Field evaluation of Standard Diagnostics' Bioline HIV/Syphilis Duo test among female sex workers in Johannesburg, South Africa

Syphilis in Hematopathology Practice: A Diagnostic Challenge

CONTEXT.—

Syphilis, a reemerging disease caused by the spirochete Treponema pallidum, is becoming more frequent in surgical pathology and hematopathology practices. Hematopathologists typically receive lymph node biopsies from patients with syphilis who have localized or diffuse lymphadenopathy. Occasionally, syphilis infection in the aerodigestive tract can show a prominent lymphoplasmacytic infiltrate and mimic lymphoma. Besides the varying and occasional atypical morphology, the fact that clinical suspicion tends to be low or absent when histologic evaluation is requested adds to the importance of making this diagnosis.

OBJECTIVE.—

To summarize histologic features of syphilitic lymphadenitis and syphilis lesions in the aerodigestive tract, and to review differential diagnosis and potential diagnostic pitfalls.

DATA SOURCES.—

Literature review via PubMed search.

CONCLUSIONS.—

Characteristic histologic findings in syphilitic lymphadenitis include thickened capsule with plasma cell-rich inflammatory infiltrate, reactive follicular and paracortical hyperplasia with prominent lymphoplasmacytic infiltrate, and vasculitis. Lymph nodes, however, can show a number of other nonspecific histologic features, which frequently makes the diagnosis quite challenging. In the aerodigestive tract, syphilis is characterized by plasma cell-rich infiltrates. Immunohistochemistry for T pallidum is the preferred method for detecting spirochetes; however, this immunohistochemical stain shows cross-reactivity with other treponemal and commensal spirochetes. Differential diagnosis of syphilis in lymph nodes and the aerodigestive tract is broad and includes reactive, infectious, and neoplastic entities. Pathologists should be aware of the histologic features of syphilis and keep this challenging entity in the differential diagnosis.

Independent clinic-based evaluation of dual POCTs for screening for HIV and syphilis in men who have sex with men in Italy, Malta, Peru, and the United Kingdom

INTRODUCTION

Globally, the incidence of HIV and syphilis can be reduced by the use of validated point of care tests (POCTs). As part of the WHO PRoSPeRo Network, we aimed to evaluate the performance, acceptability, and operational characteristics of two dual HIV/syphilis POCTs (Bioline HIV/Syphilis Duo (Abbott) and DPP® HIV-Syphilis assay (Chembio) for the screening of HIV and syphilis amongst men who have sex with men (MSM).

METHOD AND ANALYSES

A cross sectional study of 2,577 MSM in Italy, Malta, Peru, and the United Kingdom (UK) presenting to seven clinic sites, were enrolled. Finger prick blood was collected to perform POCTs and results compared with standard laboratory investigations on venepuncture blood. Acceptability and operational characteristics were assessed using questionnaires. Diagnostic meta-analysis was used to combine data from the evaluation sites.

RESULTS

Based on laboratory tests, 23.46% (n = 598/2549) of participants were confirmed HIV positive, and 35.88% of participants (n = 901/2511) were positive on treponemal reference testing. Of all participants showing evidence of antibodies to Treponema pallidum, 50.56% (n = 455/900) were Rapid Plasma Reagin (RPR) test reactive. Of HIV positive individuals, 60.62% (n = 354/584) had evidence of antibodies to T. pallidum, and of these 60.45% (n = 214/354) exhibited reactive RPR tests indicating probable (co)infection. For Bioline POCT, pooled sensitivities and specificities for HIV were 98.95% and 99.89% respectively, and for syphilis were 73.79% and 99.57%. For Chembio pooled sensitivities and specificities for HIV were 98.66% and 99.55%, and for syphilis were 78.60% and 99.48%. Both tests can detect greater than 90% of probable active syphilis cases, as defined by reactive RPR and treponemal test results. These dual POCTs were preferred by 74.77% (n = 1,926) of participants, due to their convenience, and the operational characteristics made them acceptable to health care providers (HCPs).

CONCLUSIONS

Both the Bioline and the Chembio dual POCT for syphilis and HIV had acceptable performance, acceptability and operational characteristics amongst MSM in the PRoSPeRo network. These dual POCTs could serve as a strategic, more cost effective, patient and healthcare provider (HCP) friendly alternative to conventional testing; in clinical and other field settings, especially those in resource-limited settings.

Syphilis

Syphilis is a sexually and vertically transmitted bacterial infection caused by the bacterium Treponema pallidum. Its prevalence is high in low-income and middle-income countries, and its incidence has increased in high-income countries in the last few decades among men who have sex with men. Syphilis is a major cause of adverse pregnancy outcomes in low-income and middle-income countries. Clinical features include a primary chancre at the point of inoculation, followed weeks later by the rash of secondary syphilis, a latent period, and in some cases, involvement of the eyes, CNS, and cardiovascular systems. It is diagnosed serologically. A single intramuscular dose of long-acting benzathine penicillin is recommended for people who have had syphilis for less than 1 year and longer courses for people with late latent syphilis. Control strategies include screening and treatment of all pregnant women, and targeted interventions for groups at high risk. Vaccine development, research on antibiotic prophylaxis, and digital messaging as prevention strategies are ongoing.

Assessment of the Accuracy, Usability and Acceptability of a Rapid Test for the Simultaneous Diagnosis of Syphilis and HIV Infection in a Real-Life Scenario in the Amazon Region, Brazil

We field-assessed the accuracy, acceptability, and feasibility of the SD BIOLINE HIV/Syphilis Duo rapid diagnostic test in three groups: pregnant women, female sex workers (FSW), and men who have sex with men (MSM). Venous blood samples collected in the field were compared with the respective gold standard methods: SD BIOLINE HIV/Syphilis Duo Treponemal Test versus FTA-abs (Wama brand) treponemal laboratory test for syphilis, and SD BIOLINE HIV/Syphilis Duo Test versus the fourth generation Genscreen Ultra HIV Ag-Ag (Bio-Rad brand) laboratory test for HIV. From a total of 529 participants, 397 (75.1%) were pregnant women, 76 (14.3%) FSW and 56 (10.6%) MSM. Sensitivity and specificity parameters of HIV were 100.0% (95% CI: 82.35-100.0%) and 100.0% (95% CI: 99.28-100.0%), respectively. Sensitivity and specificity parameters found for TP antibody detection were 95.00% (95% CI: 87.69-98.62%) and 100.0% (95% CI: 98.18-100.0%), respectively. The SD BIOLINE HIV/Syphilis Duo Test showed high acceptability among participants (85.87%) and health professionals (85.51%), as well as easy usability by professionals (91.06%). The usability of the SD BIOLINE HIV/Syphilis Duo Test kit would not be a barrier to accessing rapid testing, if the product were incorporated into the list of health service supplies.

Diagnostic Accuracy of Rapid Point-of-Care Tests for Detecting Active Syphilis: A Systematic Review and Meta-Analysis

BACKGROUND

Syphilis represents an important cause of morbidity and mortality. Point-of-care (POC) test offers the advantages of diagnosing the condition and the possibility of starting treatment immediately.

METHODS

MEDLINE, Embase, CENTRAL, LILACS, World Health Organization International Clinical Trials Registry Platform, Web of Science, OpenGrey, and DARE were searched without language restrictions from inception to September 30, 2020. Diagnostic test accuracy studies that enrolled men and nonpregnant women of reproductive age under field conditions were analyzed. Only studies wherein all the patients had undergone a rapid POC test and those that included the reference standard (treponemal plus nontreponemal test) were eligible for inclusion. Studies were independently assessed for inclusion, data extraction, and bias risk. The data from these studies were extracted for meta-analyses. The quality of the evidence was assessed using the GRADE approach. Registration Prospero CRD42018107532.

RESULTS

Nine studies with 9666 participants were included. Nine POC brands were assessed. Sensitivities of the tests ranged from 0.67 to 1.00 and specificities from 0.93 to 1.00. The mean sensitivity and specificity of all the included studies was 0.86 (95% confidence interval, 0.79-0.91) and 0.98 (95% confidence interval, 0.96-0.99), respectively.

CONCLUSIONS

Based on the results of this systematic review, the POC test for syphilis showed good sensitivity and excellent specificity.

"I felt very small and embarrassed by the health care provider when I requested to be tested for syphilis": barriers and facilitators of regular syphilis and HIV testing among female sex workers in Uganda

Background

Periodic testing of female sex workers (FSW) for sexually transmitted infections (STIs) is a core component of global and national responses to achieve population-level STI elimination. We conducted a qualitative study to explore barriers and facilitators of regular syphilis and HIV testing among FSW in Uganda.

Methods

Within a quasi-experimental study among 436 FSW to assess the effect of peer education and text message reminders on uptake of regular STI and HIV testing among FSW, we conducted 48 qualitative interviews in four cities in Uganda from August–December 2018. We purposively selected FSW who tested for syphilis and HIV every 3–6 months; 12 FSW were interviewed in each city. Sex worker interviews explored: 1) reasons for periodic syphilis and HIV testing; 2) barriers and facilitators of testing; 3) experiences of testing; and 4) challenges faced while seeking testing services. Data were analyzed using thematic content analysis.

Results

Thematic analysis revealed individual- and health system-level barriers and facilitators of testing. For syphilis, barriers were a) interpersonal stigma, low perceived severity of syphilis and testing misconceptions (individual); and b) judgmental provider attitudes, paucity of facilities offering syphilis testing, stockouts of test kits and high cost (health system). Facilitators were c) desire to remain healthy, get married and have children, knowing the benefits of early treatment, influence of male partners/clients and normative testing behaviors (individual); and d) sex worker clinics offering dual syphilis/HIV testing (health system). For HIV, barriers included: a) internalized stigma (individual); and b) unfavorable clinic hours, stigma, discrimination, and unfriendly provider (health system). Facilitators were a) motivations to stay healthy and attract clients, habitual testing, self-efficacy, doubts about accuracy of negative test results, and use of post-exposure prophylaxis (individual); and d) availability of testing facilities (health system). Syphilis and HIV had similar testing barriers and facilitators.

Conclusions

HIV programs are likely to be important entry points for syphilis testing among FSW. Multi-level interventions to address testing barriers should consider focusing on these service delivery points. Extending the dual syphilis and HIV testing approach to FSW may improve testing uptake for both infections at public health facilities and decrease population-level incidence.

Acceptability of dual HIV/syphilis rapid test in community- and home-based testing strategy among transgender women in Buenos Aires, Argentina

BACKGROUND

Little is known of acceptability and feasibility of dual HIV and syphilis rapid tests in community- and home-based provider-initiated strategies among transgender women (TGW), in Latin America. Objectives were (1) to assess the acceptability of this strategy and, (2) to determine the percentage of positive results of HIV and syphilis, analyze the correlates of HIV or syphilis positive results, and measure the rates of effective referral and treatment completion among TGW.

METHODS

A multidisciplinary team tested 89 TGW in Buenos Aires. An acceptability survey was administered after the HIV/syphilis Duo test was used. All confirmed cases were referred for treatment initiation.

RESULTS

We found high levels of acceptability (98.8%) of this strategy among TGW. However, only 60.7% preferred simultaneous HIV and syphilis diagnosis test. Moreover, we found 9% of positive results of HIV, 51.7% of syphilis, and 3.4% of positive results for both infections. Only not being tested before was associated with an HIV positive result, and only low level of education was associated with a positive syphilis result. Among 8 TGW who tested positive for HIV, 37.5% (n = 3) started antiretroviral therapy. Of 46 who tested positive for syphilis, only 73.9% (n = 34) were effectively referred and from 23 who started treatment, only 39.1% completed it.

CONCLUSIONS

Community- and home-based dual HIV and syphilis rapid test is a feasible and highly acceptable approach for this hard-to-reach population. Implementing similar strategies could improve screening uptake and accessibility. However, these results highlight the need to improve strategies for treatment uptake, in order to reduce morbidity and risk of onward transmission.

The impact of antenatal syphilis point of care testing on pregnancy outcomes: A systematic review

Background

Mother-to-child transmission of syphilis remains a leading cause of neonatal death and stillbirth, disproportionally affecting women in low-resource settings where syphilis prevalence rates are high and testing rates low. Recently developed syphilis point-of-care tests (POCTs) are promising alternatives to conventional laboratory screening in low-resource settings as they do not require a laboratory setting, intensive technical training and yield results in 10–15 minutes thereby enabling both diagnosis and treatment in a single visit. Aim of this review was to provide clarity on the benefits of different POCTs and assess whether the implementation of syphilis POCTs is associated with decreased numbers of syphilis-related adverse pregnancy outcomes.

Methods

Following the PRISMA guidelines, three electronic databases (PubMed, Medline (Ovid), Cochrane) were systematically searched for intervention studies and cost-effectiveness analyses investigating the association between antenatal syphilis POCT and pregnancy outcomes such as congenital syphilis, low birth weight, prematurity, miscarriage, stillbirth as well as perinatal, fetal or infant death.

Results

Nine out of 278 initially identified articles were included, consisting of two clinical studies and seven modelling studies. Studies compared the effect on pregnancy outcomes of treponemal POCT, non-treponemal POCT and dual POCT to laboratory screening and no screening program. Based on the clinical studies, significantly higher testing and treatment rates, as well as a significant reduction (93%) in adverse pregnancy outcomes was reported for treponemal POCT compared to laboratory screening. Compared to no screening and laboratory screening, modelling studies assumed higher treatment rates for POCT and predicted the most prevented adverse pregnancy outcomes for treponemal POCT, followed by a dual treponemal and non-treponemal POCT strategy.

Conclusion

Implementation of treponemal POCT in low-resource settings increases syphilis testing and treatment rates and prevents the most syphilis-related adverse pregnancy outcomes compared to no screening, laboratory screening, non-treponemal POCT and dual POCT. Regarding the benefits of dual POCT, more research is needed. Overall, this review provides evidence on the contribution of treponemal POCT to healthier pregnancies and contributes greater clarity on the impact of diverse diagnostic methods available for the detection of syphilis.

Lifetime Syphilis Prevalence and Associated Risk Factors Among Female Prisoners in Brazil

BACKGROUND

In 2016, approximately 42,000 women were incarcerated in Brazil. The objectives of this study were to measure the lifetime prevalence of syphilis and sociodemographic and behavior correlates of antibody positivity among female prisoners in Brazil.

METHODS

We conducted a cross-sectional survey of 1327 incarcerated women in 2014 to 2015 sampled through a multistage cluster design to represent the penitentiary system throughout Brazil. A rapid treponemal antibody test approved by the Ministry of Health (Rapid Test DPP Sífilis Bio-Manguinhos) was used to detect lifetime history of infection. Analyses were adjusted using weights based on the inverse of the product of the probabilities of the sampling units at each stage of the design. Variables significantly associated with syphilis infection at P < 0.05 in multivariate analyses were retained in the final model.

RESULTS

Prevalence of syphilis antibody among female prisoners in Brazil was 11.6% (95% confidence interval [CI], 9.8%-13.8%). Higher syphilis prevalence was associated with black/Afro-Brazilian or mixed race/ethnicity (adjusted odds ratio [AOR], 1.78; 95% CI, 1.10-2.87), homelessness (AOR, 4.58; 95% CI, 2.78-7.56), abortion (AOR, 1.56; 95% CI, 1.02-2.38), and sexual violence (AOR, 1.59; 95% CI, 1.01-2.49). Syphilis prevalence was lower among women who had received condoms in school (AOR, 0.28; 95% CI, 0.08-1.00) as a marker for reproductive health education.

CONCLUSIONS

Women within the vast Brazilian prison system demonstrate a high lifetime cumulative incidence of syphilis. Our data advocate for increased screening and treatment of syphilis of incarcerated women and help identify women at higher risk within the prison system and within their communities of origin.

HIV and syphilis testing behaviors among heterosexual male and female sex workers in Uganda

Background

In Sub-Saharan Africa where HIV disproportionately affects women, heterosexual male sex workers (HMSW) and their female clients are at risk of acquiring or transmitting HIV and other STIs. However, few studies have described HIV and STI risk among HMSW. We aimed to assess and compare recent HIV and syphilis screening practices among HMSW and female sex workers (FSW) in Uganda.

Methods

Between August and December 2019, we conducted a cross-sectional study among 100 HMSW and 240 female sex workers (FSW). Participants were enrolled through snowball sampling, and an interviewer-administered questionnaire used to collect data on HIV and syphilis testing in the prior 12 and 6 months respectively. Integrated change model constructs were used to assess intentions, attitudes, social influences, norms and self-efficacy of 3-monthly Syphilis and 6-monthly HIV testing. Predictors of HIV and syphilis recent testing behaviors were estimated using negative binomial regression.

Results

We enrolled 340 sex workers of whom 100 (29%) were HMSW. The median age was 27 years [interquartile range (IQR) 25–30] for HMSW and 26 years [IQR], (23–29) for FSW. The median duration of sex work was 36 and 30 months for HMSW and FSW, respectively. HMSW were significantly less likely than FSW to have tested for HIV in the prior 12 months (50% vs. 86%; p = 0.001). For MSW, non-testing for HIV was associated with higher education [adjusted prevalence ratio (aPR) 1.66; 95% confidence interval (CI) 1.09–2.50], poor intention to seek HIV testing (aPR 1.64; 95% CI 1.35–2.04), perception that 6-monthly HIV testing was not normative (aPR 1.33; 95% CI 1.09–1.67) and low self-efficacy (aPR 1.41; 95% CI 1.12–1.79). Not testing for syphilis was associated with low intention to seek testing (aPR 3.13; 95% CI 2.13–4.55), low self-efficacy (aPR 2.56; 95% CI 1.35–4.76), negative testing attitudes (aPR 2.33; 95% CI 1.64–3.33), and perception that regular testing was not normative (aPR 1.59; 95% CI 1.14–2.22).

Conclusions

Non-testing for HIV and syphilis was common among HMSW relative to FSW. Future studies should evaluate strategies to increase testing uptake for this neglected sub-population of sex workers.

Performance of a Dual Human Immunodeficiency Virus/Syphilis Rapid Test Compared With Conventional Serological Testing for Syphilis and Human Immunodeficiency Virus in a Laboratory Setting: Results From the Zimbabwe STI Etiology Study

BACKGROUND

Dual human immunodeficiency virus (HIV)/syphilis rapid, point-of-care testing may enhance syphilis screening among high-risk populations, increase case finding, reduce time to treatment, and prevent complications. We assessed the laboratory-based performance of a rapid dual HIV/syphilis test using serum collected from patients enrolled in the Zimbabwe Sexually Transmitted Infections (STI) Etiology study.

METHODS

Blood specimens were collected from patients presenting with STI syndromes in 6, predominantly urban STI clinics in different regions of Zimbabwe. All specimens were tested at a central research laboratory using the Standard Diagnostics Bioline HIV/Syphilis Duo test. The treponemal syphilis component of the dual rapid test was compared with the Treponema pallidum hemagglutination assay (TPHA) as a gold standard comparator, both alone or in combination with a nontreponemal test, the rapid plasma reagin test. The HIV component of the dual test was compared with a combination of HIV rapid tests conducted at the research laboratory following the Zimbabwe national HIV testing algorithm.

RESULTS

Of 600 men and women enrolled in the study, 436 consented to serological syphilis and HIV testing and had specimens successfully tested by all assays. The treponemal component of the dual test had a sensitivity of 66.2% (95% confidence interval [CI], 55.2%-77.2%) and a specificity of 96.4% (95% CI, 94.5%-98.3%) when compared with TPHA; the sensitivity increased to 91.7% (95% CI, 82.6%-99.9%) when both TPHA and rapid plasma reagin were positive. The HIV component of the dual test had a sensitivity of 99.4% (95% CI, 98.4%-99.9%) and a specificity of 100% (95% CI, 99.9%-100%) when compared with the HIV testing algorithm.

CONCLUSIONS

Laboratory performance of the SD Bioline HIV/Syphilis Duo test was high for the HIV component of the test. Sensitivity of the treponemal component was lower than reported from most laboratory-based evaluations in the literature. However, sensitivity of the test increased substantially among patients more likely to have active syphilis for which results of both standard treponemal and nontreponemal tests were positive.

A community-based comprehensive intervention to reduce syphilis infection among low-fee female sex workers in China: a matched-pair, community-based randomized study

Background

Low-fee female sex workers (FSWs) are at high risk of acquiring and spreading human immunodeficiency virus (HIV)/sexually transmitted diseases (STDs) in China. There is an urgent need to develop comprehensive intervention measures targeted towards low-fee FSWs to reduce HIV/STD infections. Thus, this study aimed to reduce HIV/STD infections among low-fee FSW through a matched-pair, community-based randomized intervention trial carried out in 12 cities in three provinces in China.

Methods

Four cities from Guangxi Zhuang Autonomous Region, four from Yunnan Province, and four from Hunan Province were paired and participants received either the intervention package (including condom promotion, HIV and syphilis testing, reimbursement for syphilis treatment costs, and free anti-retroviral therapy or the current standard of care. Venue-based, convenience sampling was used to recruit FSWs. A face-to-face interview and HIV and syphilis blood testing was conducted at baseline and follow-up intervals of 24 months. Generalized linear mixed models (GLMM) were used to evaluate the effect of the intervention package on reducing HIV/STD infection in the FSWs.

Results

A total of 1024 eligible FSWs were enrolled in the baseline survey and 843 in the follow-up. GLMM results showed that syphilis infection was reduced by 49% in the intervention group compared to the current standard of care group (P = 0.0378, OR = 0.51, 95% CI: 0.27–0.96). FSWs aged 35 years or older were 2.38 times more likely to get syphilis infection compared to those younger than 35 years old (P <  0.0001, OR = 2.38, 95% CI: 1.55–3.65). The risk of syphilis infection among more educated FSWs was 0.43 times less than those with lower levels of education (P <  0.05, OR = 0.43, 95% CI: 0.63–0.93).

Conclusions

This study demonstrates that comprehensive interventions can lead to significant declines in syphilis infection amongst low-tier FSWs. Integrating both behavioral and biomedical intervention measures should be considered when developing programs for low-fee FSWs.

Trial registration

CHiCTR-TRC-12002655.

Low prevalence of syphilis infection among key populations in Togo in 2017: a national cross-sectional survey

Background

The World Health Organisation (WHO) recommends the screening of syphilis among populations highly exposed to HIV. However, data on the prevalence of syphilis in these populations are scarce in Togo. This study aimed at estimating the prevalence of syphilis among males who have sex with males (MSM), female sex workers (FSW) and drug users (DU) in Togo.

Methods

A cross-sectional bio-behavioral study was conducted in August and September 2017 using a respondent-driven sampling (RDS) method in eight major cities in Togo. A standardized questionnaire was used to record socio-demographic data and sexual behavior patterns. A blood sample was taken and SD Bioline Duo VIH/Syphilis rapid test was used to test for HIV and syphilis.

Results

A total of 2158 key populations (678 MSM, 1003 FSW and 477 DU), with an average age of 27.6 years (standard deviation 8.8 years) participated in the study. Prevalence of syphilis was 0.6% (95% CI = [0.3–1.0]) with no statistical significance between the three groups: null among MSM, 0.8% among FSW (95% CI = [0.37–1.63]) and 1.1% among DU (95% CI = [0.39–2.57]). There was no relation between HIV status and syphilis (p = 0.236). Among the 298 HIV-positive people, none was diagnosed with syphilis.

Conclusions

Findings from this study reveal a low prevalence rate of syphilis among key populations in Togo. Specific interventions into HIV prevention programs should be reinforced to eliminate syphilis in Togo.

Sífilis: a grande imitadora

A Sífilis é uma doença de transmissão vertical ou sexual causada por uma bactéria espiroqueta anaeróbia restrita que parasita exclusivamente o homem. Esse termo foi usado pela primeira vez em 1530 mas só em 1905 foi associado ao Treponema. Desde o advento da penicilina, os casos de sífilis decresceram até que há cerca de 20 anos a incidência dessa doença voltou a aumentar. Apesar de ser uma doença com múltiplas manifestações sendo capaz de mimetizar outras comorbidades o diagnóstico e tratamento do Lues é relativamente simples e barato o que vai de encontro a elevada prevalência dessa doença até os dias de hoje. Devido às mudanças epidemiológicas caracterizadas por aumento na incidência e prevalência na última década, o objetivo desta revisão foi apresentar os aspectos relevantes para detecção da doença e aspectos do seu tratamento, levando em conta as diferentes faces da doença, prevenção e tratamento.

Laboratory assessment of SD Bioline HIV/Syphilis Duo Kit among pregnant women attending antenatal clinic Mayuge Health Center III, East central Uganda

OBJECTIVE

Efforts to dual eradication of mother-to-child transmission of human immune deficiency virus (HIV) and syphilis have improved in the previous decades. This has however been hindered by limited validation studies. A cross-sectional study was conducted among adult pregnant women attending antenatal care clinic at Mayuge Health Center III. Two milliliters of venous blood were collected into Ethylene di-amine tetra acetic acid vacutainers, and tested for HIV and syphilis using the SD Bioline HIV/Syphilis Duo assay, and the national HIV and syphilis testing algorithm. Sensitivity and specificity were calculated for the Duo Kit against the gold standards within 95% confidence intervals.

RESULTS

Three hundred and eighty-two (382) participants were enrolled. Their mean age was 25.8 years. The prevalence of HIV was 1.8% (95% confidence interval 1.23-2.41); while that of syphilis was 2.1% (95% confidence interval 1.81-2.54), and the dual infection was 0.52% (95% confidence interval 0.37-0.92). The sensitivity and specificity of the SD Bioline HIV/Syphilis Duo assay were all 100.0% (95% confidence interval 99.5 to 100.0 and 98.6 to 100.0, respectively). The performance of the SD Bioline HIV/Syphilis Duo Kit was optimal, reassuring its aptness for use, and favorable qualities to a limited resource setting.

Field evaluation of a dual rapid Human Immunodeficiency Virus and treponemal syphilis rapid test in community-based clinics in Los Angeles and New York

INTRODUCTION

Dual human immunodeficiency virus/syphilis rapid diagnostic devices can play an important role in prevention efforts. The field performance of the INSTI Multiplex HIV-1/HIV-2/Syphilis Antibody Test (Multiplex) was evaluated.

METHODS

Fingerstick whole blood was tested using the rapid test. A fourth-generation HIV laboratory assay and treponemal-specific laboratory assays were used as reference. Rapid plasma reagin (RPR) was used to stratify treponemal results. Sensitivity and specificity were calculated.

RESULTS

Overall, 274 patients participated. Sensitivity of the Multiplex for detection of HIV was 98.8% (95% CI, 93.4-100%), and specificity was 100% (95% CI, 98.1-100%). Sensitivity for detection of syphilis antibodies was 56.8% (95% CI, 44.7-68.2%), and specificity was 98.5% (95% CI, 95.7-99.7%). Sensitivity for treponemal antibodies improved with increasing RPR and was 100% (95% CI, 78.2-100%) among samples with RPR titers ≥1:8.

CONCLUSIONS

The Multiplex showed excellent performance for detection of HIV antibodies and increasing sensitivity for detection of treponemal antibody with increasing RPR titer.

Laboratory evaluation of four HIV/syphilis rapid diagnostic tests

Background

Sexually transmitted infections, such as HIV and syphilis, are one of the major health care problems worldwide, especially in low- and middle income countries. HIV screening programmes have been widely used for many years. The introduction of rapid point-of-care tests (RDTs) that can detect both HIV and syphilis, using one single blood specimen, would be a promising tool to integrate the detection of syphilis into HIV programmes and so improve the accessibility of syphilis testing and treatment.

Methods

As part of the World Health Organization pre-qualification of in vitro diagnostics assessment, the laboratory performance of four dual HIV-Syphilis rapid diagnostic tests (SD Bioline HIV/Syphilis Duo, DPP HIV-Syphilis Assay, Multiplo Rapid TP/HIV Antibody Test and Insti Multiplex HIV-1/HIV-2/Syphilis Antibody Test) was assessed using a well characterized multiregional panel of stored sera specimens.

Results

In total 400 specimens were tested with each assay, resulting in excellent sensitivities and specificities for HIV, ranging from 99.5 to 100% and from 93.5 to 99.5%, respectively. Results obtained for the Treponema pallidum antibodies were lower, with the lowest sensitivity of 73.5% for Multiplo and the highest of 87% for SD Bioline. Specificities ranged from 99.0 to 100%.

Conclusion

Although these results suggest that the tests could further improve in accuracy in detection of treponemal antibodies, their introduction into screening programmes to increase the accessibility of HIV/Syphilis diagnosis and treatment for difficult to reach populations in the world is promising.

Field performance evaluation of dual rapid HIV and syphilis tests in three antenatal care clinics in Zambia

This cross-sectional study of 3212 pregnant women assessed the field performance, acceptability, and feasibility of two dual HIV/syphilis rapid diagnostic tests, the Chembio DPP HIV-syphilis Assay and the SD Bioline HIV/syphilis Duo in antenatal clinics. Sensitivity and specificity for HIV and syphilis were calculated compared to the rapid Determine HIV-1/2 with Uni-Gold to confirm positive results for HIV and the Treponema pallidum particle agglutination assay for syphilis. RPR titers ≥1:4 were used to define active syphilis detection. Acceptability and feasibility were assessed using self-reported questionnaires. For Chembio, the HIV sensitivity was 90.6% (95%CI = 87.4, 93.0) and specificity was 97.2% (95%CI = 96.2, 97.8); syphilis sensitivity was 68.6% (95%CI = 61.9, 74.6) and specificity was 98.5% (95%CI = 97.8, 98.9). For SD Bioline, HIV sensitivity was 89.4% (95%CI = 86.1, 92.0) and specificity was 96.3% (95%CI = 95.3, 97.1); syphilis sensitivity was 66.2% (95%CI = 59.4, 72.4) and specificity was 97.2% (95%CI = 96.4, 97.9). Using the reference for active syphilis, syphilis sensitivity was 84.7% (95%CI = 76.1, 90.6) for Chembio and 81.6% (95%CI = 72.7, 88.1) for SD Bioline. Both rapid diagnostic tests were assessed as highly acceptable and feasible. In a field setting, the performance of both rapid diagnostic tests was comparable to other published field evaluations and each was rated highly acceptable and feasible. These findings can be used to guide further research and proposed scale up in antenatal clinic settings.

A field evaluation of a rapid dual immunoassay for human immunodeficiency virus and syphilis antibodies, Hanoi, Vietnam

The SD BIOLINE HIV/Syphilis Duo (SD BIOLINE DUO) rapid test is a dual rapid lateral flow immunoassay that detects antibodies to both human immunodeficiency virus (HIV) and Treponema pallidum (TP) 'syphilis' via fingerprick whole blood. We evaluated the field performance of the SD BIOLINE HIV/Syphilis Duo test among two populations in Hanoi, Vietnam - men who have sex with men (MSM) and pregnant women. We also surveyed factors that influence participants' willingness to test for HIV and syphilis. This test has the potential to increase HIV and syphilis screening in low-resource settings. Patients who received healthcare services at a sexual health clinic for MSM and a district antenatal care center in Hanoi, Vietnam were recruited for the study. Participants with HIV and syphilis were intentionally recruited for adequate test performance evaluation via convenience sampling. At each facility, venipuncture blood specimens were obtained for reference testing for HIV and TP using SD BIOLINE HIV 1/2 3.0 and TP particle agglutination, respectively. SD BIOLINE DUO was compared to the standard reference tests and sensitivity and specificity were calculated. We calculated 95% confidence interval (CI) using the exact binomial method. We used conjoint analysis to identify test attributes that are associated with participant likelihood to seek HIV and syphilis testing. Of 280 participants, 100 (35.7%) were MSM and 180 (64.3%) were pregnant women. Of MSM, 17 (17.0%) were HIV positive and 49 (49.0%) were TP seropositive. All women were negative for both HIV and syphilis antibodies. For HIV antibody testing, sensitivity and specificity were 100.0% (95% CI: 80.5-100.0%) and 100.0% (95% CI: 98.6-100.0%), respectively. For the syphilis antibody testing, sensitivity and specificity were 83.1% (95% CI: 71.0-91.6%) and 100.0% (95% CI: 98.3-100.0%), respectively. Potential for false positives, preference for one blood draw over two, and shorter wait time for testing results were the highest ranked attributes by participants according to their willingness to test. The SD BIOLINE HIV/Syphilis Duo rapid test demonstrated very good performance in this field setting and participants preferred attributes that aligned well with this test.

Bior B, W. Dumo G, S. Katoro J, Mogga JJH, Lokore ML, G. Abias A, Y. Carter J, L. Deng L. Field evaluation of SD BIOLINE HIV/Syphilis Duo assay among pregnant women attending routine antenatal care in Juba, South Sudan

The SD BIOLINE HIV/Syphilis Duo assay is the first World Health Organization prequalified dual rapid diagnostic test for simultaneous detection of HIV and Treponema pallidum antibodies in human blood. Prior to introducing the test into antenatal clinics across South Sudan, a field evaluation of its clinical performance in diagnosing both HIV and syphilis in pregnant women was conducted. SD Bioline test performance on venous blood samples was compared with (i) Vironostika HIV1/2 Uniform II Ag/Ab reference standard and Alere Determine HIV 1/2 non-reference standard for HIV diagnosis, and (ii) Treponema pallidum hemagglutination reference standard and Rapid plasma reagin non-reference standard for syphilis. Sensitivity, specificity, positive predictive value (PPN), negative predictive value (NPV) and kappa (κ) value were calculated for each component against the reference standards within 95% confidence intervals (CIs); agreements between Determine HIV 1/2 and SD Bioline HIV tests were also calculated. Of 442 pregnant women recruited, eight (1.8%) were HIV positive, 22 (5.0%) had evidence of syphilis exposure; 14 (3.2%) had active infection. For HIV diagnosis, the sensitivity, specificity, PPV and NPV were 100% (95% CI: 63.1–100), 100% (95% CI: 99.2–100), 100% (95% CI: 63.1–100) and 100% (95% CI: 99.2–100) respectively with κ value of 1 (95% CI: 0.992–1.000). Overall agreement of the Duo HIV component and Determine test was 99.1% (95% CI: 0.977–0.998) with 66.7% (95% CI: 34.9–90.1) positive and 100% (95% CI: 0.992–1.000) negative percent agreements. For syphilis, the Duo assay sensitivity was 86.4% (95% CI: 65.1–97.1) and specificity 100% (95% CI: 99.1–100) with PPV 100% (95% CI: 82.4–100), NPV 99.2% (95% CI: 97.9–99.9) and κ value 0.92 (95% CI: 0.980–0.999). Our findings suggest the SD Bioline HIV/Syphilis Duo Assay could be suitable for HIV and syphilis testing in women attending antenatal services across South Sudan. Women with positive syphilis results should receive treatment immediately, whereas HIV positive women should undergo confirmatory testing following national HIV testing guidelines.

Clinic-based evaluation study of the diagnostic accuracy of a dual rapid test for the screening of HIV and syphilis in pregnant women in Nigeria

BACKGROUND

Screening pregnant women for HIV and syphilis is recommended by WHO in order to reduce mother-to-child transmission. We evaluated the field performance, feasibility, and acceptability of a dual rapid diagnostic test (RDT) for HIV and syphilis test in antenatal clinic settings in Nigeria.

METHODS AND FINDINGS

Participants were recruited at 12 antenatal clinic sites in three states of Nigeria. All consenting individuals were tested according to the national HIV testing algorithm, as well as a dual RDT, the SD BIOLINE HIV/Syphilis Duo Test (Alere, USA), in the clinic. To determine sensitivity, specificity and concordance, whole blood samples were obtained for repeat RDT performance in the laboratory, as well as reference tests for HIV and syphilis. Dual test acceptability and operational characteristics were assessed among participants and clinic staff. The prevalence of HIV among the 4,551 enrollees was 3.0% (138/4551) using the national clinic-based HIV testing algorithm. Positive and negative percent agreement of the HIV component of the dual RDT were 100.0% (95% CI 99.7-100.0) and 99.9% (95% CI 99.7-100.0) respectively, when compared with the national rapid testing algorithm. The prevalence of syphilis, using TPHA as the reference test, was low at 0.09% (4/4550). The sensitivity of the syphilis component of the dual RDT could not be calculated as no positive results were observed for patients that were positive for syphilis by TPHA. Each of the only four TPHA-positive specimens had RPR titers of 1:1 (neat), indicative of non-active syphilis. The specificity of the syphilis component of the dual RDT was 99.9% (95% CI 99.8-100.0). The dual RDT received favorable feasibility ratings among antenatal care clinic staff. Acceptability among study participants was high with most women reporting preference for rapid dual HIV/syphilis testing.

CONCLUSIONS

The SD BIOLINE HIV/Syphilis Duo Test showed a high overall diagnostic accuracy for HIV and a high specificity for syphilis diagnosis in antenatal clinic settings. This study adds to a growing body of evidence that supports the clinic-based use of dual tests for HIV and syphilis among pregnant women.

Distribution of reported syphilis cases in South China: spatiotemporal analysis

There was a varied spatial distribution of reported syphilis cases across cities in South China. This study aims to identify and describe spatiotemporal clusters of primary and secondary syphilis (P/S) cases in this region. Reported syphilis cases in Guangdong Province, China, from January 2014 to June 2015 were collected from the national centralized reporting system. Spatiotemporal clusters of P/S were identified and cross-validated by calculating local Moran's I, performing hotspot analysis (Getis-Ord Gi*), and constructing a discrete Poisson model in SaTScan. Reported cases within and outside the clusters were compared by bivariable and multivariable logistic regression. Out of 17,691 reported P/S cases, 11% were in the identified spatiotemporal clusters. The monthly P/S notification rate (per 100,000 persons) ranged between 0.6 and 1. The identified clusters were located in 14, out of 126, counties in eight, out of 21, cities. Cases of older age, living in rural area and taking self-initiated syphilis test were more likely to be in the clusters. Some areas bore a greater burden of P/S in Guangdong Province. Routine spatiotemporal analysis of P/S cases may be useful for enhancing syphilis control programs by strategic location-based service planning.

Expanding syphilis testing: a scoping review of syphilis testing interventions among key populations

INTRODUCTION

Syphilis is an important sexually transmitted infection (STI). Despite inexpensive and effective treatment, few key populations receive syphilis testing. Innovative strategies are needed to increase syphilis testing among key populations. Areas covered: This scoping review focused on strategies to increase syphilis testing in key populations (men who have sex with men (MSM), sex workers, people who use drugs, transgender people, and incarcerated individuals). Expert commentary: We identified many promising syphilis testing strategies, particularly among MSM. These innovations are separated into diagnostic, clinic-based, and non-clinic based strategies. In terms of diagnostics, self-testing, dried blood spots, and point-of-care testing can decentralize syphilis testing. Effective syphilis self-testing pilots suggest the need for further attention and research. In terms of clinic-based strategies, modifying default clinical procedures can nudge physicians to more frequently recommend syphilis testing. In terms of non-clinic based strategies, venue-based screening (e.g. in correctional facilities, drug rehabilitation centres) and mobile testing units have been successfully implemented in a variety of settings. Integration of syphilis with HIV testing may facilitate implementation in settings where individuals have increased sexual risk. There is a strong need for further syphilis testing research and programs.

Laboratory Evaluation of a Smartphone-Based Electronic Reader of Rapid Dual Point-of-Care Tests for Antibodies to Human Immunodeficiency Virus and Treponema pallidum Infections

BACKGROUND

Dual point-of-care tests for antibodies to human immunodeficiency virus (HIV) and Treponema pallidum allow for same-day testing and treatment and have been demonstrated to be cost-effective in preventing the adverse outcomes of HIV infection and syphilis. By recording and transmitting data as they are collected, electronic readers address challenges related to the decentralization of point-of-care testing.

METHODS

We evaluated a smartphone-based electronic reader using 201 sera tested with 2 dual rapid tests for detection of antibodies to HIV and T. pallidum in Los Angeles, USA, and Lima, Peru. Tests were read both visually and with the electronic reader. Enzyme immunoassay followed by Western blot and T. pallidum particle agglutination were the reference tests for HIV and T. pallidum, respectively.

RESULTS

The sensitivities of the 2 rapid tests for detection of HIV were 94.1% and 97.0% for electronic readings. Both tests had a specificity of 100% for detection of HIV by electronic reading. The sensitivities of the 2 rapid tests for detection of T. pallidum were 86.5% and 92.4% for electronic readings. The specificities for detection of T. pallidum were 99.1% and 99.0% by electronic reading. There were no significant differences between the accuracies of visual and electronic readings, and the performance did not differ between the 2 study sites.

CONCLUSIONS

Our results show the electronic reader to be a promising option for increasing the use of point-of-care testing programs.

A systematic review and meta-analysis of studies evaluating the performance and operational characteristics of dual point-of-care tests for HIV and syphilis

BACKGROUND

Mother-to-child transmission (MTCT) of syphilis and HIV continue to be important yet preventable causes of perinatal and infant morbidity and mortality.

OBJECTIVES

To systematically review, critically appraise and perform a meta-analysis to evaluate the operational characteristics of dual rapid diagnostic tests (RDTs) for HIV/syphilis and evaluate whether they are cost effective, acceptable and easy to use.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched seven electronic bibliographic databases from 2012 to December 2016 with no language restrictions. Search keywords included HIV, syphilis and diagnosis.

REVIEW METHODS

We included studies that evaluated the operational characteristics of dual HIV/syphilis RDTs. Outcomes included diagnostic test accuracy, cost effectiveness, ease of use and interpretation and acceptability. All studies were assessed against quality criteria and assessed for risk of bias.

RESULTS

Of 1914 identified papers, 18 were included for the meta-analysis of diagnostic accuracy for HIV and syphilis. All diagnostic accuracy evaluation studies showed a very high sensitivity and specificity for HIV and a lower, yet adequate, sensitivity and specificity for syphilis, with some variation among types of test. Dual screening for HIV and syphilis was more cost effective than single rapid tests for HIV and syphilis and prevented more adverse pregnancy outcomes. Qualitative data suggested dual RDTs were highly acceptable to clients, who cited time to result, cost and the requirement of a single finger prick as important characteristics of dual RDTs.

CONCLUSION

The results of this systematic review and meta-analysis can be used by policy-makers and national programme managers who are considering implementing dual RDTs for HIV and syphilis.

TRIAL REGISTRATION NUMBER

PROSPERO 2016:CRD42016049168.

Syphilis

Treponema pallidum subspecies pallidum (T. pallidum) causes syphilis via sexual exposure or via vertical transmission during pregnancy. T. pallidum is renowned for its invasiveness and immune-evasiveness; its clinical manifestations result from local inflammatory responses to replicating spirochaetes and often imitate those of other diseases. The spirochaete has a long latent period during which individuals have no signs or symptoms but can remain infectious. Despite the availability of simple diagnostic tests and the effectiveness of treatment with a single dose of long-acting penicillin, syphilis is re-emerging as a global public health problem, particularly among men who have sex with men (MSM) in high-income and middle-income countries. Syphilis also causes several hundred thousand stillbirths and neonatal deaths every year in developing nations. Although several low-income countries have achieved WHO targets for the elimination of congenital syphilis, an alarming increase in the prevalence of syphilis in HIV-infected MSM serves as a strong reminder of the tenacity of T. pallidum as a pathogen. Strong advocacy and community involvement are needed to ensure that syphilis is given a high priority on the global health agenda. More investment is needed in research on the interaction between HIV and syphilis in MSM as well as into improved diagnostics, a better test of cure, intensified public health measures and, ultimately, a vaccine.

Elimination of mother-to-child transmission of HIV and Syphilis (EMTCT): Process, progress, and program integration

Melanie Taylor and colleagues discuss progress towards eliminating vertical transmission of HIV and syphilis.