Syphilis in heterosexual women: case characteristics and risk factors for recent syphilis infection in Tokyo, Japan, 2017-2018

Epidemiology of Syphilis in Tokyo from 2019 to 2022: a Descriptive Epidemiological Study

In recent years, the incidence of syphilis in Tokyo has increased. This descriptive epidemiological study aimed to elucidate the status of syphilis within the city. Data regarding age, sex, disease stage, and presumed sexual partners of patients with syphilis reported in Tokyo were compiled and analyzed. A total of 9,419 patients with syphilis were diagnosed between 2019 and 2022. A sharp rise was observed in the number of reported cases from 2021 to 2022. Between 2020 and 2022, the number of women in their 20s who developed syphilis rapidly increased by more than 3-fold. Furthermore, the number of pregnant women with syphilis increased the end of 2022. Despite a rapid increase in the number of young women with syphilis, the incidence of congenital syphilis has remained stable. This stability may be attributed to the early detection of syphilis during pregnancy, facilitated by the high rate of antenatal checkups in Tokyo. However, the growing incidence of syphilis among young women could potentially lead to a rise congenital syphilis cases in the future. Therefore, public health strategies should include educational initiatives targeting high-risk populations and adolescents, along with early and appropriate testing and treatment to prevent the progression of syphilis.

Trends in Syphilis in Pregnant Women in Japan in 2016 and 2022

Since 2012, the rate of syphilis infection has increased dramatically in high-income countries including Japan. In this study, we examined the rate of syphilis infection among pregnant women and perinatal outcomes in the syphilis-infected pregnancy in 2022 in Japan, and compared the results with those in 2016. We requested 2,005 obstetric institutes to provide information on syphilis infection in pregnant women who delivered in 2022. A total of 1,346 obstetrical facilities responded with valid information. We compared the results with those in our previous study. The prevalence of syphilis-infected pregnant women was 1/1,215. The incidence of preterm delivery, intrauterine fetal demise and congenital syphilis in surviving neonates in the syphilis-infected pregnancy were 9%, 2% and 7%, respectively. The prevalence of syphilis-infected pregnant women has increased significantly, while the incidence of congenital syphilis seems to have decreased clinically.

Social and structural determinants associated with the prevalence of sexually transmitted infections among female commercial sex workers in Dhaka City, Bangladesh

Female commercial sex workers (FCSWs) bear higher rates of sexually transmitted infections (STIs) among key populations. The association of structural determinants and STIs among FCSWs was not at the forefront of research earlier in Bangladesh. This study examined how structural factors correlate with the prevalence of STIs at physical/social/economic/policy levels among FCSWs in Dhaka city. 495 FCSWs were screened for HIV, hepatitis B, and syphilis. Structural variables (Individual risks, high-risk sexual behaviors, work environments) were extracted from the previous multi-level study on FCSWs and analyzed in 2020 to determine whether macro/micro-structural factors were associated with STIs. The prevalence of STIs was 43.6% (95% CI: 39.1%-48). Most (n = 207/495) FCSWs were infected with Syphilis or Hepatitis B, only 1.8% had co-infection, and none was positive for HIV. Multiple logistic regression revealed that 'Individual risk' factors like age (≤18 years, adjusted odds ratio = AOR = .28; 18.1-29.9 years, AOR = .57), years in the sex industry (<1 year AOR = .15; 1-5 years, AOR = .39), and condoms as contraceptives (AOR = 2.7) were significantly associated with STIs. Considering 'High-risk behaviors' like monthly coitus with regular clients (AOR = .33), performing no anal sex ever (AOR = .03), and consistent condom use (AOR = .13) were less likely to be associated with STIs (P<0.05), while the association of ever group sex with STIs reported to double (AOR = 2.1). 'Work environment' like sex on roads/parks/shrines/markets (AOR = 2.6) and ever HIV-testing (AOR = 2.5) were significantly linked with STIs. However, micro-level factors like experiencing forced sex in the past year (AOR = 1.79) and condoms collected from hotel boys (AOR = .34) were significantly associated with STIs in the 'Hierarchical- model' with increasing model-power. 'Micro-structural' determinants predominated over 'Macro/policy-level factors' and profoundly influenced STIs. FCSWs need comprehensive and integrated interventions to promote accurate condom use perception, eliminate risky sexual behaviors, and provide quality reproductive health care. Necessary steps at the policy level are urgently needed to decriminalize commercial sex work.

HIV and syphilis testing for women and heterosexual men aged above 25 years in the Netherlands: possibilities for targeted testing at sexual health centres

OBJECTIVES

Targeted testing policy for HIV/syphilis at Dutch sexual health centres (SHCs) was evaluated for its efficiency in younger heterosexuals but not for heterosexuals ≥25 years. Currently, all older heterosexuals are tested for HIV/syphilis at SHCs. To explore possibilities for increased efficiency of testing in heterosexuals aged >25 years, this study aimed to identify determinants of HIV and syphilis diagnoses that could be used in targeted testing strategies.

DESIGN

An observational study using surveillance data from all Dutch SHC.

PARTICIPANTS

Women and heterosexual men aged >25 years visiting SHC between 2015 and 2021.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was HIV/syphilis diagnosis, determinants of a diagnosis were analysed. Based on these determinants and their applicability in SHC practice, different targeted testing scenarios were evaluated. For each scenario, the percentage of consultations involving HIV and syphilis testing and the total amount of missed HIV and syphilis diagnoses were calculated.

RESULTS

109 122 consultations were included among 75 718 individuals. The strongest determinants of HIV/syphilis diagnosis were HIV/syphilis-specific symptoms (adjusted OR (aOR) 34.9 (24.1-50.2)) and receiving partner notification (aOR 18.3 (13.2-25.2)), followed by low/middle education level (aOR 2.8 (2.0-4.0)), male sex (aOR 2.2 (1.6-3.0)) and age ≥30 years (aOR 1.8 (1.3-2.5)). When applying feasible determinants to targeted testing scenarios, HIV/syphilis testing would have been conducted in 54.5% of all consultations, missing 2 HIV and 3 syphilis diagnoses annually (13.4% and 11.4% of all diagnoses, respectively). In the scenario with the lowest number of missed HIV/syphilis diagnoses (0.3 HIV and 2 syphilis diagnoses annually), HIV/syphilis testing would have been conducted in 74.2% of all consultations.

CONCLUSIONS

In any targeted testing scenario studied, HIV and/or syphilis diagnoses would have been missed. This raises the question whether it is acceptable to put any of these scenarios into practice. This study contributes to a discussion about the impact of targeted testing policy.

Impact of the COVID-19 pandemic on the epidemiology of other communicable diseases in Japan

OBJECTIVES

To elucidate the impact of the COVID-19 pandemic on the epidemiology of other infectious diseases.

DESIGN

We investigated the epidemiology of 36 communicable diseases during 2015-2021 in Japan and compared the number of cases in each disease between the prepandemic (2015-2019) and intrapandemic (2020-2021) periods. Relationships between the incidence of the infectious diseases and the COVID-19 pandemic were also investigated.

RESULTS

Of 36 communicable diseases, the number of cases in the 27 diseases (75%) mainly caused by pathogens transmitted by droplet or contact was lower intrapandemic than prepandemic, and the cases of 21 diseases (58%) continued to decrease intrapandemic. The number of cases of six diseases (17%) was higher intrapandemic than prepandemic, and the cases of two diseases (5.6%), Japanese spotted fever and syphilis, continued to increase intrapandemic. Time trend analyses revealed a positive correlation between case numbers of communicable diseases and the COVID-19 pandemic, whereas the case numbers of hand-foot-and-mouth disease and respiratory syncytial virus infection rebounded in 2021 after decreasing in 2020.

CONCLUSION

The COVID-19 pandemic has greatly impacted the epidemiology of communicable diseases, suggesting that countermeasures against COVID-19 and lifestyle changes might be involved in these epidemiological changes.

Increased cervical Chlamydia trachomatis and syphilis infections in Japanese females of reproductive age in the late 2010s: Possible cause

From 2000 to 2019, Japan's reproductive-age population gradually declined by 24%. In comparison, the Chlamydia trachomatis infection rate increased from 2016, with the syphilis infection rate increasing more sharply from 2014. Since 2013, the numbers of foreign tourists to Japan have also increased. From 2011 to 2018, the rate of increase in tourists was 5.02 times, while the rate of increase in syphilis patients was higher at 22.4 times. The lack of a one-to-one relationship between foreign tourists and syphilis cases suggests that cases of syphilis were transmitted to others. Although the prevalence of syphilis in the tourists' home countries (Korea in 2014 and China in 2013) was 20-30 times higher than that in Japan, the Japanese sex industry did not discriminate against foreign tourists, leading to increased STI infections in Japanese female sex workers. Indeed, from 2017 to 2018, a history of working in the sex industry for six months was identified as a risk factor for syphilis. The rise in Chlamydia trachomatis infections has lagged behind that of syphilis by two years, with the rate of increase lower. We suspect the difference in increasing rates of syphilis and chlamydial infections is due to the different methods of infection: syphilis can be transmitted by light physical contact, such as a kiss, whereas chlamydia requires close sexual contact, such as oral sex or sexual intercourse. Regardless, examinations and infection control are necessary to prevent the spread of STIs in Japan due to inbound tourists.