Seroepidemiology of Syphilis Infection among 2 Million Reproductive-age Women in Rural China: A Population-based, Cross-sectional Study

Social and individual vulnerability factors associated with syphilis among populations living on islands in the Brazilian Amazon

BACKGROUND

The repercussions of the syphilis epidemic differ according to populations. Identifying and acknowledging the differences and specificities of populations is fundamental in the design and implementation of policies aimed at assisting the groups most vulnerable to syphilis.

OBJECTIVE

To estimate the prevalence of antibodies against Treponema pallidum and associated vulnerability factors among riverside populations of a capital city in the Brazilian Amazon.

METHODS

Cross-sectional study was conducted among residents of the periurban islands in Belém, northern Brazil, from August 2020 to January 2021. The inclusion criterion was being a resident of the riverside communities of the Combú Environmental Protection Area, aged 18 years or over. The participants responded to questionnaire and were tested for syphilis using rapid test. Data were analyzed using multiple logistic regression by Minitab version 20® software.

RESULTS

Overall, a total of 325 riverine were included. Age varied from 18 to 91 years (average 40 years). Prevalence of markers for syphilis was 5.9% (95% CI: 3.3%-8.4%). The multiple regression showed that as age increases, the chances of having syphilis also increase (p = 0.001; aOR: 1.04) and riverside dwellers with more than one sexual partner in the last 6 months had more than four chances of having syphilis compared to people who had only one sexual partner (p = 0.007; aOR: 4.20).

CONCLUSION

Syphilis circulates among traditional populations in the Amazon and is associated with factors of social and individual vulnerability.

Resurgence of congenital syphilis: new strategies against an old foe

Congenital syphilis is a major global cause of fetal loss, stillbirth, neonatal death, and congenital infection. In 2020, the global rate of congenital syphilis was 425 cases per 100 000 livebirths-substantially higher than WHO's elimination target of 50 cases per 100 000 livebirths. Case rates are rising in many high-income countries, but remain low compared with those in low-income and middle-income settings. This Review aims to summarise the current epidemiology and knowledge on transmission and treatment of syphilis in pregnancy, and proposes measures to reduce the rising incidence seen worldwide. We also describe emerging diagnostic and treatment tools to prevent vertical transmission and improve management of congenital syphilis. Finally, we outline a programme of public health priorities, which include research, clinical, and preventive strategies.

Preconception syphilis seroprevalence and association with duration of marriage and age among married individuals in Guangdong Province, China: A population-based cross-sectional study

BACKGROUND

Duration of marriage (DoM) and age are important characteristics of married individuals, who are the critical population for eliminating mother-to-child transmission (MTCT) of syphilis. A deep understanding of the preconception syphilis seroprevalence (PSS) and its distribution among this population may be able to help to eliminate MTCT. However, few population-based epidemiological studies have been focused on this group, and the association of DoM and age with PSS remains unclear.

METHODOLOGY/PRINCIPAL FINDINGS

This study used data from 4,826,214 married individuals aged 21-49 years who participated in the National Free Preconception Health Examination Project in Guangdong Province, China, between 2014 and 2019. Syphilis was screened using the rapid plasma reagin (RPR) test. The seroprevalence time series, seroprevalence map, and hot spot analysis (HSA) were employed to visualize the spatiotemporal distribution. The restricted cubic spline (RCS) based on multivariate logistic regression was used to model the association of DoM and age with PSS. The interactions on the additive scale of DoM and age were also assessed. The PSS was 266.61 per 100,000 persons (95% CI: 262.03-271.24) and the burden was higher in economically underdeveloped area within the province. A strong J-shaped non-linearity association was observed between age and PSS. Specifically, the risk of seropositivity was relatively flat until 27 years of age among men and increased rapidly afterwards, with an adjusted odds ratio (aOR) of 1.13 (95% CI: 1.12-1.13) per unit. Among women, the risk of seropositivity was relatively flat until 25 years of age and increased rapidly afterwards with an aOR of 1.08 (95% CI: 1.08-1.09) per unit. DoM was negatively associated with PSS among married individuals. Moreover, the combined effects of age and DoM appeared to be synergistic.

CONCLUSIONS/SIGNIFICANCE

Our findings suggest that attention should be paid to preventing syphilis in underdeveloped areas and that syphilis screening in newly married individuals who are in their late 20s or older should be recommended. Additionally, early syphilis prevention strategies should be implemented among young people as early as possible.

Couple-level determinants of syphilis infection among heterosexual married couples of reproductive age in Guangdong Province, China: A population-based cross-sectional study

Background

Syphilis remains a major public health problem worldwide, and its prevention requires knowledge of factors that go beyond the individual-level. However, most syphilis-related studies have focused on individual-level and regional-level factors, neglecting couple-level factors. Thus, this study aimed to explore couple-level determinants of syphilis infection among heterosexual married couples.

Methods

This population-based cross-sectional study used data from heterosexual married couples who participated in the National Free Preconception Health Examination Project in Guangdong Province, China during 2014-2019. The syphilis infection was tested by the rapid plasma reagin test. Couple-level data were obtained by combining information provided by the man and woman living in the same household. Multivariate logistic models were employed to explore the couple-level determinants of syphilis infection by gender after adjusting for potential confounders.

Results

A total of 1,755,156 couples were recruited in this analysis. The seroprevalence was 0.25% (95%CI: 0.24-0.25%) and 0.26% (95%CI: 0.25-0.27%) among men and women, respectively. The median age was 28.0 (interquartile range, IQR: 25.0-31.0) years, and the median duration of marriage was 0.2 (IQR: 0.0-2.5) years. After adjusting for individual and regional-level variables, duration of marriage was a protective factor for syphilis infection in men (adjusted odds ratios, AOR: 0.97; 95% CI: 0.96-0.98) and women (AOR: 0.95, 95% CI: 0.94-0.96). The age gap and the difference in education level between the husband and wife were associated with syphilis infection, but these associations were somewhat different between men and women. Condom use was negatively associated with syphilis infection in men (AOR: 0.77; 95% CI: 0.70-0.84) and women (AOR: 0.77, 95% CI: 0.71-0.84). Our results also showed that couple mobility and the number of children were not statistically significant determinants of syphilis infection among heterosexual married couples.

Conclusion

This study contributes to a more comprehensive understanding of syphilis outcomes in individuals in the context of marriage in China. Several couple-level factors are indeed associated with syphilis infection, but these associations differ between men and women. Couple-based strategies that engage both women and men and efforts to promote condom use among heterosexual married couples need to be developed and further evaluated for syphilis prevention.

Prevalence of reproductive tract infections among women preparing to conceive in Chongqing, China: trends and risk factors

Background

Reproductive tract infection has become a major public health issue all over the world for its high and growing prevalence. It can cause adverse pregnancy outcomes in pregnant women and their foetuses. This study aimed to investigate the trends and risk factors of the prevalence of reproductive tract infections among women who prepared to conceive in the Chongqing Municipality (China) from 2012 to 2016.

Methods

A multi-center cross-sectional study was conducted between January 2012 and December 2016. Women aged 20–49 years who intended to get pregnant were recruited for this study. All participants underwent preconception examination, which included testing for Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, syphilis, bacterial vaginosis and candidiasis according to the national diagnostic standard. A total of 439,372 women with testing results for all six types of reproductive tract infections were included in our final analyses. Logistic regression and factor analysis were used to determine the possible sociodemographic factors associated with prevalence trends.

Results

In our study, the overall positive rate of RTIs among the 439,372 women of reproductive age was 5.03%. Candidiasis was the most common infection in our population (2.47%), followed by bacterial vaginosis (1.28%), syphilis (0.73%), T. vaginalis (0.49%), C. trachomatis (0.20%) and N. gonorrhoeae (0.06%). The prevalence of reproductive tract infections was highest among women aged 35 years and above, with a primary or lower education level, history of pregnancy, delivery, induced abortion, or spontaneous abortion. From 2012 to 2016, the trend of the overall prevalence of reproductive tract infections was V-shaped, decreasing steadily from 2012 to 2015, with a slight rise in 2016. Our results suggest that the distribution change of age, education level, gravidity, parity, and history of induced abortion influenced this trend.

Conclusion

Since the number of high-risk women who intend to become pregnant is growing in the Chongqing Municipality, pre-conception positive preventions including health education, regular screening, and timely treatment of reproductive tract infections are needed to prevent the impact of reproductive tract infections on maternal health and infant safety.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12978-022-01502-x.

Reproductive tract infections (RTIs) can cause serious health problems, such as spontaneous abortion and congenital diseases in pregnant women and their foetuses. However, there is a lack of studies focusing on the prevalence of RTIs and their trends among women who intend to conceive. This cross-sectional study examined data collected from 439,372 women during their preconception care to investigate the trend and related risk factors of the prevalence of RTIs, thereby providing essential data for their prevention. Participants were women from all 39 counties in the Chongqing Municipality of China, and data were collected between 2012 and 2016. We found that the overall prevalence of the six types of RTIs among these women was 5.03%, which was relatively lower than that in other populations in previous studies. Age, education level, history of pregnancy or delivery, and history of abortion were all associated with the prevalence of RTIs. The prevalence trend from 2012 to 2016 was V-shaped decreased steadily from 2012 until 2015 and rose slightly in 2016. Our data suggested that this trend might be influenced by changes in the proportion of ‘high-risk’ women, that is, women with higher age, lower education level, and a history of pregnancy or induced abortion. This study suggests that health education and regular screening are necessary to face new challenges experienced by older women or women with previous pregnancies who intended to get pregnant in recent years in China.

Associations of toluidine red unheated serum test response to the treatment of syphilis in pregnancy and congenital syphilis: a 10-year real-world study

BACKGROUND

So far, there is a paucity of real-world data on the syphilis serological responses to the first-line treatment during pregnancy, and there is no relevant study on the necessity of anti-syphilis treatment during pregnancy for those patients who have been treated for syphilis before pregnancy for the prevention of mother-to-child transmission, which might provide valuable insight into treatment effectiveness and optimal management of pregnant women with syphilis.

METHODS

A retrospective study on 10 years of real-world data was performed for accumulative 410 Chinese pregnant women with syphilis. The descriptive statistics were conducted in the study, and toluidine red unheated serum test (TRUST) titer responses to penicillin treatment in syphilis-infected pregnant women, and the associations with congenital syphilis were investigated. We divided the patients into two groups according to the history of anti-syphilis treatment before pregnancy (patients diagnosed with syphilis who had received anti-syphilis treatment before pregnancy, and patients screened and diagnosed with syphilis during pregnancy who had no previous history of anti-syphilis treatment).

RESULTS

The rate of congenital syphilis in this study was 6.2% (25/406). There was no significant difference in the rate of congenital syphilis between patients who received anti-syphilis treatment before pregnancy and those who did not. Secondary syphilis and high baseline serum TRUST titer (≥1:8) in pregnant women were independent risk factors for congenital syphilis.

CONCLUSIONS

For the prevention of congenital syphilis, anti-syphilis treatment during pregnancy for syphilis seropositive pregnant women is needed, regardless of whether the patient has received anti-syphilis treatment before pregnancy, especially for those patients with secondary syphilis or high baseline serum TRUST titer, thus, timely surveillance, early diagnosis to timely treatment, and close syphilis reexamination during posttreatment follow-up, may help to reduce the above-mentioned risk factors for congenital syphilis.

Preconception reproductive tract infections status and adverse pregnancy outcomes: a population-based retrospective cohort study

Background

Reproductive tract infections can cause serious adverse outcomes for pregnant women such as spontaneous abortion and preterm birth. However, it is unclear whether maternal reproductive tract infection before pregnancy would also be related to any adverse pregnancy outcomes. This study aims to investigate the association of maternal preconception reproductive tract infections with subsequent adverse pregnancy outcomes.

Methods

A retrospective cohort study was conducted in the Chongqing Municipality of China between April 2010 and December 2016. A total of 57,586 women (57,708 pregnancies) from all 39 counties of Chongqing who participated in the National Free Preconception Health Examination Project were included. They all took preconception examinations for gonorrhea, chlamydia, trichomoniasis, syphilis, bacterial vaginosis and candidiasis before pregnancy within one year. Primary outcomes included spontaneous abortion (< 28 weeks gestation), preterm birth (< 37 weeks gestation), macrosomia and low birthweight.

Results

Of the 57,708 pregnancies, 2438 (4.22%) had at least one type of reproductive tract infections. Compared with women who were not infected with any reproductive tract infection before pregnancy, women with reproductive tract infections had a higher rate of spontaneous abortion (7.88% vs. 5.62%, p < 0.001). After analyzing by each infection, there were few significant associations between pre-pregnancy infections and adverse outcomes. Preconception syphilis infection was significantly associated with increased odds of spontaneous abortion (aOR = 2.07, 95%CI 1.50–2.85), induced abortion/labour due to medical reasons (aOR = 1.60, 95%CI 1.01–2.54) and preterm birth (aOR = 1.60, 95%CI 1.12–2.30) after adjusting for potential confounders. Preconception trichomoniasis was intended to relate to a higher risk of spontaneous abortion (aOR = 1.65, 95%CI 1.01–2.71), but its impact seemed to be attributed to its co-infection with other RTIs. Women who were chlamydia or bacterial vaginosis positive before pregnancy showed higher odds of macrosomia (aOR = 2.00, 95% CI 1.07–3.74 for chlamydia; aOR = 1.58, 95% CI 1.06–2.34 for bacterial vaginosis). Preconception bacterial vaginosis might also be associated with higher risks of very preterm birth (aOR = 2.16, 95%CI 1.23–3.78) and large for gestational age (aOR = 1.36, 95%CI 1.02–1.81).

Conclusions

Women with infections of the genital tract before pregnancy might also have increased risks of subsequent adverse outcomes including spontaneous abortion, preterm birth and macrosomia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04836-3.

Syphilis in riverine communities: prevalence and associated factors

OBJECTIVE

To estimate the prevalence of syphilis and associated factors in riverine communities.

METHOD

This is a cross-sectional and analytical study carried out with 250 riverside dwellers living in five communities in the city of João Pessoa, state of Paraíba. Data were collected through interviews and rapid screening tests to investigate syphilis. Bivariate, logistic regression and weight of evidence analysis were performed to identify the association between risk factors and behavior variables and rapid test positivity.

RESULTS

he prevalence of syphilis was 11.6% (95%CI: 7.5-15.6). Riverside dwellers who have a previous history of Sexually Transmitted Infection (OR 8.00; 95%CI: 2.76-23.2), history of imprisonment (OR 7.39; 95%CI: 1.61-33.7) and who reported having more than two sexual partners in the last 12 months (OR 4.31; 95%CI: 1.55-11.9) were more likely to be positive for syphilis.

CONCLUSION

High prevalence of syphilis among riverside dwellers and the presence of behavioral factors that increase vulnerability to acquiring the infection. The need to invest in preventive and screening strategies for syphilis in populations considered vulnerable is highlighted.

Intra-couple discordance in preconception syphilis screening for both spouses: a national and population-based survey in China, 2013-2018

OBJECTIVE

The antenatal screening strategy remains inadequate for eliminating congenital syphilis. To further eliminate maternal fetal transmission, preconception syphilis screening is considered an option. In this study, we investigated syphilis seropositivity and intra-couple discordance among married couples planning a pregnancy in China to provide essential baseline evidence for preconception syphilis screening.

DESIGN

Population-based survey.

SETTING

National preconception registered data.

POPULATION

Married Chinese couples planning conception within 6 months between 2013 and 2018.

METHODS

Syphilis was screened using rapid plasma reagin (RPR); infection self-reporting and sociodemographic characteristics were collected through questionnaires and medical records, respectively. r 3.2.2 and arcgis 10.2 were used for statistical analyses and geographic mapping.

MAIN OUTCOME MEASURES

RPR seropositivity.

RESULTS

Among 31 955 041 couples, 29 737 172 (93.06%) had complete RPR results for both spouses; of those, 0.62% (186 100) were seropositive, with dramatic intra-couple discordance, with 0.33% positivity in wives, 0.24% positivity in husbands and 0.05% positivity in both spouses. Across time, both seropositivity and intra-couple discordance remained stable. Seropositivity in different regions varied significantly, with provincial rates ranging geographically from Tibet (0.8%) to Hebei (0.2%) (P < 0.05). Economic level was an independent factor for this regional variation, with seropositivity increasing as gross domestic product income decreased (P < 0.05).

CONCLUSIONS

Intra-couple discordance in seropositivity for syphilis is notable among couples, with a considerable rate of pre-existing syphilis before pregnancy. Thus, screening both spouses during integrated preconception health care is recommended for further eliminating maternal-fetal transmission.

TWEETABLE ABSTRACT

Intra-couple discordance in seropositivity for syphilis is notable among couples, with a considerable rate of pre-existing syphilis before pregnancy. Screening both spouses during integrated preconception health care is recommended to further eliminate maternal-fetal transmission.

Nomadic Tibetan women's reproductive health: findings from cross-sectional surveys with a hard-to-reach population

Background

Western China has undergone substantial sociodemographic change, yet little is known about the health status of ethnic minority populations living in these areas.

Methods

We report findings from two cross-sectional surveys conducted with female Tibetan nomads living in rural areas of Western China/Eastern Tibet. We present results of descriptive analyses of data collected from reproductive-aged females who attended community health fairs in 2014 (n = 193) and 2016 (n = 298).

Results

On average, sexual debut preceded marriage among study participants, with fertility near replacement levels (2.7 and 2.1 in 2014 and 2016, respectively). Contraceptive use was common, and dominated by use of IUDs and female sterilization. Although over three-quarters (76%) of 2016 survey participants reported ever having at least one sexually transmitted infection (STI) symptom, there was low awareness of STIs (59%) and action to prevent STIs (21%). Younger women (< 40) were more likely to report having had had an STI symptom, as compared to older women (84% versus 71%; p < 0.05).

Conclusions

We demonstrate feasibility of collecting data with this hard-to-reach population. Reporting of STI symptoms warrants further investigation to identify and address health conditions in this population of Tibetan nomadic women, especially amidst broader social and contextual changes that may affect the Tibetan population.

Western China has undergone substantial sociodemographic change, yet little is known about the health status of ethnic minority populations living in these areas. We report findings from two cross-sectional surveys conducted with female Tibetan nomads living in rural areas of Western China/Eastern Tibet. We present results of descriptive analyses of data collected from reproductive-aged females who attended community health fairs in 2014 (n = 193) and 2016 (n = 298). On average, sexual debut preceded marriage among study participants, with fertility near replacement levels (2.7 and 2.1 in 2014 and 2016, respectively). Contraceptive use was common, and dominated by use of IUDs and female sterilization. Although over three-quarters (76%) of 2016 survey participants reported ever having at least one sexually transmitted infection (STI) symptom, there was low awareness of STIs (59%) and action to prevent STIs (21%). Younger women (less than 40 years old) were more likely to report having had had an STI symptom, as compared to women over 40 years old (84% versus 71%; p < 0.05). We demonstrate feasibility of collecting data with this hard-to-reach population. Reporting of STI symptoms warrants further investigation to identify and address health conditions in this population of Tibetan nomadic women, especially amidst broader social and contextual changes that may affect the Tibetan population.

Differences in maternal characteristics and pregnancy outcomes between syphilitic women with and without partner coinfection

BACKGROUND

Partner infection is a significant factor in preventing mother-to-child syphilis transmission. We compared pregnancy outcomes between syphilis discordant and syphilis concordant couples.

METHODS

We conducted a retrospective study among 3076 syphilis-positive women who received syphilis screening together with their partners during pregnancy. Multivariate analysis was used to explore risks for abnormal outcomes in objects correcting for the major covariate factors. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated to compare pregnancy outcomes between syphilis concordant and syphilis discordant couples.

RESULTS

Overall, 657 of the 3076 women were diagnosed with gestational syphilis and had a syphilis-positive partner, giving a partner concordance prevalence of 21.36%. Women in concordant couples were more likely to have higher parity, more children, late antenatal care and syphilis screening, a lower proportion of latent syphilis, and elevated serologic titers than women in discordant couples (P < 0.01 for all). Totally, 10.08% of women had adverse pregnancy outcomes. Multivariate analysis showed partners' syphilis infection (OR_adj = 1.44, 95% CI: 1.10-1.89), untreated pregnancy syphilis (OR_adj = 1.67, 95% CI: 1.15-2.43), and higher maternal serum titers (> 1:8) (OR_adj = 1.53, 95% CI: 1.17-2.00) increased the risks of adverse pregnancy outcomes. Concordance was associated with increased risk for stillbirth (OR_adj = 2.86, 95%CI:1.36-6.00), preterm birth (PTB) (OR_adj = 1.38,95%CI:1.02-1.87) and low birth weight (LBW) (OR_adj = 1.55, 95%CI:1.13-2.11) compared with discordance. Even among treated women, concordance was associated with increased risk for stillbirth (OR_adj = 3.26, 95%CI:1.45-7.31) and LBW (OR_adj = 1.52, 95%CI:1.08-2.14). Among women with one treatment course, the risks for PTB(OR_adj = 1.81, 95%CI:1.14-2.88) and LBW(OR_adj = 2.08, 95%CI:1.28-3.38)were also higher among concordant couples than discordant couples. Nevertheless, there were no significant differences between concordant and discordant couples in risks of stillbirth (OR_adj = 2.64, 95% CI: 0.98-7.05),PTB (OR_adj = 1.15, 95% CI: 0.76-1.74), and LBW(OR_adj = 1.21, 95% CI: 0.78-2.02) among women with two treatment courses.

CONCLUSION

Male partner coinfection increased the risks for stillbirth, PTB and LBW, particularly when gestational syphilis treatment was suboptimal. However, this risk could be reduced by adequate treatment.

Trends in the Epidemiology of Sexually Transmitted Disease, Acquired Immune Deficiency Syndrome (AIDS), Gonorrhea, and Syphilis, in the 31 Provinces of Mainland China

BACKGROUND This study aimed to investigate trends in the epidemiology of the leading sexually transmitted diseases (STDs), acquired immune deficiency syndrome (AIDS), gonorrhea, and syphilis, in the 31 provinces of mainland China. MATERIAL AND METHODS This retrospective study analyzed the incidence data of STDs from official reports in China between 2004 and 2016. The grey model first order one variable, or GM (1,1), time series forecasting model for epidemiological studies predicted the incidence of STDs based on the annual incidence reports from 31 Chinese mainland provinces. Hierarchical cluster analysis was used to group the prevalence of STDs within each province. RESULTS The prediction accuracy of the GM (1,1) model was high, based on data during the 13 years between 2004 and 2016. The model predicted that the incidence rates of AIDS and syphilis would continue to increase over the next two years. Cluster analysis showed that 31 provinces could be classified into four clusters according to similarities in the incidence of STDs. Group A (Sinkiang Province) had the highest reported prevalence of syphilis. Group B included provinces with a higher incidence of gonorrhea, mainly in the southeast coast of China. Group C consisted of southwest provinces with a higher incidence of AIDS. CONCLUSIONS The GM (1,1) model was predictive for the incidence of STDs in 31 provinces in China. The predicted incidence rates of AIDS and syphilis showed an upward trend. Regional distribution of the major STDs highlights the need for targeted prevention and control programs.