A review of recent advances in rapid point-of-care tests for syphilis

A Scoping Review of Supply Chain Management Systems for Point of Care Diagnostic Services: Optimising COVID-19 Testing Capacity in Resource-Limited Settings

Background: Point of care (POC) testing has enabled rapid coronavirus disease 2019 (COVID-19) diagnosis in resource-limited settings with limited laboratory infrastructure and high disease burden. However, the accessibility of the tests is not optimal in these settings. This scoping review mapped evidence on supply chain management (SCM) systems for POC diagnostic services to reveal evidence that can help guide future research and inform the improved implementation of SARS-CoV-2 POC diagnostics in resource-limited settings. Methodology: This scoping review was guided by an adapted version of the Arksey and O’Malley methodological framework. We searched the following electronic databases: Medline Ovid, Medline EBSCO, Scopus, PubMed, PsychInfo, Web of Science and EBSCOHost. We also searched grey literature in the form of dissertations/theses, conference proceedings, websites of international organisations such as the World Health Organisation and government reports. A search summary table was used to test the efficacy of the search strategy. The quality of the included studies was appraised using the mixed method appraisal tool (MMAT) version 2018. Results: We retrieved 1206 articles (databases n = 1192, grey literature n = 14). Of these, 31 articles were included following abstract and full-text screening. Fifteen were primary studies conducted in LMICs, and 16 were reviews. The following themes emerged from the included articles: availability and accessibility of POC diagnostic services; reasons for stockouts of POC diagnostic tests (procurement, storage, distribution, inventory management and quality assurance) and human resources capacity in POC diagnostic services. Of the 31 eligible articles, 15 underwent methodological quality appraisal with scores between 90% and 100%. Conclusions: Our findings revealed limited published research on SCM systems for POC diagnostic services globally. We recommend primary studies aimed at investigating the barriers and enablers of SCM systems for POC diagnostic services for highly infectious pathogens such SARS-CoV-2 in high disease-burdened settings with limited laboratory infrastructures.

Clinical Presentation of Incident Syphilis Among Men Who Have Sex with Men Taking HIV Pre-Exposure Prophylaxis in Melbourne, Australia

BACKGROUND

Current international guidelines on human immunodeficieny virus (HIV) Pre-Exposure Prophylaxis (PrEP) recommend serological screening for syphilis at routine 3-monthly PrEP appointments. The aim of our study was to describe the pattern of clinical presentation of syphilis among men who have sex with men (MSM) taking PrEP. We were interested in whether syphilis is detected through screening at scheduled3-monthly PrEP clinic appointments or whether primary or secondary syphilis presented at unscheduled interval visits.

METHODS

This was a retrospective study of MSM attending the PrEP clinic at the Melbourne Sexual Health Centre between February 2016 and March 2019. Serological screening for syphilis was routinely undertaken at 3-monthly PrEP clinic appointments. Diagnoses of early syphilis were identified from PrEP clinic visits and from interim walk-in STI clinic attendances.

RESULTS

There were 69 cases of early syphilis among 61 MSM taking PrEP during the study period. There were 24 (35%) primary, 16 (23%) secondary, and 29 (42%) early latent infections. The incidence of early syphilis was 8.6 per 100 person-years. A substantial proportion of primary (58%) and secondary (44%) syphilis diagnoses were made at interim STI clinic attendances, between PrEP appointments.

CONCLUSIONS

Syphilis screening at routine 3-monthly PrEP visits alone fails to detect a proportion of primary and secondary syphilis infections and may be insufficient in preventing onward transmission. Education of MSM taking PrEP regarding the risk of syphilis and symptom recognition is necessary together with access to syphilis testing between PrEP visits.

Serological Markers for Syphilis Among Persons Presenting With Syndromes Associated With Sexually Transmitted Infections: Results From the Zimbabwe STI Etiology Study

BACKGROUND

Syphilis prevalence in sub-Saharan Africa appears to be stable or declining but is still the highest globally. Ongoing sentinel surveillance in high-risk populations is necessary to inform management and detect changes in syphilis trends. We assessed serological syphilis markers among persons with sexually transmitted infections in Zimbabwe.

METHODS

We studied a predominantly urban, regionally diverse group of women and men presenting with genital ulcer disease (GUD), women with vaginal discharge and men with urethral discharge at clinics in Zimbabwe. Syphilis tests included rapid plasma reagin and the Treponema pallidum hemagglutination assay.

RESULTS

Among 436 evaluable study participants, 36 (8.3%) tested positive for both rapid plasma reagin and Treponema pallidum hemagglutination assay: women with GUD: 19.2%, men with GUD: 12.6%, women with vaginal discharge: 5.7% and men with urethral discharge: 1.5% (P < 0.0001).

CONCLUSIONS

Syphilis rates in Zimbabwe are high in sentinel populations, especially men and women with GUD.

Rapid Syphilis Testing for Men Who Have Sex With Men in Outreach Settings: Evaluation of Test Performance and Impact on Time to Treatment

BACKGROUND

Rapid syphilis tests (RST) may shorten time to syphilis diagnosis and treatment while enhancing access to testing in outreach settings. There are limited data on the performance of RST in outreach settings in the US.

METHODS

We offered RST (Syphilis Health Check) at 6 outreach sites to men who reported having sex with men and no prior history of syphilis. Clients accepting RST were also tested with laboratory-based rapid plasma reagin (RPR) and reflex Treponema pallidum particle agglutination (TPPA) assay when RPR or RST were positive. Clients with positive RST were immediately referred to a sexually transmitted infection clinic. Those declining RST were screened with RPR and reflex TPPA only. The validity of the RST-based algorithm was compared with the RPR-based algorithm among participants receiving both. Time to treatment for those accepting RST was compared with those declining RST and to a historical control group screened in outreach settings with RPR and reflex TPPA before the availability of RST.

RESULTS

Rapid syphilis test was accepted by 690 (64%) of 1081 eligible clients. Compared with RPR-based algorithm, RST sensitivity was 90%; specificity, 98.5%; positive predictive value, 47.4%; and negative predictive value, 98.5. The single false-negative case by RST was determined to be a late latent case by RPR/TPPA. Median time to treatment was 1 day (range, 0-6 days) for 9 of 690 accepting RST, compared to 9 days (range, 7-13 days) for 3 of 391 declining RST, and 9 days (range, 6-21 days) for 25 of 1229 historical controls (P < 0.0001).

CONCLUSION

Compared with an RPR-based algorithm, RST identified all early syphilis cases. Although RST had high specificity and negative predictive value, the low positive predictive value resulted in additional assessments in a sexually transmitted infection clinic for some patients. However, RST use in outreach settings significantly decreased time to treatment for new syphilis cases.

Use of Oral Fluid With a Rapid Treponemal Test for Syphilis Evaluation

We aimed to determine if rapid treponemal tests intended for whole-blood specimens could be used to detect treponemal antibody in oral fluid. We found a high sensitivity of oral fluid rapid testing, which increased with increasing rapid plasma reagin titer, suggesting potential for the development of accurate rapid oral syphilis tests.

Supply chain management and accessibility to point-of-care testing in resource-limited settings: a systematic scoping review

BACKGROUND

World Health Organization (WHO) has created an essential list of in-vitro diagnostics. Supply chain management (SCM) is said to be the vehicle that ensures that developed point-of-care (POC) tests reach their targeted settings for use. We therefore, mapped evidence on SCM of and accessibility to POC testing (availability and use of POC tests) in low- and middle-income countries (LMICs).

METHODS

We conducted a systematic scoping review using Arksey and O'Malley's framework as a guide. We searched PubMed; CINAHL; MEDLINE; WEB of Science; Science Direct; and Google Scholar databases for studies that focused on POC diagnostic tests and SCM. The review included studies that were undertaken in 140 countries defined by the World Bank as LMICs published up to August 2017. Two reviewers independently screened the abstracts and full articles against the eligibility criteria. The study used the mixed methods appraisal tool version 2011 to assess the risk of bias for the included studies. NVivo version 11 was employed to extract themes from all included studies and results presented using a narrative approach.

RESULTS

Of 292 studies identified in this review, only 15 published between 2009 and 2017 included evidence on POC diagnostics and SCM. Of the 15 studies, three were conducted in Zambia, one each in Mozambique, Uganda, Guatemala; South Africa, one in Burkina Faso, Zimbabwe, and one multi-country study (Tanzania, Uganda, China, Peru and Zambia and Brazil). Six studies were not country specific since they were not primary studies. Majority of the studies reported stock-outs of HIV, syphilis, and malaria POC tests. There was a moderate to substantial level of agreement between the reviewers' responses at full article screening stage (Kappa statistic = 0.80, p < 0.01). Nine studies underwent methodological quality appraisal and all, scored between 90 and 100%.

CONCLUSIONS

The results demonstrated limited published research on SCM of and accessibility to POC testing in LMICs. Further studies aimed at investigating SCM of POC tests in resource-limited settings to identify the barriers/challenges and provide a context-specific evidence-based solutions for policy/decision makers, implementers, and POC developers, funders, and development partners would be essential.

PROSPERO REGISTRATION NUMBER

CRD42016043711.

Will an innovative connected AideSmart! app-based multiplex, point-of-care screening strategy for HIV and related coinfections affect timely quality antenatal screening of rural Indian women? Results from a cross-sectional study in India

Objectives

In rural pregnant Indian women, multiple missed antenatal screening opportunities due to inadequate public health facility-based screening result in undiagnosed HIV and sexually transmitted bloodborne infections (STBBIs) and conditions (anaemia). Untreated infections complicate pregnancy management, precipitate adverse outcomes and risk mother-to-child transmission. Additionally, a shortage of trained doctors, rural women’s preference for home delivery and health illiteracy affect health service delivery. To address these issues, we developed AideSmart!, an innovative, app-based, cloud-connected, rapid screening strategy that offers multiplex screening for STBBIs and anaemia at the point of care. It offers connectivity, integration, expedited communications and linkages to clinical care throughout pregnancy.

Methods

In a cross-sectional study, we evaluated the AideSmart! strategy for feasibility, acceptability, preference and impact. We trained 15 healthcare professionals (HCPs) to offer the AideSmart! strategy to 510 pregnant women presenting for care to outreach rural service units of Christian Medical College, Vellore, India.

Results

With the AideSmart! screening strategy, we recorded an acceptability of 100% (510/510), feasibility (completion rate) of 91.6% (466/510) and preference of 73%. We detected 239 infections/conditions (239/510, 46.8%) at the point-of-care, of which 168 (168/239; 70%) were lab confirmed, staged and treated rapidly. Of the 168 confirmed infections/conditions, 127 were anaemia, 11 Trichomonas and 30 hepatitis B virus (HBV) (25 resolved naturally, 5 active infections). Four infants (4/5; 80%) were prophylaxed for HBV and were declared disease-free at 9 months. Recruited participants were young; mean age was 24 years (range: 17–40) and 74% (376/510) were in their second trimester. Furthermore, 95% of the participants were retained throughout their pregnancy.

Conclusion

The AideSmart! strategy was deemed feasible to operationalise by HCPs. It was accepted and preferred by participants, resulting in timely screening and treatment of HIV/STIs and anaemia, preventing mother-to-child transmission. The strategy could be reverse-innovated to any context to maximise its health impact.

Gene subtype analysis of Treponema pallidum for drug resistance to azithromycin

Azithromycin has been widely used for the treatment of Treponema pallidum. However, the drug resistance of T. pallidum for azithromycin is currently increasing. The aim of the present study was to analyze the association between gene subtypes of T. pallidum and drug resistance for azithromycin. The gene subtypes of T. pallidum were assayed by a polymerase chain reaction technique. Drug resistance of T. pallidum was analyzed using an antimicrobial susceptibility test. The results demonstrated that gene type tpr presented higher drug resistance compared with arp and tp0548 gene types of T. pallidum. Gene type tpr was identified as eight gene subtypes (14a/f, 14e/f, 12e/f, 12d/f, 6d/f, 11d/f, 14j/f and 8d/f) among 324 cases. It was identified that 23S rRNA A2058G mutation was observed in gene subtypes 14a/f, 14e/f and 12e/f. A2059G mutation occurred in the gene subtypes 8d/f, 12d/f, 6d/f, 11d/f and 14j/f. The proportions of azithromycin-resistant genotypes harboring either the A2058G or the A2059G mutation among the T. pallidum strains were 34.2 and 65.8%, respectively. The antimicrobial susceptibility test demonstrated that A2059G mutations exhibited a higher drug resistance for azithromycin compared with A2058G mutations. In conclusion, these results indicate that azithromycin resistance in T. pallidum is associated with gene subtype, which may contribute to the treatment of T. pallidum.

Attributes of diagnostic tests to increase uptake of dual testing for syphilis and HIV in Port-au-Prince, Haiti

Introduction Syphilis and HIV screening is highly recommended for pregnant women and those at risk for infection. We used conjoint analysis to identify factors associated with testing preferences for HIV and syphilis infection. Methods We recruited 298 men and women 18 years and over seeking testing or care at GHESKIO (Haitian Study Group for Kaposi's Sarcoma and Opportunistic Infections) clinics. We created eight hypothetical dual HIV-syphilis test profiles varying across six dichotomous attributes. Participants were asked to rate each profile using Likert preference scales. An impact score was generated for each attribute by taking the difference between the preference scores for the preferred and non-preferred level of each attribute. Two-sided one-sample t-test was used to generate p values. Results Of 298 study participants, 61 (20.5%) were male. Of 237 females, 49 (20.7%) were pregnant. Cost (free vs. US$4; p < .0001) had the highest impact on willingness to test, followed by number of blood draws (1 vs. 2; p < .0001), blood draw method (fingerprick vs. venipuncture; p < .0001), test type (rapid vs. laboratory; p = .0005), and time-to-result (20 minutes vs. 1 week; p = .0139). Conclusion HIV and syphilis testing preferences for this study sample in Port-au-Prince prioritized cost, single fingerprick, laboratory-based testing and timeliness.

Laboratory medicine and mobile health technologies at crossroads: Perspectives for the management of chronic diseases

Management of chronic diseases represents a leading health and economic issue worldwide. Biomarkers are critical for the diagnosis and management of both communicable and non-communicable chronic diseases, and mobile health (mHealth) technologies are about to change the "game" with regard to the management of patients with such chronic diseases. The development of efficient, accurate and interactive solutions that integrate biomarkers and mHealth opens new perspectives for caregivers for the management of chronic illness.

Emerging trends and persistent challenges in the management of adult syphilis

There are an estimated 10.6 million incident cases of syphilis worldwide each year. We highlight some persistent challenges and emerging trends in the clinical management of syphilis with a particular focus on therapy, serology, diagnostics, and prevention. Decades after the introduction of penicillin, the optimal management of early syphilis continues to be a controversial topic, particularly in the setting of HIV co-infection. Similarly, the need for routine lumbar puncture in HIV co-infected asymptomatic persons is an unanswered question. Despite advances in both automation and point-of-care diagnostics, we continue to rely on indirect measures of disease activity to manage this infection. As syphilis rates in some populations continue to rise, novel and effective prevention strategies are needed.

Syphilis: a fresh look at an old foe

Syphilis remains a pressing public health problem globally across different populations including men who have sex with men and pregnant women. It is timely to review what international surveillance data tell us and the evidence behind public health interventions aimed at controlling syphilis. A reinvigorated response to the re-emergence of syphilis is required.