Prevalence and incidence estimates for syphilis, chlamydia, gonorrhea, and congenital syphilis in Colombia, 1995-2016

Treponema pallidum genetic diversity and its implications for targeted vaccine development: A cross-sectional study of early syphilis cases in Southwestern Colombia

BACKGROUND

Venereal syphilis, caused by the spirochete Treponema pallidum subsp. pallidum (TPA), is surging worldwide, underscoring the need for a vaccine with global efficacy. Vaccine development requires an understanding of syphilis epidemiology and clinical presentation as well as genomic characterization of TPA strains circulating within at-risk populations. The aim of this study was to describe the clinical, demographic, and molecular features of early syphilis cases in Cali, Colombia.

METHODS AND FINDINGS

We conducted a cross-sectional study to identify individuals with early syphilis (ES) in Cali, Colombia through a city-wide network of public health centers, private sector HIV clinics and laboratory databases from public health institutions. Whole blood (WB), skin biopsies (SB), and genital and oral lesion swabs were obtained for measurement of treponemal burdens by polA quantitative polymerase chain reaction (qPCR) and for whole-genome sequencing (WGS). Among 1,966 individuals screened, 128 participants met enrollment criteria: 112 (87%) with secondary (SS), 15 (12%) with primary (PS) and one with early latent syphilis; 66/128 (52%) self-reported as heterosexual, while 48 (38%) were men who have sex with men (MSM). Genital ulcer swabs had the highest polA copy numbers (67 copies/μl) by qPCR with a positivity rate (PR) of 73%, while SS lesions had 42 polA copies/μl with PR of 62%. WB polA positivity was more frequent in SS than PS (42% vs 7%, respectively; p = 0.009). Isolation of TPA from WB by rabbit infectivity testing (RIT) was achieved in 5 (56%) of 9 ES WB samples tested. WGS from 33 Cali patient samples, along with 10 other genomic sequences from South America (9 from Peru, 1 from Argentina) used as comparators, confirmed that SS14 was the predominant clade, and that half of all samples had mutations associated with macrolide (i.e., azithromycin) resistance. Variability in the outer membrane protein (OMP) and vaccine candidate BamA (TP0326) was mapped onto the protein's predicted structure from AlphaFold. Despite the presence of mutations in several extracellular loops (ECLs), ECL4, an immunodominant loop and proven opsonic target, was highly conserved in this group of Colombian and South American TPA isolates.

CONCLUSIONS

This study offers new insights into the sociodemographic and clinical features of venereal syphilis in a highly endemic area of Colombia and illustrates how genomic sequencing of regionally prevalent TPA strains can inform vaccine development.

Spatiotemporal Bayesian modeling of the risk of congenital syphilis in São Paulo, SP, Brazil

The aim of this study is to analyze the spatiotemporal risk of congenital syphilis (CS) in high-prevalence areas in the city of São Paulo, SP, Brazil, and to evaluate its relationship with socioeconomic, demographic, and environmental variables. An ecological study was conducted based on secondary CS data with spatiotemporal components collected from 310 areas between 2010 and 2016. The data were modeled in a Bayesian context using the integrated nested Laplace approximation (INLA) method. Risk maps showed an increasing CS trend over time and highlighted the areas that presented the highest and lowest risk in each year. The model showed that the factors positively associated with a higher risk of CS were the Gini index and the proportion of women aged 18-24 years without education or with incomplete primary education, while the factors negatively associated were the proportion of women of childbearing age and the mean per capita income.

Syphilis prevalence and correlates of infection among Venezuelan refugees and migrants in Colombia: findings of a cross-sectional biobehavioral survey

Background

Population-based estimates of syphilis prevalence are critical to informing public health response. We aimed to measure syphilis prevalence among Venezuelan refugees and migrants in Colombia to inform public health programming.

Methods

Between July 2021 and February 2022, we surveyed 6221 adult Venezuelan refugees and migrants in four cities in Colombia using respondent-driven sampling (RDS). Participants completed a survey and dual-rapid HIV/treponemal syphilis screening. Confirmatory laboratory-based rapid plasma reagin testing was conducted on whole blood samples. Active syphilis infection was defined as RPR titer ≥ 1:8 and no self-reported syphilis treatment. We used multivariable regression models to identify associations with active syphilis infection among subgroups by gender and history of pregnancy (cisgender men n = 2123, cisgender women n = 4044, transgender/nonbinary people n = 47, pregnant women n = 150).

Findings

Population (RDS-weighted) prevalence of laboratory-confirmed syphilis was 5.1% (95% CI: 4.6-5.6). Syphilis prevalence was 5.8% (weighted) among men; lifetime sexually transmitted infections (STI) diagnosis, same-sex relationships, HIV infection, and partner number were independently associated with syphilis infection. Syphilis prevalence was 4.6% (weighted) in women; correlates of infection included: lifetime STI diagnosis, food insecurity, current engagement in sex work, current pregnancy, any unsafe night in Colombia, irregular migration status, and no healthcare utilization in Colombia. 14.9% (unweighted) of transgender participants had syphilis infection; correlates of infection included partner number and HIV infection. The prevalence of syphilis was 9.0% (weighted) among pregnant women, which was associated with lifetime STI diagnosis.

Interpretation

Syphilis among Venezuelans in Colombia is high. Correlates of infection are distinct among demographic groups, spanning sexual and social vulnerabilities, suggesting tailored public health strategies.

Funding

US President's Emergency Plan for AIDS Relief through the U.S. Centers for Disease Control and Prevention.

Gonorrhea prevalence in adults in Brazil: Spectrum-STI trend estimation, 2000-2020

BACKGROUND

Gonorrhea is not a notifiable disease in Brazil, and the national health information system does not collect data on reported cases or infection prevalence.

METHODS

We compiled published data on gonorrhea prevalence in Brazil from cross-sectional surveys and clinical trials between 2000 and 2020. The study entry criteria included a sample size of 50 or more, and Neisseria gonorrhoeae infection detected in urine, urethral, anal, or cervicovaginal specimens using either Nucleic Acid Amplification Test or culture. Gonorrhea prevalence trends between 2000 and 2020 were generated using Spectrum-STI, a statistical trend-fitting model.

RESULTS

Forty-five studies with 59 gonorrhea prevalence data points were identified. Fifty data points were for women and represented 21,815 individuals, eight for men encompassing a total of 4,587 individuals, and one for transgender people comprising 345 individuals. The Spectrum-STI estimate for the prevalence of urogenital infection with gonorrhea in women 15-49 in 2020 was 0.63% (95% confidence interval (CI): 0.13-2.23) and was lower than the 1.05% estimated value for 2000 (95% CI: 0.36-2.79). The corresponding figures for men were 0.70% (95% CI: 0.16-2.44) and 1.14% (95% CI: 0.34-3.15). Anal prevalence estimates could not be generated because of insufficient data (three data points).

CONCLUSIONS

These results suggest that the overall prevalence of genitourinary gonococcal infections in Brazil is less than 1%. Data on gonorrhea prevalence in men and in populations at increased STI vulnerability are limited.

Diagnostic performance of two rapid tests for syphilis screening in people living with HIV in Cali, Colombia

INTRODUCTION

There is insufficient evidence supporting the use of rapid diagnostic tests (RDTs) for syphilis in people living with HIV (PLWH). We evaluated the diagnostic performance of two commercially available RDTs (Bioline and Determine) in PLWH in Cali, Colombia.

METHODS

A cross-sectional field validation study on consecutive adults with confirmed HIV diagnosis attending three outpatient clinics. Both RDTs were performed on capillary blood (CB), obtained by finger prick, and sera, by venipuncture. A combination of treponemal enzyme linked immunosorbent assay (ELISA) and Treponema pallidum haemagglutination assay (TPHA) on serum samples was the reference standard. Rapid plasma reagin (RPR) and clinical criteria were added to define active syphilis. Sensitivity and specificity, predictive values and likelihood ratios (LR) of RDTs were estimated with their corresponding 95% confidence interval (95% CI). Stratified analyses by sample type, patient characteristics, non-treponemal titers, operator and re-training were performed.

RESULTS

244 PLWH were enrolled, of whom 112 (46%) had positive treponemal reference tests and 26/234 (11.1%) had active syphilis. The sensitivities of Bioline on CB and sera were similar (96.4% vs 94.6%, p = 0.6). In contrast, Determine had a lower sensitivity on CB than sera (87.5% vs 99.1%, p<0.001). Sensitivities were lower in PLWH not receiving ART (Bioline 87.1% and Determine 64.5%, p<0.001) and for one of the operators (Bioline 85% and Determine 60%, p<0.001). Specificities of the RDTs were > 95% in most analyses. Predictive values were 90% or higher. For active syphilis, the RDTs showed a similar performance pattern but with decreased specificities.

CONCLUSION

The studied RDTs have an excellent performance in PLWH to screen for syphilis and potentially for active syphilis, yet Determine performs better on sera than CB. Patient characteristics and potential difficulties operators may face in acquiring enough blood volume from finger pricks should be considered for the implementation and the interpretation of RDTs.

A systematic review of the prevalence of selected sexually transmitted infections in young people in Latin America

Objective

To estimate the burden of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Treponema pallidum (TP), and human papillomavirus (HPV) infections among people aged 10 to 25 in Latin America and the Caribbean.

Methods

The MEDLINE, EMBASE, and LILACS databases were searched, as well as documents from regional organizations or national health Institutions. Population-based studies that reported prevalence or incidence of CT, NG, TP, and HPV detected through confirmatory tests in adolescents and young people were included. Two reviewers independently selected studies and extracted data. The quality of studies was assessed using the Newcastle-Ottawa Scale. Pooled estimators were calculated in cases where heterogeneity was <70%; when not feasible, prevalence ranges were reported.

Results

Out of a total of 3 583 references, 15 prevalence studies complied with the inclusion criteria. Due to substantial heterogeneity (>70%), it was not possible to pool frequency estimators. Among the general population, the prevalence of CT infection ranged between 2.1% and 30.1% (9 studies, 5 670 participants); for NG, prevalence ranged between 0% and 2.9% (8 studies, 5 855 participants); for TP, prevalence varied between 0% and 0.7% (3 studies, 11 208 participants), and for HPV infection, prevalence ranged between 25.1% and 55.6% (8 studies, 3 831 participants).

Conclusions

Reliable, population-based data on sexually transmitted infections (STIs) in adolescents and youth in Latin America and the Caribbean are limited. Additional studies are needed to better understand the burden of STIs in this population. However, given the substantial prevalence of STIs detected, countries need public health policies for prevention, early diagnosis, and treatment of STIs in young people.

Incidence Trends of Five Common Sexually Transmitted Infections Excluding HIV From 1990 to 2019 at the Global, Regional, and National Levels: Results From the Global Burden of Disease Study 2019

Objective

Sexually transmitted infections (STIs) are common worldwide and pose a challenge to public health. We conducted this study to assess the annual incidence of five common STIs, including syphilis, chlamydia, gonorrhea, trichomoniasis, and genital herpes at the global, regional, and national levels.

Materials and Methods

We obtained detailed data on STIs excluding HIV from 1990 to 2019 from the Global Burden of Disease (GBD) 2019 database. Estimated annual percentage change (EAPC) was calculated to quantify trends in age-standardized incidence rates (ASR) of STIs, stratified by gender, sociodemographic index (SDI) region, and pathogenic microorganism.

Results

Globally, incident cases of STIs increased by 58.15% from 486.77 million in 1990 to 769.85 million in 2019, but the annual change in ASR was only -0.04% (95% CI -0.09 to 0.01) per year. EAPC was 0.16 (0.06 to 0.26) for syphilis, 0.09 (0.05 to 0.13) for genital herpes, 0.06 (0.03 to 0.09) for trichomoniasis, -0.21 (-0.36 to -0.06) for chlamydia, and -0.14 (-0.19 to -0.08) for gonorrhea. High SDI regions reported significant increases in ASR of syphilis and chlamydia.

Conclusions

The burden of disease from STIs remains large, though control of STIs has contributed to the decreasing incidence in most regions, especially in the low-SDI regions. Globally, over the past 20 years, the ASR has remained stable for trichomoniasis and genital herpes decreased for chlamydia and gonorrhea, and increased for syphilis.

Characterization of sexually transmitted infections, their pharmacological treatment, and recurrence in a Colombian population

Introduction:

Sexually transmitted infections are a public health problem worldwide. Their inadequate antimicrobial management has been associated with a higher risk of recurrence.

Objective:

To characterize the main sexually transmitted infections, the adherence to clinical practice guidelines, and the factors associated with recurrence in Colombia.

Materials and methods:

We conducted an observational study to identify the main sexually transmitted infections, the sociodemographic variables, and the pharmacological management in a patient cohort from a population database of 6.5 million people affiliated with the Colombian health system. We made a multivariate analysis to identify the variables associated with recurrence.

Results:

We detected 3,158 patients with a mean age of 41.8 ± 14.5 years, of whom 63.1% were men. We found 4.030 episodes of sexually transmitted infections, predominantly urethral syndrome (27.5%). Only 13.6% of patients with urethral syndrome, ulcerative syndrome, or genital warts were managed in compliance with clinical practice guidelines and 20.6% were dispensed condoms; 16.7% of patients had recurrences and being male (OR=1.32; 95%CI 1.08-1.63), <30 years old (OR=1.72; 95%CI 1.40-2.13), being treated in municipalities other than capital cities (OR=1.43; 95%CI 1.06-1.94), and having received inadequate treatment for the first episode (OR=1.93; 95%CI 1.52-2.39) were associated with recurrence.

Conclusions:

The majority of patients with sexually transmitted infections were not treated in compliance with clinical practice guidelines and those who did not have adequate management had a higher risk of recurrence.

Chlamydia trachomatis, virus herpes simple-2 y Neisseria gonohrroeae: prevalencia y factores de riesgo en estudiantes

Objetivo Determinar la prevalencia de Chlamydia trachomatis (CT), virus herpes simple-2 (VHS-2) y N. gonorrhoeae (NG) y los factores de riesgo relacionados con la infección, en un grupo de estudiantes universitarios de la ciudad de Medellín. Metodología Se realizó un estudio descriptivo en un grupo de 323 estudiantes universitarios. A través de un formulario en línea, se realizó el reporte de los factores de riesgo y síntomas relacionados con infecciones de transmisión sexual (ITS) y luego se determinó la presencia de anticuerpos IgG y IgM para CT y VHS-2 y se realizó una prueba de PCR-RT para detectar NG y CT. Resultados La frecuencia de IgG para CT fue del 13% y la positividad para IgM fue del 11,9%. La frecuencia de IgG para VHS-2 fue del 11,8% y la frecuencia de CT y NG por la prueba PCR-RT fue del 1,5% y del 0%, respectivamente. Los factores de riesgo más frecuentes fueron: vida sexual activa en el 96,9%, uso algunas veces o nunca del condón en un 75,2%. Reportaron que tenían secreción genital el 13,6% de los estudiantes; úlceras, el 2,8%; verrugas, el 5,3%; ardor al orinar, el 15,5%; ampollas, el 4,6%, y diagnóstico previo de una ITS, el 18,9% de los estudiantes. Conclusión Se encontró CT y VHS-2 entre los jóvenes estudiados y además una alta frecuencia de factores de riesgo para la adquisición de ITS. Se recomienda mejorar las campañas de prevención y diagnóstico de las ITS en los jóvenes universitarios.

Prevalence of syphilis, gonorrhoea and chlamydia in women in Fiji, the Federated States of Micronesia, Papua New Guinea and Samoa, 1995-2017: Spectrum-STI model estimates

Objective

To estimate prevalence levels of and time trends for active syphilis, gonorrhoea and chlamydia in women aged 15-49 years in four countries in the Pacific (Fiji, the Federated States of Micronesia [FSM], Papua New Guinea [PNG] and Samoa) to inform surveillance and control strategies for sexually transmitted infections (STIs).

Methods

The Spectrum-STI model was fitted to data from prevalence surveys and screenings of adult female populations collected during 1995-2017 and adjusted for diagnostic test performance and to account for undersampled high-risk populations. For chlamydia and gonorrhoea, data were further adjusted for age and differences between urban and rural areas.

Results

Prevalence levels were estimated as a percentage (95% confidence interval). In 2017, active syphilis prevalence was estimated in Fiji at 3.89% (2.82 to 5.06), in FSM at 1.48% (0.93 to 2.16), in PNG at 3.91% (1.67 to 7.24) and in Samoa at 0.16% (0.07 to 0.37). For gonorrhoea, the prevalence in Fiji was 1.63% (0.50 to 3.87); in FSM it was 1.59% (0.49 to 3.58); in PNG it was 11.0% (7.25 to 16.1); and in Samoa it was 1.61% (1.17 to 2.19). The prevalence of chlamydia in Fiji was 24.1% (16.5 to 32.7); in FSM it was 23.9% (18.5 to 30.6); in PNG it was 14.8% (7.39 to 24.7); and in Samoa it was 30.6% (26.8 to 35.0). For each specific disease within each country, the 95% confidence intervals overlapped for 2000 and 2017, although in PNG the 2017 estimates for all three STIs were below the 2000 estimates. These patterns were robust in the sensitivity analyses.

Discussion

This study demonstrated a persistently high prevalence of three major bacterial STIs across four countries in WHO's Western Pacific Region during nearly two decades. Further strengthening of strategies to control and prevent STIs is warranted.

The Spectrum-STI Groups model: syphilis prevalence trends across high-risk and lower-risk populations in Yunnan, China

The Spectrum-STI model, structured by sub-groups within a population, was used in a workshop in Yunnan, China, to estimate provincial trends in active syphilis in 15 to 49-year-old adults. Syphilis prevalence data from female sex workers (FSW), men who have sex with men (MSM), and lower-risk women and men in Yunnan were identified through literature searches and local experts. Sources included antenatal care clinic screening, blood donor screening, HIV/STI bio-behavioural surveys, sentinel surveillance, and epidemiology studies. The 2017 provincial syphilis prevalence estimates were 0.26% (95% confidence interval 0.17-0.34%) in women and 0.28% (0.20-0.36%) in men. Estimated prevalence was 6.8-fold higher in FSW (1.69% (0.68-3.97%) than in lower-risk women (0.25% (0.18-0.35%)), and 22.7-fold higher in MSM (5.35% (2.74-12.47%) than in lower-risk men (0.24% (0.17-0.31%). For all populations, the 2017 estimates were below the 2005 estimates, but differences were not significant. In 2017 FSW and MSM together accounted for 9.3% of prevalent cases. These estimates suggest Yunnan's STI programs have kept the overall prevalence of syphilis low, but prevalence remains high in FSW and MSM. Strengthening efforts targeting FSW and MSM, and identification of other risk populations e.g. among heterosexual men, are critical to reduce syphilis.

[Inequalities in congenital syphilis trends in the city of Niterói, Brazil, 2007-2016Desigualdades en la tendencia de sífilis congénita en la ciudad de Niterói, Brasil, 2007-2016]

Objetivo.

Descrever a distribuição temporal e as características epidemiológicas da sífilis congênita (SC) em Niterói, Sudeste do Brasil, de 2007 a 2016.

Métodos.

Este estudo descritivo de série temporal da incidência de SC utilizou os dados do Sistema de Informação de Agravos de Notificação (SINAN) e do Sistema de Informações sobre Nascidos Vivos (SINASC). A amostra incluiu todos os casos notificados. Além disso, foi realizado um relacionamento probabilístico entre SINAN e SINASC para recuperar informações ignoradas. A série temporal foi estimada por regressão logarítmica, de acordo com variáveis sociodemográficas e de pré-natal.

Resultados.

Identificaram-se 754 casos de SC no período estudado (incidência média de 11,9 casos/1 000 nascidos vivos). A incidência foi mais elevada em jovens (10 a 19 anos; 20 a 24 anos), participantes de cor preta e naquelas com baixa escolaridade e sem pré-natal. Do total de mulheres, apenas 57,6% obtiveram o diagnóstico de sífilis durante o pré-natal. O tratamento foi inadequado em 87,7% das mulheres. Apenas 12,2% dos parceiros foram tratados. Houve tendência crescente do agravo (16%/ano), que atingiu 23,2 casos/1 000 nascidos vivos em 2016. O crescimento foi mais acentuado em adolescentes do sexo feminino (25,2%/ano), raça/cor parda (16,8%/ano), indivíduos com baixa escolaridade (57,1%/ano) e mulheres que realizaram pré-natal (17,3%/ano); e, no período de 2012 a 2016, em mulheres com informação ignorada para a cor da pele.

Conclusões.

As iniquidades sociais se destacaram na ocorrência de SC, com incidência crescente em jovens. É necessária a capacitação dos profissionais de saúde para o manejo da sífilis gestacional e uma atuação efetiva das políticas públicas sobre os determinantes sociais da sífilis.

Global burden of maternal and congenital syphilis and associated adverse birth outcomes-Estimates for 2016 and progress since 2012

BACKGROUND

In 2007 the World Health Organization (WHO) launched the global initiative to eliminate mother-to-child transmission of syphilis (congenital syphilis, or CS). To assess progress towards the goal of <50 CS cases per 100,000 live births, we generated regional and global estimates of maternal and congenital syphilis for 2016 and updated the 2012 estimates.

METHODS

Maternal syphilis estimates were generated using the Spectrum-STI model, fitted to sentinel surveys and routine testing of pregnant women during antenatal care (ANC) and other representative population data. Global and regional estimates of CS used the same approach as previous WHO estimates.

RESULTS

The estimated global maternal syphilis prevalence in 2016 was 0.69% (95% confidence interval: 0.57-0.81%) resulting in a global CS rate of 473 (385-561) per 100,000 live births and 661,000 (538,000-784,000) total CS cases, including 355,000 (290,000-419,000) adverse birth outcomes (ABO) and 306,000 (249,000-363,000) non-clinical CS cases (infants without clinical signs born to un-treated mothers). The ABOs included 143,000 early fetal deaths and stillbirths, 61,000 neonatal deaths, 41,000 preterm or low-birth weight births, and 109,000 infants with clinical CS. Of these ABOs- 203,000 (57%) occurred in pregnant women attending ANC but not screened for syphilis; 74,000 (21%) in mothers not enrolled in ANC, 55,000 (16%) in mothers screened but not treated, and 23,000 (6%) in mothers enrolled, screened and treated. The revised 2012 estimates were 0.70% (95% CI: 0.63-0.77%) maternal prevalence, and 748,000 CS cases (539 per 100,000 live births) including 397,000 (361,000-432,000) ABOs. The estimated decrease in CS case rates between 2012 and 2016 reflected increased access to ANC and to syphilis screening and treatment.

CONCLUSIONS

Congenital syphilis decreased worldwide between 2012 and 2016, although maternal prevalence was stable. Achieving global CS elimination, however, will require improving access to early syphilis screening and treatment in ANC, clinically monitoring all women diagnosed with syphilis and their infants, improving partner management, and reducing syphilis prevalence in the general population by expanding testing, treatment and partner referral beyond ANC.