The number of syphilis cases has been consistently going up across Europe since 2010, mostly affecting men who have sex with men living in urban areas. In 2017, notification rates reached an all-time high in the EU/EEA countries with more than 33,000 reported cases. An in-depth ECDC study describes the factors behind this increase and outlines the evidence-based options for public health control of syphilis, including case finding and management as well as educational activities.
Overall, more than 260,000 confirmed syphilis cases were reported from 30 EU/EEA countries between 2007 and 2017. While annual notifications decreased slightly between 2007 and 2010 (from almost 20,000 to a low of some 19,000 cases), they continuously rose to more than 33,000 cases in 2017. An all-time high since the start of ECDC surveillance recording.
This trend results from notification data of the 23 countries with comprehensive surveillance systems reporting consistently between 2007 and 2017. The rate dropped to a low of 4.2 per 100 000 persons in 2010, before reaching an EU/EEA peak of 7.1 per 100,000 population in 2017 -- an increase of 70% compared with the notification rate in 2010. This means that for the first time since the early 2000s, the EU/EEA countries report more syphilis than HIV cases.
Between 2010 and 2017, 15 countries reported an increase in the notification rate of more than 15%. However, this varied greatly among countries with rates more than doubling in five countries: Iceland (876%), Ireland (224%), the United Kingdom (153%), Germany (144%) and Malta (123%). On the other hand, Estonia and Romania reported a drop of 50% or more over the same period.
During this period, syphilis diagnoses were consistently higher among men, with rates doubling from 6.1 per 100,000 in 2010 to 12.1 in 2017. Between 2007 and 2017, close to two-thirds (62%, 94,015 of the 152,233 cases where sexual orientation was known) were reported among men who have sex with men. Heterosexual men contributed 23% of cases and women 15%. The proportion of cases diagnosed among men who have sex with men ranged from below 20% in Latvia, Lithuania and Romania to more than 80% in France, Germany, Ireland, the Netherlands, Sweden and the United Kingdom.
The ECDC study looked at more than 60 studies reporting on rising syphilis trends in high-income countries since the early 2000s.
"There is a clear relationship between sexual risk behaviour and the risk of syphilis and other sexually transmitted diseases," states Andrew Amato-Gauci, head of the ECDC program on HIV, STI and viral hepatitis. "The increases in syphilis infections that we see across Europe, as well as other countries around the world, are a result of several factors such as people having sex without condoms and multiple sexual partners combined with a reduced fear of acquiring HIV," Amato continues. "To reverse this trend, we need to encourage people to use condoms consistently with new and casual partners. Regular tests for syphilis and other sexually transmitted infections should also be part of the parcel, especially if there has been a risk of infection."
In addition, response measures should be informed by sound epidemiological data and targeted toward affected population groups taking into account the main determinants of transmission.
The response to syphilis outbreaks or programmatic control should include a combination of:
- case finding, including screening of at-risk groups, partner notification and surveillance activities, - case management with appropriate treatment following diagnosis,
- educational activities directed at the general population, those at-risk of syphilis infection, and at healthcare providers.
Congenital syphilis rates in the EU/EEA have been decreasing since 2005. During this time, rates of syphilis among women have decreased consistently in the EU/EEA, particularly in eastern Europe. This contributed to the reduction of the risk of mother-to-child transmission of syphilis in Europe that is in contrast to increasing congenital syphilis rates in many other parts of the western world. Despite this, underreporting of congenital syphilis is likely in several Member States of the EU/EEA and there is some concern regarding increasing syphilis rates among women in some western EU/EEA countries. Effective national antenatal screening programmes together with interventions to control syphilis transmission among heterosexual populations are key in order to sustain the low rates of congenital syphilis.
The diagnosis and treatment of syphilis are both accessible and cost effective. Left untreated, syphilis infection can lead to severe complications and also facilitates transmission of HIV infection. Untreated syphilis during pregnancy can severely compromise pregnancy outcomes, leading to fetal loss, stillbirth or congenital syphilis in the newborn.