Background: Since 2001, laboratories are required to notify syphilis diagnoses anonymously in Germany, physicians complement clinical information. Between 2010 and 2019 the number of syphilis cases increased by 95%. We analyzed syphilis surveillance data from 2019 to June 2022 to assess the current dynamics with special regard to the COVID-19 pandemic in order to initiate appropriate prevention measures.
Methods: Potential double notifications were identified. We analyzed syphilis cases by year of diagnosis, sex, area of residence, and transmission route.
Results: Overall, 7,398 (-7% compared to 2019) and 6.716 cases (-9% compared to 2020) were reported in 2020 and 2021 respectively. From January to June 2022, the number of cases increased by 17% compared to this period in 2021. Overall incidence in 2021 was 8.1/100,000 inhabitants, with highest incidences in metropolitan cities as Cologne (37.7), Berlin (34.3), and Munich (27.3) and Frankfurt/M. (24.3).
Men accounted for 94% of cases in 2020 and 2021. 86% (84%) of cases with information on transmission route were men who have sex with men (MSM) in 2020 respectively 2021, 14% (16%) heterosexuals. HIV-coinfection was reported for 42% (38%) of MSM and 8% (7%) in heterosexuals. Cases of MSM decreased by 10% in 2021, heterosexually transmitted cases increased by 4%, compared to 2020. Incidence decreased in 13 of 19 larger cities having an incidence >15 cases/100.000 inhabitants in 2021. During national lockdowns we observed a drop of cases in MSM, but no subsequent rise (fig. 1). The proportion of cases with primary or secondary stage of syphilis in MSM did not change between 2019 and 2021.
Conclusion: Data showed a high burden of disease in MSM in metropolitan cities. Reported incidence dropped in MSM during the pandemic without subsequent rise. Information on sexual behavior is not available from notification data. However, the unchanged proportion of early stages of disease suggests that the incidence decreased due to a decreased number of sexual encounters in MSM, as a consequence of temporarily reduced contacts during lockdowns rather than by less available testing and treatment facilities.
