Syphilis

Re-emergence of Syphilis: Where are we now?

Presented by: Dr. Carmen Lisboa
Div. of Microbiology, Department of Pathology, University of Porto
Dept. of Dermatovenereology, Centro Hospitalar S. João, Porto, Portugal

EXPAND ALL DOWNLOAD SLIDES

Global Syphilis Epidemiology

The epidemiology of syphilis is different around the world. In 2012, WHO estimated an incidence of 5.6 million new cases.¹ Syphilis presents a considerable problem in low income countries and cases are steadily increasing in higher income countries.¹^,² Untreated pregnant women who acquired a syphilis infection in the previous 4 years, have an 80% higher chance of fetal infections which may result in stillbirths or infant death in 40% of cases.³ Patients with syphilis have an increased likelihood of acquiring/transmitting HIV and their syphilis may progress to neurosyphilis at any stage of the disease. Lastly ocular syphilis leads to poor vision outcomes in 7% to 25% of cases.⁴^,⁵

Syphilis Epidemiology in the European Union⁶

Data from nations in the European Union have all reported increasing trends of syphilis infections from 2007 to 2016, with higher rates of infections in males and the steepest increase in men who have sex with men (MSM). In the European Union, incidence rate for 2016 is 6.1 cases per 100,000 population. The male-to-female ratio of syphilis infections is 7.9:1 with some variations within countries ranging from >10:1 in Ireland to <2:1 in Romania. The highest age group by gender with confirmed syphilis is the 25-34 male age group with 66% of being MSM. A total of 27% of HIV-positive patients were also coinfected with syphilis infection, 41% of which were MSM. There has been a relative downward trend of congenital syphilis with 37 cases reported in 2016.

Syphilis Epidemiology in the United States³

The United States has also been experiencing increases in syphilis infections. There was a steady decline in syphilis infections from 1941 to 2000. However, that number has been steadily increasing with 2.1 cases per 100,000 in 2001 to 8.7 cases per 100,000 in 2016. In 52% of syphilis cases, they were of MSM, while 6% of cases were men who have sex with men and women (MSMW).³ MSM also had a higher percentage (47%) of coinfection with HIV compared to 10.7% of men who have sex with women (MSW).³ There has also been a steady increase of congenital syphilis reported with 8.4 per 100,000 cases reported in 2012 to 15.7 per 100,00 cases in 2016.

Drivers of Increased Syphilis Infections

There are many factors that are believed to play a role in the increased infections rates of syphilis

As HIV is no longer perceived to be a fatal disease, the rate of condom use has decreased
Use of illicit drugs leading to “chem-sex”
Easy transmission of syphilis through oral and anal sex
Growth of sexual internet sites/social media
Travel between countries.

Key messages

Syphilis has recently re-emerged in several developed countries.
The syphilis increase was largely attributable to an increase among men, and in particular among MSM.
Among high-income countries with syphilis epidemics among MSM, transmission to women through male bisexual activity is a factor needing further study.
In developed countries congenital syphilis is on the rise.
The effective control of syphilis remains a challenge and new strategies are urgently needed.