Background: Subsequent to detection of a non-travel associated cluster of mpox cases in the United Kingdom in early May 2022, laboratory confirmed cases of the notifiable infection were also reported in Germany.
Methods: We analyzed mpox notification data by dates of diagnosis and symptom onset, sex, age, hospitalization status, probable route of transmission, and probable place of infection (PPOI).
Results: By 31 December 2022, 3,676 cases were reported: Median age was 37 years (range 0-85, including six cases < 18 years), 99.4% were male. For 93.9% of 798 cases with data on the probable route of transmission, sexual contact between men was reported. Of 3,250 cases with data on hospitalization, 6.3% were hospitalized; no deaths were reported. Median incubation period of cases having a confirmed exposition period of one day (n=264) was 7 days; for 25% of these the incubation period was < 5 days.
The first case was notified on 20 May, earliest symptom onset reported was 2 May. Of cases with symptom onset before 22 May, for 27/54 the PPOI was abroad (fig. 1), often during travel-associated gay pride events. From 23 May onwards, 88.8% cases with data on PPOI (n=2,610) were acquired in Germany. For 58.6% of cases acquired in Germany, Berlin was reported as PPOI, 9.9% of those were not residents of Berlin.
Following a sharp increase in cases until early July, case numbers decreased substantially until early October (fig. 1).
Conclusion: Germany has been one of the most affected countries in this outbreak, with the sixth highest overall number of mpox cases worldwide. After initially comprising mostly travel-associated cases, the outbreak shifted to predominantly autochthonous transmission mainly among MSM. There had been circulation in Berlin already prior to outbreak recognition.
The city state of Berlin, the outbreak’s epicenter in Germany, has one of Europe`s largest MSM populations and is a major international MSM hotspot with many gay clubs and sex-on-premises locations. Intense prevention measures were implemented on national and state level. Close cooperation among a broad range of public health professionals, clinicians, and MSM community organizations provided non-stigmatizing, targeted information and vaccination offers.
