction in susceptibility to reinfection.

METHODS

A population-based mathematical model was constructed to describe C. trachomatis natural history and transmission dynamics by age and sexual risk. The model was parameterised using natural history, and epidemiological and sexual behaviour data, and applied for UK and US data. Sensitivity analyses were conducted to assess the robustness of predictions to variations in model structure and to examine the impact of alternative assumptions for the mechanism underlying partial immunity.

RESULTS

Partial immunity against reinfection was found necessary to explain observed C. trachomatis prevalence patterns by age and sexual risk. The reduction in susceptibility to reinfection was estimated at 93% using UK data (95% uncertainty interval (UI)=88%-97%) and at 67% using US data (95% UI=24%-88%). The model-structure sensitivity analyses affirmed model predictions. The immunity-mechanism sensitivity analyses suggested a mechanism of susceptibility reduction against reinfection or a mechanism of infectious-period duration reduction upon reinfection.

CONCLUSIONS

A strong long-lasting partial immunity against C. trachomatis reinfection should be present to explain observed prevalence patterns. The mechanism of immunity could be either a reduction in susceptibility to reinfection or a reduction in duration of infection on reinfection. C. trachomatis infection appears to naturally elicit a strong long-lasting immune response, supporting the concept of vaccine development.

Age difference between heterosexual partners in Britain: Implications for the spread of Chlamydia trachomatis

Heterosexual partners often differ in age. Integrating realistic patterns of sexual mixing by age into dynamic transmission models has been challenging. The effects of these patterns on the transmission of sexually transmitted infections (STI) including Chlamydia trachomatis (chlamydia), the most common bacterial STI are not well understood. We describe age mixing between new heterosexual partners using age- and sex-specific data about sexual behavior reported by people aged 16-63 years in the 2000 and 2010 British National Surveys of Sexual Attitudes and Lifestyles. We incorporate mixing patterns into a compartmental transmission model fitted to age- and sex-specific, chlamydia positivity from the same surveys, to investigate C. trachomatis transmission. We show that distributions of ages of new sex partners reported by women and by men in Britain are not consistent with each other. After balancing these distributions, new heterosexual partnerships tend to involve men who are older than women (median age difference 2, IQR -1, 5 years). We identified the most likely age combinations of heterosexual partners where incident C. trachomatis infections are generated. The model results show that in >50% of chlamydia transmitting partnerships, at least one partner is ≥25 years old. This study illustrates how sexual behavior data can be used to reconstruct detailed sexual mixing patterns by age, and how these patterns can be integrated into dynamic transmission models. The proposed framework can be extended to study the effects of age-dependent transmission on incidence in any STI.

Partner notification and partner treatment for chlamydia: attitude and practice of general practitioners in the Netherlands; a landscape analysis

BACKGROUND

Chlamydia prevalence remains high despite scaling-up control efforts. Transmission is not effectively interrupted without partner notification (PN) and (timely) partner treatment (PT). In the Netherlands, the follow-up of partners is not standardized and may depend on GPs' time and priorities. We investigated current practice and attitude of GPs towards PN and PT to determine the potential for Patient-Initiated Partner Treatment, which is legally not supported yet.

METHODS

Multiple data-sources were combined for a landscape analysis. Quantitative data on (potential) PT were obtained from prescriptions in the national pharmacy register (2004-2014) and electronic patient data from NIVEL-Primary Care Database (PCD) and from STI consultations in a subgroup of sentinel practices therein. Furthermore, we collected information on current practice via two short questionnaires at a national GP conference and obtained insight into GPs' attitudes towards PN/PT in a vignette study among GPs partaking in NIVEL-PCD.

RESULTS

Prescription data showed Azithromycin double dosages in 1-2% of cases in the pharmacy register (37.000 per year); probable chlamydia-specific repeated prescriptions or double dosages of other antibiotics in NIVEL-PCD (115/1078) could not be interpreted as PT for chlamydia with certainty. STI consultation data revealed direct PT in 6/100 cases, via partner prescription or double doses. In the questionnaires the large majority of GPs (>95% of 1411) reported to discuss PN of current and ex-partner(s) with chlamydia patients. Direct PT was indicated as most common method by 4% of 271 GPs overall and by 12% for partners registered in the same practice. Usually, GPs leave further steps to the patients (83%), advising patients to tell partners to get tested (56%) or treated (28%). In the vignette study, 16-20% of 268 GPs indicated willingness to provide direct PT, depending on patient/partner profile, more (24-45%) if patients would have the chance to notify their partner first.

CONCLUSION

GPs in the Netherlands already treat some partners of chlamydia cases directly, especially partners registered in the same practice. Follow-up of partner notification and treatment in general practice needs more attention. GPs may be open to implement PIPT more often, provided there are clear guidelines to arrange this legally and practically.

Modeling the consequences of regional heterogeneity in human papillomavirus (HPV) vaccination uptake on transmission in Switzerland

BACKGROUND

Completed human papillomavirus (HPV) vaccination by age 16 years among women in Switzerland ranges from 17 to 75% across 26 cantons. The consequences of regional heterogeneity in vaccination coverage on transmission and prevalence of HPV-16 are unclear.

METHODS

We developed a deterministic, population-based model that describes HPV-16 transmission among young adults within and between the 26 cantons of Switzerland. We parameterized the model using sexual behavior data from Switzerland and data from the Swiss National Vaccination Coverage Survey. First, we investigated the general consequences of heterogeneity in vaccination uptake between two sub-populations. We then compared the predicted prevalence of HPV-16 resulting from heterogeneous HPV vaccination uptake in all of Switzerland with homogeneous vaccination at an uptake that is identical to the national average (52%).

RESULTS

In our baseline scenario, HPV-16 prevalence in women is 3.34% when vaccination is introduced and begins to diverge across cantons, ranging from 0.19 to 1.20% after 15 years of vaccination. After the same time period, overall prevalence of HPV-16 in Switzerland is only marginally higher (0.63%) with heterogeneous vaccination uptake than with homogeneous uptake (0.59%). Assuming inter-cantonal sexual mixing, cantons with low vaccination uptake benefit from a reduction in prevalence at the expense of cantons with high vaccination uptake.

CONCLUSIONS

Regional variations in uptake diminish the overall effect of vaccination on HPV-16 prevalence in Switzerland, but the effect size is small. Cantonal efforts towards HPV-prevalence reduction by increasing vaccination uptake are impaired by cantons with low vaccination uptake. Although the expected impact on national prevalence would be relatively small, harmonization of cantonal vaccination programs would reduce inter-cantonal differences in HPV-16 prevalence.

Pair formation models for sexually transmitted infections: A primer

For modelling sexually transmitted infections, duration of partnerships can strongly influence the transmission dynamics of the infection. If partnerships are monogamous, pairs of susceptible individuals are protected from becoming infected, while pairs of infected individuals delay onward transmission of the infection as long as they persist. In addition, for curable infections re-infection from an infected partner may occur. Furthermore, interventions based on contact tracing rely on the possibility of identifying and treating partners of infected individuals. To reflect these features in a mathematical model, pair formation models were introduced to mathematical epidemiology in the 1980's. They have since been developed into a widely used tool in modelling sexually transmitted infections and the impact of interventions. Here we give a basic introduction to the concepts of pair formation models for a susceptible-infected-susceptible (SIS) epidemic. We review some results and applications of pair formation models mainly in the context of chlamydia infection.

Evaluation of Chlamydia Partner Notification Practices and Use of the "Let Them Know" Website by Family Planning Clinicians in Australia: Cross-Sectional Study

Background

Chlamydia, caused by Chlamydia trachomatis, is the most common reportable infection in many developed countries. Testing, treatment, and partner notification (PN) are key strategies for chlamydia control. In 2008 the Let Them Know (LTK) PN website was established, which provided means for people to send anonymous PN messages by text messaging (short message service, SMS), email, or letter.

Objective

We evaluated PN practices among Australian family planning clinicians following chlamydia diagnosis and assessed how often clinicians refer their patients to the LTK website.

Methods

A mixed methods approach included a Web-based cross-sectional survey of Australian family planning clinicians to examine PN attitudes and practices and focus groups to explore the context of LTK website use.

Results

Between May 2012 and June 2012, all clinicians from 29 different family planning services (n=212) were invited to complete the survey, and 164 participated (response rate=77.4%); of the clinicians, 96.3% (158/164) were females, 56.1% (92/164) nurses, and 43.9% (72/164) doctors. More than half (62.2%, 92/148) agreed that PN was primarily the client's responsibility; however, 93.2% (138/148) agreed it was the clinician's responsibility to support the client in informing their partners by providing information or access to resources. Almost half (49.4%, 76/154) of the clinicians said that they always or usually referred clients to the LTK website, with variation across clinics in Australian states and territories (0%-77%). Eleven focus groups among 70 clinicians at 11 family planning services found that the LTK website had been integrated into routine practice; that it was particularly useful for clients who found it difficult to contact partners; and that the LTK letters and fact sheets were useful. However, many clinicians were not aware of the website and noted a lack of internal clinic training about LTK.

Conclusions

The LTK website has become an important PN tool for family planning clinicians. The variation in referral of patients to the LTK website and lack of awareness among some clinicians suggest further promotion of the website, PN training, and clinic protocols are warranted.

Antibiotic-Resistant Neisseria gonorrhoeae Spread Faster with More Treatment, Not More Sexual Partners

The sexually transmitted bacterium Neisseria gonorrhoeae has developed resistance to all antibiotic classes that have been used for treatment and strains resistant to multiple antibiotic classes have evolved. In many countries, there is only one antibiotic remaining for empirical N. gonorrhoeae treatment, and antibiotic management to counteract resistance spread is urgently needed. Understanding dynamics and drivers of resistance spread can provide an improved rationale for antibiotic management. In our study, we first used antibiotic resistance surveillance data to estimate the rates at which antibiotic-resistant N. gonorrhoeae spread in two host populations, heterosexual men (HetM) and men who have sex with men (MSM). We found higher rates of spread for MSM (0.86 to 2.38 y⁻¹, mean doubling time: 6 months) compared to HetM (0.24 to 0.86 y⁻¹, mean doubling time: 16 months). We then developed a dynamic transmission model to reproduce the observed dynamics of N. gonorrhoeae transmission in populations of heterosexual men and women (HMW) and MSM. We parameterized the model using sexual behavior data and calibrated it to N. gonorrhoeae prevalence and incidence data. In the model, antibiotic-resistant N. gonorrhoeae spread with a median rate of 0.88 y⁻¹ in HMW and 3.12 y⁻¹ in MSM. These rates correspond to median doubling times of 9 (HMW) and 3 (MSM) months. Assuming no fitness costs, the model shows the difference in the host population’s treatment rate rather than the difference in the number of sexual partners explains the differential spread of resistance. As higher treatment rates result in faster spread of antibiotic resistance, treatment recommendations for N. gonorrhoeae should carefully balance prevention of infection and avoidance of resistance spread.

More and more infectious disease treatments fail because the causative pathogens are resistant to the drugs used for treatment. For the treatment of Neisseria gonorrhoeae, a sexually transmitted bacterium, drug resistance is a particularly big problem: there is only a single antibiotic left that is recommended for treatment. We aimed to understand how antibiotic-resistant N. gonorrhoeae spread in a sexually active host population and how the spread of resistance can be slowed. From antibiotic resistance surveillance data, we first estimated the rate at which antibiotic-resistant N. gonorrhoeae spread. Second, we reproduced the observed dynamics in a mathematical model describing the transmission between hosts. We found that antibiotic-resistant N. gonorrhoeae spread faster in host populations of men who have sex with men than in host populations of heterosexuals. We could attribute the faster spread of resistant pathogens to higher treatment rates. This finding implies that promoting screening to control antibiotic-resistant N. gonorrhoeae could in fact accelerate their spread.

Background review for the '2015 European guideline on the management of Chlamydia trachomatis infections'

SummaryChlamydia trachomatis infections are major public health concerns globally. Of particular grave concern is that the majority of persons with anogenital Chlamydia trachomatis infections are asymptomatic and accordingly not aware of their infection, and this silent infection can subsequently result in severe reproductive tract complications and sequelae. The current review paper provides all background, evidence base and discussions for the 2015 European guideline on the management of Chlamydia trachomatis infections (Lanjouw E, et al. Int J STD AIDS 2015). Comprehensive information and recommendations are included regarding the diagnosis, treatment and prevention of anogenital, pharyngeal and conjunctival Chlamydia trachomatis infections in European countries. However, Chlamydia trachomatis also causes the eye infection trachoma, which is not a sexually transmitted infection. The 2015 European Chlamydia trachomatis guideline provides up-to-date guidance regarding broader indications for testing and treatment of Chlamydia trachomatis infections; clearer recommendation of using validated nucleic acid amplification tests only for diagnosis; advice on (repeated) Chlamydia trachomatis testing; recommendation of increased testing to reduce the incidence of pelvic inflammatory disease and prevent exposure to infection and recommendations to identify, verify and report Chlamydia trachomatis variants. Improvement of access to testing, test performance, diagnostics, antimicrobial treatment and follow-up of Chlamydia trachomatis patients are crucial to control its spread.

2015 European guideline on the management of Chlamydia trachomatis infections

Chlamydia trachomatis infections, which most frequently are asymptomatic, are major public health concerns globally. The 2015 European C. trachomatis guideline provides: up-to-date guidance regarding broader indications for testing and treatment of C. trachomatis infections; a clearer recommendation of using exclusively-validated nucleic acid amplification tests for diagnosis; advice on (repeated) C. trachomatis testing; the recommendation of increased testing to reduce the incidence of pelvic inflammatory disease and prevent exposure to infection; and recommendations to identify, verify and report C. trachomatis variants. Improvement of access to testing, test performance, diagnostics, antimicrobial treatment and follow-up of C. trachomatis patients are crucial to control its spread. For detailed background, evidence base and discussions, see the background review for the present 2015 European guideline on the management of Chlamydia trachomatis infections (Lanjouw E, et al. Int J STD AIDS. 2015).

Adolescent patient preferences surrounding partner notification and treatment for sexually transmitted infections

OBJECTIVES

Important barriers to addressing the sexually transmitted infection (STI) epidemic among adolescents are the inadequate partner notification of positive STI results and insufficient rates of partner testing and treatment. However, adolescent attitudes regarding partner notification and treatment are not well understood. The aim was to qualitatively explore the barriers to and preferences for partner notification and treatment among adolescent males and females tested for STIs in an emergency department (ED) setting and to explore the acceptability of ED personnel notifying their sexual partners.

METHODS

This was a descriptive, qualitative study in which a convenience sample of 40 adolescents (18 females, 22 males) 14 to 21 years of age who presented to either adult or pediatric EDs with STI-related complaints participated. Individualized, semistructured, confidential interviews were administered to each participant. Interviews were audiotaped and transcribed verbatim by an independent transcriptionist. Data were analyzed using framework analysis.

RESULTS

Barriers to partner notification included fear of retaliation or loss of the relationship, lack of understanding of or concern for the consequences associated with an STI, and social stigma and embarrassment. Participants reported two primary barriers to their partners obtaining STI testing and treatment: lack of transportation to the health care site and the partner's fear of STI positive test results. Most participants preferred to notify their main sexual partners of an STI exposure via a face-to-face interaction or a phone call. Most participants were agreeable with a health care provider (HCP) notifying their main sexual partners of STI exposure and preferred that the HCP notify the partner by phone call.

CONCLUSIONS

There are several adolescent preferences and barriers for partner notification and treatment. To be most effective, future interventions to prevent adolescent STIs should incorporate these preferences and address the barriers to partner notification. In an ED setting, using HCPs to provide partner notification of STI exposures is acceptable to adolescent patients; however, the feasibility of this type of program needs further exploration.

Chlamydia screening strategies and outcomes in educational settings: a systematic review

Chlamydia trachomatis (CT) screening programs have been established in educational settings in many countries during the past 2 decades. However, recent evidence suggests that high uptake of screening and management (treatment, partner notification, and retesting for reinfection) improves program effectiveness. We conducted a systematic review to understand the screening strategies, the extent of screening conducted, and uptake of management strategies in educational settings. Screening studies in educational settings were identified through a systematic search of published literature from 2005 to 2011. We identified 27 studies describing 30 screening programs in the United States/Canada (n = 10), Europe (n = 8), Australia/New Zealand (n = 5), and Asia (n = 4). Most studies targeted both male and female students (74%). Classroom-based strategies resulted in 21,117 testes overall (4 programs), followed by opportunistic screening during routine health examination (n = 13,470; 5 programs) and opportunistic screening at school-based health centers (n = 13,006; 5 programs). The overall median CT positivity was 4.7% (range, 1.3%-18.1%). Only 5 programs reported treatment rates (median, 100%; range, 86%-100%), 1 partner notification rate (71%), 1 retesting rate within a year of an initial CT diagnosis (47%), and 2 reported repeat positivity rates (21.1% and 26.3%). In conclusion, this systematic review shows that a variety of strategies have been used to screen large numbers of students in educational settings; however, only a few studies have reported CT management outcomes.

Using HIV networks to inform real time prevention interventions

Objective

To reconstruct the local HIV-1 transmission network from 1996 to 2011 and use network data to evaluate and guide efforts to interrupt transmission.

Design

HIV-1 pol sequence data were analyzed to infer the local transmission network.

Methods

We analyzed HIV-1 pol sequence data to infer a partial local transmission network among 478 recently HIV-1 infected persons and 170 of their sexual and social contacts in San Diego, California. A transmission network score (TNS) was developed to estimate the risk of HIV transmission from a newly diagnosed individual to a new partner and target prevention interventions.

Results

HIV-1 pol sequences from 339 individuals (52.3%) were highly similar to sequences from at least one other participant (i.e., clustered). A high TNS (top 25%) was significantly correlated with baseline risk behaviors (number of unique sexual partners and insertive unprotected anal intercourse (p = 0.014 and p = 0.0455, respectively) and predicted risk of transmission (p<0.0001). Retrospective analysis of antiretroviral therapy (ART) use, and simulations of ART targeted to individuals with the highest TNS, showed significantly reduced network level HIV transmission (p<0.05).

Conclusions

Sequence data from an HIV-1 screening program focused on recently infected persons and their social and sexual contacts enabled the characterization of a highly connected transmission network. The network-based risk score (TNS) was highly correlated with transmission risk behaviors and outcomes, and can be used identify and target effective prevention interventions, like ART, to those at a greater risk for HIV-1 transmission.

Improved partner notification for genital chlamydia can be achieved by centralisation of the duty to a specially trained team

Partner notification is mandatory for Chlamydia trachomatis infections in Sweden. A significant quality improvement of partner notification for genital chlamydia was achieved by increasing the skills and reducing the number of individuals conducting partner notifications. By centralisation of the partner notification to a specially trained team of nurses, an additional 12% of genital chlamydia cases were found. Routine partner notification achieved a score of 3.3 notified partners per index case, and shows how important this activity is for detection of asymptomatic chlamydia infections in the community.

Defining research priorities for bacterial sexually transmitted infections in Canada

OBJECTIVES

We aimed to define priority areas for research on chlamydia, gonorrhea, and syphilis in Canada through the use of a consensus method.

METHODS

A modified Delphi method was conducted, consisting of two online surveys and an in-person meeting. Participants included people working in bacterial sexually transmitted infections (STIs) across Canada, including clinicians, policy-makers, public health practitioners, and researchers.

RESULTS

Consensus was achieved regarding the most important priority topics in bacterial STI research in Canada, within five general priority areas: the epidemiology of bacterial STIs, screening, partner notification and contact tracing, antimicrobial resistance, and identification of best practices for the prevention and control of bacterial STIs.

CONCLUSIONS

The findings of this consensus process can be used to inform research efforts, which could contribute to more effective control of bacterial STIs in Canada.

Reinfection by untreated partners of people treated for Chlamydia trachomatis and Neisseria gonorrhoeae: mathematical modelling study

OBJECTIVES

Reinfection after treatment for Chlamydia trachomatis or Neisseria gonorrhoeae reduces the effect of control interventions. We explored the impact of delays in treatment of current partners on the expected probability of reinfection of index cases using a mathematical model.

METHODS

We used previously reported parameter distributions to calculate the probability that index cases would be reinfected by their untreated partners. We then assumed different delays between index case and partner treatment to calculate the probabilities of reinfection.

RESULTS

In the absence of partner treatment, the medians of the expected reinfection probabilities are 19.4% (IQR 9.2-31.6%) for C trachomatis and 12.5% (IQR 5.6-22.2%) for N gonorrhoeae. If all current partners receive treatment 3 days after the index case, the expected reinfection probabilities are 4.2% (IQR 2.1-6.9%) for C trachomatis and 5.5% (IQR 2.6-9.5%) for N gonorrhoeae.

CONCLUSIONS

Quicker partner referral and treatment can substantially reduce reinfection rates for C trachomatis and N gonorrhoeae by untreated partners. The formula we used to calculate reinfection rates can be used to inform the design of randomised controlled trials of novel partner notification technologies like accelerated partner therapy.