Rising syphilis rates in Canada, 2011-2020

Syphilis vaccine development: Aligning vaccine design with manufacturing requirements

Syphilis, caused by Treponema pallidum subsp. pallidum, is a global health concern with increasing rates worldwide. Current prevention strategies, including screen-and-treat approaches, are not sufficient to resolve rising infection rates, emphasizing the need for a vaccine. Developing a syphilis vaccine necessitates a range of cross-disciplinary considerations, including essential disease-specific protection, technical requirements, economic feasibility, manufacturing constraints, public acceptance, equitable vaccine access, alignment with global public vaccination programs, and identification of essential populations to be vaccinated to achieve herd immunity. Central to syphilis vaccine development is prioritization of global vaccine availability, including access in low- to middle-income settings. Various vaccine platforms, including subunit, virus-like particle (VLP), mRNA, and outer membrane vesicle (OMV) vaccines, present both advantages and challenges. The proactive consideration of both manufacturing feasibility and efficacy throughout the pre-clinical research and development stages is essential for producing an efficacious, inexpensive, and scalable syphilis vaccine to address the growing global health burden caused by this disease.

Notification rates for syphilis in women of reproductive age and congenital syphilis in Australia, 2011-2021: a retrospective cohort analysis of national notifications data

OBJECTIVES

To estimate notification rates for infectious syphilis in women of reproductive age and congenital syphilis in Australia.

STUDY DESIGN

Retrospective cohort study; analysis of national infectious syphilis and enhanced congenital syphilis surveillance data.

SETTING, PARTICIPANTS

Women aged 15-44 years diagnosed with infectious syphilis, and babies with congenital syphilis, Australia, 2011-2021.

MAIN OUTCOME MEASURES

Numbers and rates of infectious syphilis notifications, by Indigenous status and age group; numbers and rates of congenital syphilis, by Indigenous status of the infant; antenatal care history for mothers of infants born with congenital syphilis.

RESULTS

During 2011-2021, 5011 cases of infectious syphilis in women aged 15-44 years were notified. The notification rate for Aboriginal and Torres Strait Islander women rose from 56 (95% confidence interval [CI], 45-65) cases per 100 000 in 2011 to 227 (95% CI, 206-248) cases per 100 000 population in 2021; for non-Indigenous women, it rose from 1.1 (95% CI, 0.8-1.4) to 9.2 (95% CI, 8.4-10.1) cases per 100 000 population. The notification rate was higher for Aboriginal and Torres Strait Islander women than for non-Indigenous women (incidence rate ratio [IRR], 23.1; 95% CI, 19.7-27.1), lower for 15-24- (IRR, 0.7; 95% CI, 0.6-0.9) and 35-44-year-old women (IRR, 0.6; 95% CI, 0.5-0.7) than for 25-34-year-old women, and higher in remote regions than in major cities (IRR, 2.7; 95% CI, 2.2-3.8). During 2011-2021, 74 cases of congenital syphilis were notified, the annual number increasing from six in 2011 to a peak of 17 in 2020; the rate was consistently higher among Aboriginal and Torres Strait Islander infants than among non-Indigenous infants (2021: 38.3 v 2.1 per 100 000 live births). The mothers of 32 infants with congenital syphilis (43%) had not received antenatal care.

CONCLUSIONS

The number of infectious syphilis notifications for women of reproductive age increased in Australia during 2011-2021, as did the number of cases of congenital syphilis. To avert congenital syphilis, antenatal screening of pregnant women, followed by prompt treatment for infectious syphilis when diagnosed, needs to be improved.

Higher rates of laboratory-confirmed cases of syphilis in Western Canadian blood donors compared with Eastern Canadian blood donors following a period of societal re-opening

BACKGROUND AND OBJECTIVES

There is a growing infectious syphilis outbreak in Western Canada. Although blood donors are screened for syphilis risks, some blood donors will still be confirmed test-positive for syphilis. This study compares the characteristics of confirmed test-positive syphilis donations in both Western Canada and Eastern Canada, November 2022-August 2023.

MATERIALS AND METHODS

Donors were defined as Western or Eastern Canadian. Blood donations were tested for syphilis using the PK-TP assay (Beckman Coulter PK7300 Automated Microplate System). Confirmatory Treponema pallidum particle agglutination (TPPA) and rapid plasma reagin (RPR) assays were performed by one of two reference laboratories. An RPR titre ≥1:8 was used as a proxy for possible infectious syphilis.

RESULTS

Rates of laboratory-confirmed syphilis were higher in Western (n = 43, 13.4/100,000 donations) versus Eastern donors (n = 19, 4.7/100,000 donations; Fisher's exact test, two-sided, p ≤ 0.0001). Most syphilis confirmations were in first-time donors (Western Canada n = 31/43, 72.1%, Eastern Canada 12/19, 63.2%).

CONCLUSION

Although rates of laboratory-confirmed syphilis were higher in Western versus Eastern donors, Western donors did not have higher rates of infectious syphilis. Further studies might assess whether donors with laboratory-confirmed syphilis understood pre-donation screening questions or were completely unaware of a past infection.

Approach to sexually transmitted infection testing for men who have sex with men

OBJECTIVE

To provide a guide on appropriate sexually transmitted infection (STI) testing for primary care providers to use with patients who identify as men who have sex with men (MSM).

SOURCES OF INFORMATION

Canadian guidelines for STI testing and enteric and protozoan infections; Ontario guidelines for HIV screening and mpox; and US guidelines for STI testing.

MAIN MESSAGE

Across Canada rates of sexually transmitted bacterial, enteric, protozoan, and systemic infections-including HIV and mpox-have been steadily increasing among cisgender and transgender MSM. Despite often having similar clinical presentations, these infections have different incubation periods and testing approaches and must be ruled out effectively to guide diagnosis and treatment for MSM-identifying patients who present with symptoms of various conditions. Clinical information and screening recommendations, however, are often found in multiple guidelines rather than in a single source, thus further complicating these clinical encounters. This document provides a consolidated set of evidence and recommendations for STI testing in MSM.

CONCLUSION

Testing approaches for STIs should be comprehensive and based on the patient's reported risk factors and clinical presentation. Where ongoing STI risk is identified and negative laboratory test results are received, MSM should also be counselled on recommendations for repeat screening and HIV prevention services, such as preexposure prophylaxis.

Summary of the National Advisory Committee on Sexually Transmitted and Blood-Borne Infections (NAC-STBBI) Statement: Recommendations on Screening for Syphilis in Non-Pregnant Adults and Adolescents

Background

Sustained and significant increases in Canadian rates of infectious syphilis prompted the National Advisory Committee on Sexually Transmitted and Blood-Borne Infections (NAC-STBBI) to update the existing screening recommendation for non-pregnant adults and adolescents.

Methods

These guidelines were developed following the 2014 World Health Organization Handbook. The research question was: "What is the clinical utility of syphilis screening using risk-based versus population-wide approaches for adolescents and adults?" The evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

Results

The environmental scan included 11 guidelines on syphilis screening published between 2014 and January 2023. Two systematic reviews were identified and included. In the updated literature search from November 6, 2019, to January 17, 2023, there were no published systematic reviews on the effectiveness of risk-based screening or the comparison of risk-based and interval screening; however, one recent randomized control trial in Canada was published. Evidence for outcomes, patient values and preferences, resources, acceptability, equity, cost and cost effectiveness and feasibility were reviewed.

Conclusion

This statement provides two screening recommendations for adults and adolescents. Recommendation 1: NAC-STBBI recommends syphilis screening in all sexually active persons with a new or multiple partners and/or upon request of the individual. They also recommend screening every three to six months in individuals with multiple partners. Recommendation 2: NAC-STBBI recommends that targeted "opt-out" screening programs should be considered as frequently as every three months when serving population groups and/or communities experiencing a high prevalence of syphilis (and other STBBI). Both are strong recommendations with moderate certainty of evidence.

Validity of dried blood spot testing for sexually transmitted and blood-borne infections: A narrative systematic review

Testing for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) using dried blood spot (DBS) specimens has been an integral part of bio-behavioural surveillance in Canada for almost two decades, though less is known regarding the use of DBS in surveillance of other sexually transmitted and blood-borne infections (STBBI). A systematic review was conducted using a peer-reviewed search strategy to assess the current evidence regarding the validity of STBBI testing using DBS specimens. Eligibility criteria included studies reporting use of DBS specimens for STBBI testing with either commercially available or "in-house" tests in populations 15 years of age or older. Studies reporting a measure of validity such as sensitivity, specificity, positive and negative predictive values were eligible for inclusion. Quality of studies and risk of bias were assessed using the QUADAS-2 tool. A total of 7,132 records were identified. Of these, 174 met the criteria for inclusion. Among the studies that reported validity measures, a substantial proportion demonstrated high sensitivity (≥90%) in 62.5% of cases (N = 334/534 sensitivity measurements), and high specificity (≥90%) was observed in 84.9% of instances (N = 383/451 specificity measurements). However, the quality of the studies varied greatly. Our findings support the validity of the use of DBS specimens in STBBI testing where sufficient evidence was available, but validity is highly dependent on thorough method development and validation.

Interventions in maternal syphilis care globally: A scoping review

Infectious and Congenital Syphilis rates continue to rise globally. Current recommendations for syphilis screening and treatment may be insufficient, and there is a pressing need for improved programs and services to address the increase in cases. A scoping review was conducted to examine approaches to maternal syphilis screening and treatment. Theoretical underpinnings and the key characteristics of these interventions were studied to identify gaps in the existing literature to guide future research. Developing a modified version of the socio-ecological model to guide data analysis, we included 33 academic studies spanning 31 years, covering a range of interventions, programs, and policies globally. We highlight key facets of interventions aligning with the five levels of the modified model that include: individual, interpersonal, institutional, community and policy. In this review, we provide valuable insights into the characteristics and principles of maternal syphilis screening and treatment interventions.

Addressing the ethical problem of underdiagnosis in the post-pandemic Canadian healthcare system

Proper diagnosis is essential for effective treatment, yet in Canada health conditions are commonly underdiagnosed at all levels of the health system, meaning that they go undiagnosed or are diagnosed only after a delay. Underdiagnosis leads to inadequate treatment and potentially insufficient recovery and rehabilitation, as well as costly inefficiencies, such as repeat medical visits. Moreover, disparities in underdiagnosis in which vulnerable groups, such as women and Indigenous persons, are properly diagnosed at lower rates worsen existing inequities, which threatens the overall health of the general population. As health leaders and policy-makers seek to strengthen Canada's strained healthcare system, it will be important to address underdiagnosis and its causes, including systematic bias. Providing timely and accurate diagnoses for all patients is an essential component of delivering high quality, efficient, ethical, and cost-effective healthcare. The Canadian College of Health Leaders' Code of Ethics offers a framework for addressing underdiagnosis equitably. Utilizing the framework, suggestions are made for actions that can be taken at all levels of the health system to reduce underdiagnosis.

Reducing perinatal infection risk in newborns of mothers who received inadequate prenatal care

Inadequate prenatal care increases risk for maternal infections going undetected and untreated, putting both the mother's health and that of her infant at risk. When pregnant women present late to care, routine testing that impacts infant management should include: hepatitis B surface antigen (HBsAg); serology for hepatitis C virus (HCV), human immunodeficiency virus (HIV), and syphilis; and testing for Chlamydia trachomatis and Neisseria gonorrhoeae. If the mother was not tested before or after delivery and is not available for testing, the infant should undergo testing for HIV, HBV, HCV, and syphilis. Testing for C. trachomatis and N. gonorrhoeae should be undertaken if the infant develops compatible clinical manifestations. Rapid turnaround of test results for HIV, HBV, and syphilis is optimal because preventive treatment decisions are time-sensitive. Early and effective preventive interventions are available for newborns at risk for HIV, HBV, syphilis, or gonorrhea. Close clinical follow-up and follow-up testing of infants born to mothers with inadequate prenatal care are warranted, as not all infections can be fully excluded perinatally.

La réduction du risque d'infection périnatale chez les nouveau-nés de mères dont les soins prénatals étaient inappropriés

Le risque que des infections maternelles ne soient ni décelées ni traitées augmente lorsque les soins prénatals sont inappropriés, ce qui met la santé de la mère et de son nouveau-né à risque. Lorsqu'une femme enceinte se présente tardivement pour recevoir des soins, les tests systématiques qui influent sur la prise en charge du nouveau-né devraient inclure l'antigène de surface de l'hépatite B (AgHBs), la sérologie du virus de l'hépatite C (VHC), du virus de l'immunodéficience humaine (VIH) et de la syphilis, de même que le dépistage de la Chlamydia trachomatis et de la Neisseria gonorrhoeae. Si la mère ne s'est pas soumise aux dépistages avant ou après l'accouchement et qu'elle n'est pas disponible pour s'y soumettre, il faudrait procéder au dépistage du VIH, du virus de l'hépatite B (VHB), du VHC et de la syphilis chez le nouveau-né. Le dépistage de la C. trachomatis et de la N. gonorrhoeae est toutefois réservé aux cas où le nouveau-né démontre des manifestations cliniques compatibles avec ces infections. Il est optimal d'obtenir rapidement les résultats du dépistage du VIH, du VHB et de la syphilis, car l'utilisation des traitements préventifs est circonscrite dans le temps. Il existe des interventions préventives précoces et efficaces pour les nouveau-nés à risque de VIH, de VHB, de syphilis ou de gonorrhée. Un suivi clinique étroit et des tests de suivi s'imposent auprès des nouveau-nés de mères dont les soins prénatals étaient inappropriés, car il est impossible d'exclure pleinement toutes les infections pendant la période périnatale.

Infectious syphilis in women and heterosexual men in major Australian cities: sentinel surveillance data, 2011-2019

OBJECTIVES

To examine changes in the positive infectious syphilis test rate among women and heterosexual men in major Australian cities, and rate differences by social, biomedical, and behavioural determinants of health.

DESIGN, SETTING

Analysis of data extracted from de-identified patient records from 34 sexual health clinics participating in the Australian Collaboration for Coordinated Enhanced Sentinel Surveillance of Sexually Transmissible Infections and Blood Borne Viruses (ACCESS).

PARTICIPANTS

First tests during calendar year for women and heterosexual men aged 15 years or more in major cities who attended ACCESS sexual health clinics during 2011-2019.

MAIN OUTCOME MEASURES

Positive infectious syphilis test rate; change in annual positive test rate.

RESULTS

180 of 52 221 tested women (0.34%) and 239 of 36 341 heterosexual men (0.66%) were diagnosed with infectious syphilis. The positive test rate for women was 1.8 (95% confidence interval [CI], 0.9-3.2) per 1000 tests in 2011, 3.0 (95% CI, 2.0-4.2) per 1000 tests in 2019 (change per year: rate ratio [RR], 1.12; 95% CI, 1.01-1.25); for heterosexual men it was 6.1 (95% CI, 3.8-9.2) per 1000 tests in 2011 and 7.6 (95% CI, 5.6-10) per 1000 tests in 2019 (RR, 1.10; 95% CI, 1.03-1.17). In multivariable analyses, the positive test rate was higher for women (adjusted RR [aRR], 1.85; 95% CI, 1.34-2.55) and heterosexual men (aRR, 2.39; 95% CI, 1.53-3.74) in areas of greatest socio-economic disadvantage than for those in areas of least socio-economic disadvantage. It was also higher for Indigenous women (aRR, 2.39; 95% CI, 1.22-4.70) and for women who reported recent injection drug use (aRR, 4.87; 95% CI, 2.18-10.9) than for other women; it was lower for bisexual than heterosexual women (aRR, 0.48; 95% CI, 0.29-0.81) and for women who reported recent sex work (aRR, 0.35; 95% CI, 0.29-0.44). The positive test rate was higher for heterosexual men aged 40-49 years (aRR, 2.11; 95% CI, 1.42-3.12) or more than 50 years (aRR, 2.36; 95% CI, 1.53-3.65) than for those aged 15-29 years.

CONCLUSION

The positive test rate among both urban women and heterosexual men tested was higher in 2019 than in 2011. People who attend reproductive health or alcohol and drug services should be routinely screened for syphilis.

The 11th Canadian Symposium on Hepatitis C Virus: 'Getting back on track towards hepatitis C elimination'

Hepatitis C virus (HCV) affects approximately 204,000 Canadians. Safe and effective direct-acting antiviral therapies have contributed to decreased rates of chronic HCV infection and increased treatment uptake in Canada, but major challenges for HCV elimination remain. The 11th Canadian Symposium on Hepatitis C Virus took place in Ottawa, Ontario on May 13, 2022 as a hybrid conference themed 'Getting back on track towards hepatitis C elimination.' It brought together research scientists, clinicians, community health workers, patient advocates, community members, and public health officials to discuss priorities for HCV elimination in the wake of the COVID-19 pandemic, which had devastating effects on HCV care in Canada, particularly on priority populations. Plenary sessions showcased topical research from prominent international and national researchers, complemented by select abstract presentations. This event was hosted by the Canadian Network on Hepatitis C (CanHepC), with support from the Public Health Agency of Canada and the Canadian Institutes of Health Research and in partnership with the Canadian Liver Meeting. CanHepC has an established record in HCV research and in advocacy activities to address improved diagnosis and treatment, and immediate and long-term needs of those affected by HCV infection. The Symposium addressed the remaining challenges and barriers to HCV elimination in priority populations and principles for meaningful engagement of Indigenous communities and individuals with living and lived experience in HCV research. It emphasized the need for disaggregated data and simplified pathways for creating and monitoring interventions for equitably achieving elimination targets.

Crystal methamphetamine use and bacterial sexually transmitted infections (STIs) among gay, bisexual and other sexual minority men in Canada

OBJECTIVE

While crystal methamphetamine use by gay, bisexual, and other men who have sex with men (GBM) is associated with increased risk for sexually transmitted infection (STI) transmission, less is understood about the causal pathways between crystal methamphetamine use and STIs. We examined whether the association between greater crystal methamphetamine risk and prevalent bacterial STI diagnosis among GBM was mediated by two types of attitudinal variables: attitudes toward condoms, and sexual escape motives, defined as the use of substances to escape self-awareness during sex, and by sexual behaviors.

METHODS

We used computer-assisted self-interview questionnaires from 2449 sexually active GBM (18% living with HIV; median age = 33, interquartile range, 27-45) recruited via respondent-driven sampling in Vancouver, Toronto, and Montreal, Canada. Using the baseline data from the Engage cohort study, we fit a series of structural mediation models of the associations between greater crystal methamphetamine risk and bacterial STI (syphilis, gonorrhea, and chlamydia) diagnosis. We estimated indirect paths from greater crystal methamphetamine risk, attitudes toward condoms, sexual escape motives, and sexual risk behaviors, adjusting for self-reported demographic variables.

RESULTS

In the mediated model, the direct association between greater crystal methamphetamine risk and bacterial STI diagnosis was non-significant; however, five indirect paths were significant. Greater crystal methamphetamine risk was associated with bacterial STIs via condom use attitudes and escape motives, which in turn were associated with number of male anal sex partners, condomless anal sex, and oral sex.

DISCUSSION

Public health and counselling interventions for GBM who use crystal methamphetamine and who are at higher risk for STIs should target evidence-based causal paths that consider sexual attitudes and sexual practices.

Characteristics of polymerase chain reaction-positive syphilis cases in Manitoba, Canada, 2017 to 2020: Demographic analysis, specimen types, and Treponema pallidum gene targets

BACKGROUND

A resurgence of syphilis infections has been described in a number of countries including Canada in the last decade.

METHODS

This study identified polymerase chain reaction (PCR) positive syphilis cases based on detection of Treponema pallidum genes (polA, tpp47, and bmp) in 3,350 clinical specimens obtained from patients in the province of Manitoba, Canada between 2017 and 2020. Patient demographics were obtained from specimen requisition forms.

RESULTS

PCR identified 740 syphilis cases: 718 were adolescents and adults, while 22 were congenital syphilis cases. For non-congenital syphilis investigation, the clinical specimens with the highest yield of positive PCR results were genital (632), oral (73), and anal (55), while for congenital syphilis, they were nasal or nasopharyngeal secretions (20), followed by blood (5) and umbilical cord (4). Female syphilis cases appeared younger (61.7% between 14 and 29 years), while male syphilis cases appeared older (58.4% between 30 and 65 years). Although, overall more syphilis cases (62.7%) occurred in the urban cities; the proportion of urban cases showed a significant decline from 87.0% in 2017 to 55.6% in 2020, while in rural regions it increased from 13.0% in 2017 to 44.4% in 2020. Most (98.8%) PCR- positive specimens were found to contain all three T. pallidum genes and 99.8% also displayed the macrolide resistance genotype.

CONCLUSIONS

This study identified the clinical specimen types and T. pallidum genes most suitable for PCR diagnosis of syphilis. Changing demographics of cases were noted over time.