Syphilis 2018

Syphilis 2018

In 2018, the national monitoring scheme, stewarded by Statens Serum Institut (SSI), recorded 526 cases of syphilis in 524 persons.

A total of 444 (84%) of the cases occurred in 442 men and 82 (16%) in 82 women, as 2 men had two cases in the course of the year.

The median age was 39 years for men (range 16-88 years) and 29 years for women (range 16-60 years), Table 1.


A total of 311 (59%) of the cases, 257 men and 54 women, were reported to the Notification System for Infectious Diseases (NSID), the Department of Infectious Disease Epidemiology and Prevention (DIDEP). A total of 215 (41%) cases had not been notified to the NSID.

As in previous years, the majority of the patients resided in the Copenhagen area, Table 2.


The total number of cases registered in 2018 was somewhat lower than in the preceding year (545), Table 2. Thus, the increase observed for a number of years seems to have halted, Figure 1.

Congenital syphilis and syphilis in pregnant women

Among the 82 syphilis cases that were detected in women, 21 were found owing to the pregnancy screening, 11 hereof in cases not notified to the NSID. Twelve of the pregnant women were of Danish origin.


For the 215 syphilis cases who were recorded in 2018 but not notified to the NSID, mode and country of transmission are not known. The following thus only describes the 311 cases who had been notified to the NSID.

Among the 257 notified persons, 57 were men notified as heterosexual transmission cases (22% of all notified men), 186 were notified as men who have sex with men (MSM, 72% of the notified men); and in 14 cases, the mode of transmission was not stated (6% of the notified men). A total of 54 women were notified, all due to heterosexual transmission (17% of those notified). Figure 1 presents the number of persons notified with sexually transmitted syphilis since 2000.


Among the 308 cases in which origin was stated, 208 (68%) were of Danish origin, 84 (27%) were immigrants, 12 (4%) were second-generation immigrants and four (1%) were tourists. The number of persons who had not been born in Denmark totalled 84 from 37 different countries around the globe.

The country of transmission was stated for 283 (91%) of those notified, 232 men and 51 women. A total of 185 (80%) men and 46 women (90%) had become infected in Denmark. Among heterosexually infected men for whom the country of transmission was stated, 31 of 51 (61%) had become infected in Denmark, while this was the case for 145 of 169 (86%) of the MSM.

Among MSM notified as having become infected abroad, the most frequent countries of transmission were Spain, Germany and Thailand, whereas the most frequent country of transmission for men who were notified with heterosexual transmission abroad was Thailand.

Syphilis and HIV

Information about HIV status was available for 241 (94%) men and 47 women (87%)

Among HIV-tested men, 48 (20%) were HIV positives. There were 42 HIV positives among the 182 MSM (23%), five (10%) among the 49 men who were notified as heterosexually infected, and one (10%) among the ten men for whom sexual orientation was not stated. Among the 48 HIV positive men, two (4%) had been diagnosed with HIV and syphilis simultaneously, both of whom had become infected heterosexually, whereas 46 (96%) were known HIV positives prior to their current syphilis diagnosis (42 MSM, three heterosexual cases and one case for whom sexual orientation was not stated). Two women were notified as HIV positives, one was Danish, the other an immigrant.

This report is described in EPI-NEWS 34/19.