The potential for quality assurance systems to save costs and lives: the case of early infant diagnosis of HIV.

OBJECTIVES: Scaling up of point-of-care testing (POCT) for early infant diagnosis of HIV (EID) could reduce the large gap in infant testing. However, suboptimal POCT EID could have limited impact and potentially high avoidable costs. This study models the cost-effectiveness of a quality assurance system to address testing performance and screening interruptions, due to, for example, supply stockouts, in Kenya, Senegal, South Africa, Uganda and Zimbabwe, with varying HIV epidemics and different health systems. METHODS: We modelled a quality assurance system-raised EID quality from suboptimal levels: that is, from misdiagnosis rates of 5%, 10% and 20% and EID testing interruptions in months, to uninterrupted optimal performance (98.5% sensitivity, 99.9% specificity). For each country, we estimated the 1-year impact and cost-effectiveness (US$/DALY averted) of improved scenarios in averting missed HIV infections and unneeded HIV treatment costs for false-positive diagnoses. RESULTS: The modelled 1-year costs of a national POCT quality assurance system range from US$ 69 359 in South Africa to US$ 334 341 in Zimbabwe. At the country level, quality assurance systems could potentially avert between 36 and 711 missed infections (i.e. false negatives) per year and unneeded treatment costs between US$ 5808 and US$ 739 030. CONCLUSIONS: The model estimates adding effective quality assurance systems are cost-saving in four of the five countries within the first year. Starting EQA requires an initial investment but will provide a positive return on investment within five years by averting the costs of misdiagnoses and would be even more efficient if implemented across multiple applications of POCT.

OBJECTIFS: L'intensification du dépistage au point des soins (DPS) pour le diagnostic précoce du VIH chez le nourrisson (DPVN) pourrait réduire le grand écart dans le dépistage des nourrissons. Cependant, un DPVN DPS sous-optimal pourrait avoir un impact limité et des coûts évitables potentiellement élevés. Cette étude modélise la rentabilité d'un système d'assurance qualité pour traiter les performances des tests et les interruptions de dépistage, dues par exemple à des ruptures de stock, au Kenya, au Sénégal, en Afrique du Sud, en Ouganda et au Zimbabwe, avec des épidémies variables du VIH et des systèmes de santé différents. MÉTHODES: Nous avons modélisé une qualité de DPVN soulevée par le système d'assurance qualité à partir de niveaux sous-optimaux: c'est-à-dire des taux d'erreurs de diagnostic de 5%, 10% et 20% et des interruptions des tests de DPVN en mois, à des performances optimales ininterrompues (sensibilité de 98,5%, spécificité de 99,9%). Pour chaque pays, nous avons estimé l'impact sur un an et la rentabilité (en USD/DALY évitée) de scénarios améliorés pour éviter les infections à VIH manquées et les coûts inutiles de traitement du VIH pour les diagnostics faux positifs. RÉSULTATS: Les coûts modélisés sur un an d'un système national d'assurance qualité DPS vont de 69.359 USD en Afrique du Sud à 334.341 USD au Zimbabwe. Au niveau des pays, les systèmes d'assurance de la qualité pourraient potentiellement éviter entre 36 et 711 infections manquées (c'est-à-dire des faux négatifs) par an et des coûts de traitement inutiles entre 5.808 et 739.030 USD. CONCLUSIONS: Le modèle estime que l'ajout de systèmes d'assurance qualité efficaces permet de réaliser des économies dans quatre des cinq pays au cours de la première année. Le lancement de l'assurance qualité nécessite un investissement initial, mais fournira un retour sur investissement positif dans les cinq ans en évitant les coûts des diagnostics erronés et serait encore plus efficace s'il était mis en œuvre dans plusieurs applications de DPS.

Rapid diagnostic tests for determining dengue serostatus: a systematic review and key informant interviews.

OBJECTIVES: Vaccination for dengue with the live attenuated tetravalent CYD-TDV vaccine (Dengvaxia®) is only recommended in individuals who have had prior dengue virus (DENV) infection. Rapid diagnostic tests (RDT) for past DENV infection would offer a convenient method for pre-vaccination screening at point-of-care. A systematic review was conducted to evaluate the performance of current dengue RDTs for determining dengue serostatus, using IgG antibodies against DENV as a marker of past infection. METHODS: PubMed and EMBASE databases were searched from 2000 to 2018 to identify studies evaluating dengue RDTs in individuals with known or possible previous DENV infection. Study quality was evaluated using GRADE and QUADAS-2 criteria. Semi-structured interviews were also performed with available dengue RDT manufacturers. RESULTS: The performance of four dengue IgG RDTs was determined in 3137 individuals across ten studies conducted in 13 countries, with serum used in most of the studies. No studies reported data for determining dengue serostatus, and limited data were available regarding cross-reactivity with other viruses. The majority of studies demonstrated sensitivities and specificities between 80% and 100% for dengue IgG detection in samples from secondary infection or convalescent time-points after recent infection. CONCLUSIONS: Although current dengue IgG RDTs have shown reasonable performance compared with laboratory-based tests in secondary infection, additional research is needed to determine how RDTs would perform in relevant populations targeted for vaccination. New RDTs or modifications to current RDTs are feasible and may optimize the performance of these tests for use in a pre-vaccination screening approach.

Field performance of a rapid point-of-care diagnostic test for antenatal syphilis screening in the Amazon region, Brazil.

We evaluated an immunochromatographic point-of-care (POC) syphilis test in 712 pregnant women under field conditions in remote communities of the Amazon region (Brazil), and identified risk factors for syphilis. Women were screened by POC test using whole blood obtained by fingerprick, the fluorescent treponemal antibody absorption (FTA-Abs) test as the gold standard and the Venereal Diseases Research Laboratory (VDRL) test to determine test performance in active syphilis. Multivariate analysis was conducted to identify factors associated with syphilis infection. Among women, 2.2% had syphilis (positive FTA-Abs) and 0.8% active syphilis (FTA-Abs and VDRL positive). In all, 2.2% of samples were positive by the POC test. The sensitivity, specificity, positive and negative predictive values were 62.5% (95% confidence interval [CI]: 38.6-81.5), 99.1% (95% CI: 98.1-99.6), 62.5% (95% CI: 38.6-81.5) and 99.1% (95% CI: 98.1-99.6), respectively. The POC test identified 62.5% (10/16) of syphilis cases, 66.7% (4/6) of active syphilis cases and all high-titre syphilis cases (VDRL > 1:8). Older age was associated with syphilis infection. The rapid test performed moderately well as a screening tool for low-risk populations. This combined with on-site testing and same day treatment could expand antenatal syphilis screening programmes in distant communities characterized by difficult access to antenatal services and infrequent clinical follow-up visits.

Towards new business models for R&D for novel antibiotics.

In the face of a growing global burden of resistance to existing antibiotics, a combination of scientific and economic challenges has posed significant barriers to the development of novel antibacterials over the past few decades. Yet the bottlenecks at each stage of the pharmaceutical value chain-from discovery to post-marketing-present opportunities to reengineer an innovation pipeline that has fallen short. The upstream hurdles to lead identification and optimization may be eased with greater multi-sectoral collaboration, a growing array of alternatives to high-throughput screening, and the application of open source approaches. Product development partnerships and South-South innovation platforms have shown promise in bolstering the R&D efforts to tackle neglected diseases. Strategies that delink product sales from the firms' return on investment can help ensure that the twin goals of innovation and access are met. To effect these changes, both public and private sector stakeholders must show greater commitment to an R&D agenda that will address this problem, not only for industrialized countries but also globally.

The TDR Tuberculosis Specimen Bank: a resource for diagnostic test developers.

BACKGROUND: The Special Programme for Research and Training in Tropical Diseases established a specimen bank in 1999 to support the development and evaluation of new tuberculosis (TB) diagnostic tools. OBJECTIVE: To provide a narrative of the bank's development and discuss lessons learned, the bank's limitations and potential future applications. RESULTS: Collection sites were selected in high- and low-prevalence settings. Patients with TB symptoms, consenting to participate and to undergo human immunodeficiency virus testing were enrolled and diagnosed. Serum, sputum, saliva and urine samples were collected and sent to the bank's repositories. The bank has stocked 41,437 samples from 2524 patients at 11 sites worldwide. Ninety-five requests for specimens have been reviewed and 67 sets have been approved. Approved applicants have received sets of 20 or 200 samples. The bank allowed an evaluation of 19 commercial lateral flow tests and showed that none of them had broad global utility for TB diagnosis. CONCLUSIONS: The establishment and development of the specimen bank have provided a wealth of experience. It is fulfilling a need to provide quality specimens, but the type and number of samples may not fulfil the demands of future end-users. Plans are underway to review the mechanisms of specimen collection and distribution to maximise their impact on product development.

Point-of-care tests for diagnosing infections in the developing world.

Infectious diseases continue to cause an enormous burden of death and disability in developing countries. Increasing access to appropriate treatment for infectious diseases could have a major impact on disease burden. Some common infections can be managed syndromically without the need for diagnostic tests, but this is not appropriate for many infectious diseases, in which a positive diagnostic test is needed before treatment can be given. Since many people in developing countries do not have access to laboratory services, diagnosis depends on the availability of point of care (POC) tests. Historically there has been little investment in POC tests for diseases that are common in developing countries, but that is now changing. Lack of regulation of diagnostic tests in many countries has resulted in the widespread use of sub-standard POC tests, especially for malaria, making it difficult for manufacturers of reliable POC tests to compete. In recent years increased investment, technological advances, and greater awareness about the importance of reliable diagnostic tests has resulted in rapid progress. Rapid, reliable and affordable POC tests, requiring no equipment and minimal training, are now available for HIV infection, syphilis and malaria, but POC tests for other infections are urgently needed. Many countries do not have established criteria for licensing and introducing new diagnostic tests, and many clinicians in developing countries have become disillusioned with diagnostic tests and prefer to rely on clinical judgment. Continuing advocacy and training in the use of POC tests are needed, and systems for quality control of POC tests need to be developed if they are to achieve their maximum potential.

Host genetic contribution to the cellular immune response to Chlamydia trachomatis: Heritability estimate from a Gambian twin study.

If the cellular immune response to Chlamydia trachomatis is subject to genetic influences, the degree and mechanisms of such genetic control may have important implications for vaccine development. We estimated the relative contribution of host genetics to the total variation in lymphoproliferative responses to C. trachomatis antigen by analyzing these responses in 64 Gambian twin pairs from trachoma endemic areas. Zygosity was determined by restriction fragment length polymorphism analysis of minisatellite probes and microsatellite typing. Proliferative responses to serovar A elementary body antigen were estimated in monozygotic (MZ) and dizygotic (DZ) twin pairs. We found a stronger correlation and lower within-pair variability in these responses in MZ than in DZ twin pairs. The heritability estimate was 0.39 (P = 0.07) suggesting that host genetic factors contributed 39% of the variation. A better understanding of these genetic influences will contribute to the elucidation of preventive therapies for ocular C. trachomatis infection and may identify important mechanisms in protection for rational vaccine construction.

Field evaluation of the performance and testing costs of a rapid point-of-care test for syphilis in a red-light district of Manaus, Brazil.

OBJECTIVES: To assess the performance, usefulness and cost of a rapid treponemal antibody assay (VisiTect Syphilis) to detect syphilis in high risk populations. METHODS: People who attended STI clinics in Manaus, Brazil, were screened for syphilis using the fluorescent treponemal antibody absorption (FTA-Abs) test and a non-treponemal test (Venereal Diseases Research Laboratory (VDRL)), and for HIV. Finger prick blood samples were tested with VisiTect Syphilis. The rapid test was evaluated against the reference FTA-Abs and for its usefulness in detecting active syphilis (FTA-Abs and VDRL positive). Operational performance was assessed through providers' and patients' interviews. An economic evaluation was conducted from the provider's perspective. RESULTS: 510 patients (60% men) were enrolled, of whom 13 (2.5%) were HIV-1 seropositive. Syphilis prevalence (FTA-Abs) was 18% and active syphilis prevalence was 7.5%. 11% (57/506) of samples were positive by VisiTect. The sensitivity, specificity, positive and negative predictive values of VisiTect Syphilis were 57% (95% CI 45.8 to 66.7), 99% (95% CI 97.0 to 99.6), 91% (95% CI 80.0 to 96.7) and 91% (95% CI 88.0 to 93.5), respectively. VisiTect Syphilis identified 79% (30/38) of active syphilis cases. The cost per case of syphilis was $16.8 for VDRL, $33.2 for low cost and $56.3 for high cost VisiTect Syphilis; the cost per case of active syphilis was $21.3, $57.5 and $97.6, respectively. Patients identified finger prick pain and preference for venous blood collection as minor barriers to test use. CONCLUSION: VisiTect Syphilis had low sensitivity in field use and was less cost effective than conventional VDRL. However, rapid and correct identification of a high proportion of active syphilis cases combined with operational characteristics suggest a role in high risk populations.

Diagnostic tests for kala-azar: a multi-centre study of the freeze-dried DAT, rK39 strip test and KAtex in East Africa and the Indian subcontinent.

Three diagnostic tests for visceral leishmaniasis (VL), the freeze-dried direct agglutination test (FD-DAT), the rK39 dipstick and a urine latex antigen test (KAtex), were evaluated for use in primary care in East Africa and the Indian subcontinent. Clinical suspects were prospectively recruited and tissue, blood and urine samples were taken. Direct microscopic examination of tissue smear, and FD-DAT, rK39 and KAtex were performed. Sensitivity and specificity with 95% credible intervals were estimated using Bayesian latent class analysis. On the Indian subcontinent both the FD-DAT and the rK39 strip test exceeded the 95% sensitivity and 90% specificity target, but not so in East Africa. Sensitivity of the FD-DAT was high in Ethiopia and Kenya but lower in Sudan, while its specificity was below 90% in Kenya. Sensitivity of the rK39 was below 80% in the three countries, and its specificity was only 70% in Ethiopia. KAtex showed moderate to very low sensitivity in all countries. FD-DAT and rK39 can be recommended for clinical practice on the Indian subcontinent. In East Africa, their clinical use should be carefully monitored. More work is needed to improve existing formats, and to develop better VL diagnostics.

Spousal sexual violence and poverty are risk factors for sexually transmitted infections in women: a longitudinal study of women in Goa, India.

OBJECTIVES: To describe factors associated with incident sexually transmitted infections (STI) in a population-based sample of women in Goa, India. METHODS: A random sample of women aged 18-45 years was enrolled in Goa from November 2001 to May 2003. All subjects who consented to participate and completed the recruitment procedure were interviewed six and 12 months after recruitment. Incident chlamydia, gonorrhoea or trichomoniasis from vaginal and/or urine specimens were detected using a commercial polymerase chain reaction and the InPouch TV Culture Kit. RESULTS: Of the 2180 women followed up, 64 had an incident STI (incidence of 1.8% in the first six months, and 1.4% in the second six months). Incident STI was associated with low socioeconomic status, marital status, and with concurrent bacterial vaginosis. Incidence was highest among women who were married and exposed to sexual violence (10.9%), were concerned about their husbands' affairs (10.5%), or were separated, divorced or widowed women (11.0%). CONCLUSIONS: Socially disadvantaged women are at increased risk of STI in this population. Sexual intercourse outside marriage was rarely reported in this population, and women are at risk of becoming infected within marriage, especially those with sexual violence. This highlights the vulnerabilities of socially disadvantaged married women in India, and the need for healthcare professionals to screen STI patients for violence, and provide the necessary support. The results also stress the importance of effectively diagnosing and treating married men with STI and promoting safer sex within marriage.

Excellence in sexually transmitted infection (STI) diagnostics: recognition of past successes and strategies for the future.

Diagnostic advances do not generally receive the recognition given to prevention and treatment contributions, for the control and management of infectious diseases including sexually transmitted infections (STIs). In order to identify seminal diagnostic contributions over a half century (1950-2000), the Editorial Board of the WHO Sexually Transmitted Diseases Diagnostics Initiative (SDI) Publication Review or "electronic journal club" were asked to nominate their choices of peer-reviewed publications for special recognition. From 43 nominations, 13 were voted by a panel of 25 "experts" as having made the most significant contributions. The 1964 article by Thayer and Martin, which identified a selective media for gonococcal culture, was chosen unanimously by all panel members and is identified as the classic STI diagnostic article for this era.

Rapid tests for sexually transmitted infections (STIs): the way forward.

In the developing world, laboratory services for sexually transmitted infections (STIs) are either not available, or where limited services are available, patients may not be able to pay for or physically access those services. Despite the existence of national policy for antenatal screening to prevent congenital syphilis and substantial evidence that antenatal screening is cost-effective, implementation of syphilis screening programmes remains unacceptably low because of lack of screening tools that can be used in primary health care settings. The World Health Organization Sexually Transmitted Diseases Diagnostics Initiative (SDI) has developed the ASSURED criteria as a benchmark to decide if tests address disease control needs: Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free and Deliverable to end-users. Rapid syphilis tests that can be used with whole blood approach the ASSURED criteria and can now be deployed in areas where no previous screening has been possible. Although rapid tests for chlamydia and gonorrhoea lack sensitivity, more tests are in development. The way forward for STI diagnostics requires a continuing quest for ASSURED tests, the development of a road map for test introduction, sustainable programmes for quality assurance, and the creation of a robust infrastructure linked to HIV prevention that ensures sustainability of STI control efforts that includes viral STIs.

Disseminating sexually transmitted infections diagnostics information: the SDI web publication review series.

OBJECTIVES: The World Health Organization Sexually Transmitted Diseases Diagnostics Initiative (SDI) website publication review seeks to provide health care providers in all geographic and economic settings with timely, critical, and concise information concerning new developments in laboratory and field diagnosis of sexually transmitted infections (STI). METHODS: Since 2003, the website (www.who.int/std_diagnostics/literature_reviews) has disseminated information in the form of annotated abstracts and commentaries on articles covering studies of STI laboratory-based and rapid assays that are commercially available or under development. Articles identified through searches of PubMed, specific journals, and by referrals from Editorial Board members are selected for inclusion if they meet pre-specified criteria. The objectives, methods, results, and conclusions for each article are summarised and board members are invited to prepare commentaries addressing study design and applicability of findings to end users. RESULTS: Currently, 91 STI diagnostics experts from 17 countries on six continents serve on the Editorial Board. Twelve quarterly issues have been posted that include summaries of 214 original and 17 review articles published from January 2002 through March 2005, with expert commentaries on 153 articles. Interest in the site has increased every year. In 2005, over 36 700 unique visitors from more than 100 countries viewed over 75,000 pages of information. CONCLUSIONS: The SDI Publication Review series has the potential to contribute to SDI's goal of improving care for patients with STI by increasing knowledge and awareness of STI diagnostics. Given the proliferation of internet-based STI testing services, this website may be broadened to meet the needs of a wider range of users.

Diagnosis of gonococcal infection in high risk women using a rapid test.

OBJECTIVE: To assess the performance and acceptability for patients and health care workers of the NGThermo Biostar (GC OIA) to diagnose gonococcal infection compared with culture using modified Thayer Martin medium. METHODS: This study involved 326 high-risk women presenting with vaginal discharge or referral by sexual partner with urethral discharge at a sexually transmitted infections (STI) clinic in Manaus, Brazil. Endocervical swabs collected from the women were tested with both the NG Biostar and modified Thayer Martin culture as the reference standard test. Clinic staff were trained to perform the NG Biostar on site and the culture was performed in the laboratory of the clinic. RESULTS: The prevalence of gonococcal infection as measured by the reference standard was 15% (50/326) overall. Among asymptomatic participants, the prevalence of infection was 17.7% (25/141) and among symptomatic women it was 13.5% (25/185) (p = 0.3). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the NG Biostar test, with 95% confidence intervals (CI), were 60% (46.4% to 73.6%), 89.9% (86.2% to 93.6%), 55.6% (42.4% to 68.8%), and 92.6% (89.5% to 95.7%), respectively; 98.8% of study participants were willing to wait approximately 1 hour in the clinic for test results. CONCLUSION: Syndromic management protocols for treatment of STI in developing countries require refinement because, as currently described, they lead to over-treatment of cervical infection. A rapid test done during patients' initial presentation and leading to immediate treatment if positive would help improve the accuracy of diagnosis and could also be used to screen asymptomatic women. Even though the NG Biostar had a low sensitivity and PPV, which is less than ideal, it could still improve the rates of treatment over the gold standard test that requires return visits for patients to receive results and to benefit from treatment. Cost-effectiveness studies using rapid point-of-care tests for Neisseria gonorrhoeae infection compared to the syndromic approach should be carried out to assess their value in STI diagnosis and treatment in developing nations.

A multi-centre evaluation of nine rapid, point-of-care syphilis tests using archived sera.

OBJECTIVES: To evaluate nine rapid syphilis tests at eight geographically diverse laboratory sites for their performance and operational characteristics. METHODS: Tests were compared "head to head" using locally assembled panels of 100 archived (50 positive and 50 negative) sera at each site using as reference standards the Treponema pallidum haemagglutination or the T pallidum particle agglutination test. In addition inter-site variation, result stability, test reproducibility and test operational characteristics were assessed. RESULTS: All nine tests gave good performance relative to the reference standard with sensitivities ranging from 84.5-97.7% and specificities from 84.5-98%. Result stability was variable if result reading was delayed past the recommended period. All the tests were found to be easy to use, especially the lateral flow tests. CONCLUSIONS: All the tests evaluated have acceptable performance characteristics and could make an impact on the control of syphilis. Tests that can use whole blood and do not require refrigeration were selected for further evaluation in field settings.

Clinic-based evaluation of Clearview Chlamydia MF for detection of Chlamydia trachomatis in vaginal and cervical specimens from women at high risk in China.

OBJECTIVES: To determine the performance of a rapid Chlamydia trachomatis (CT) test (Clearview Chlamydia MF) compared to the current "gold standard" (Roche Amplicor CT assay) test, and to assess acceptability of the tests to patients. METHODS: A total of 1497 women at sexually transmitted diseases (STD) clinics or re-education centres in six urban cities (Shanghai, Nanjing, Shenzhen, Guangzhou, Chengdu and Fuzhou) in China participated in the study. Three vaginal and three cervical swabs were collected from each participant. Rapid CT tests were performed locally on the first vaginal and cervical swabs and the results were read independently by two staff members. The second and third swabs were randomised for performing the Roche CT assay at the National STD Reference Laboratory. Acceptability of the rapid tests to patients was determined by asking patients in clinics about their willingness to wait for the results. RESULTS: The prevalence of CT was 13.2% (197/1497), as determined by the Roche assay with cervical specimens. CT was detected in 78 vaginal and 127 cervical specimens by the rapid test and the positive rates determined with cervical specimens were significantly higher than those with vaginal specimens (p<0.001). There was good agreement between the results read by two independent staff for either vaginal or cervical specimens (both kappa = 0.98, p<0.001). Sensitivities for vaginal and cervical specimens were 32.8% and 49.7%, respectively, and specificities were 99.2% and 97.9%, respectively. The positive predictive value was 85.7% for vaginal and 78.4% for cervical specimens. The vast majority of the patients (99.1%) were willing to wait up to two hours for the results. CONCLUSION: Clearview Chlamydia MF, while yielding a rapid result and requiring minimal laboratory facilities, had unacceptably low sensitivity compared to a nucleic acid amplification test. Rapid tests yielding results within one hour are generally accepted by the clients.

Modelling the cost effectiveness of rapid point of care diagnostic tests for the control of HIV and other sexually transmitted infections among female sex workers.

BACKGROUND: In sub-Saharan Africa, gonococcal and chlamydial infections are usually managed using the syndromic approach. However, many infections are asymptomatic in women, and the syndromic algorithm has poor sensitivity and specificity for infections caused by Neisseria gonorrhoeae (Ng) and Chlamydia trachomatis (Ct). Because of this, rapid point of care (POC) tests for Ct/Ng could improve sexually transmitted infection (STI) management in women. This study uses mathematical modelling to estimate the incremental cost effectiveness of using POC tests to diagnose Ng/Ct instead of the current syndromic approach used by the SIDA2 HIV/STI prevention project for female sex workers in Cotonou, Benin. METHODS: A dynamic mathematical model was used with data from Cotonou to estimate the HIV impact of the existing SIDA2 project (1995-8), and to project how impact would change if POC tests had been used. As observed in test evaluations, the POC tests were assumed to have high specificity, but a range of sensitivities. The incremental economic cost effectiveness of using POC tests was modelled using data on intervention costs and an evaluation of an Ng POC test in Cotonou in 2004. All costs were in 2004 US dollars. RESULTS: The model estimated the STI treatment aspect of the intervention averted 18 553 Ng/Ct and 359 HIV infections over 4 years when the syndromic approach was used. In contrast, if Ng/Ct had been diagnosed with a 70-80% sensitive and 95% specific POC test then 24-31% fewer clinic attenders would have been treated, 40-60% more Ng/Ct and HIV infections would have been averted, and the incremental cost effectiveness of using them would have been 107-151 dollars per HIV infection averted if the POC tests cost 2 dollars and 58-81 dollars if they cost 1 dollar. CONCLUSIONS: POC tests can be a cost effective strategy for substantially increasing the impact on HIV transmission, and decreasing the degree of inappropriate treatment of STI treatment interventions that use syndromic management to diagnose Ng/Ct.

Risk factors associated with pelvic inflammatory disease.

OBJECTIVE: To investigate factors associated with pelvic inflammatory disease (PID). METHODS: A case-control study was used to investigate demographic and behavioural factors, and causative agents associated with PID. RESULTS: A total of 381 participants were recruited: 140 patients, and 105 and 136 controls in tubal ligation and general practice groups, respectively. When compared with a PID-free tubal ligation control group, increased risk of PID was associated with: age <25 years; age at first sexual intercourse <20 years; non-white ethnicity; not having had children; a self-reported history of a sexually transmitted disease; and exposure to Chlamydia trachomatis. When compared with a general practice control group, increased risk was associated with: age <25 years; age at first sexual intercourse <15 years; lower socioeconomic status; being single; adverse pregnancy outcome; a self-reported history of a sexually transmitted disease; and exposure to C trachomatis. Of the cases, 64% were not associated with any of the infectious agents measured in this study (idiopathic). CONCLUSIONS: A high proportion of cases were idiopathic. PID control strategies, which currently focus on chlamydial screening, have to be reviewed so that they can prevent all cases of PID. Behavioural change is a key factor in the primary prevention of PID, and potential modifiable risk factors were associated with PID.