Diphtheria - Annual Epidemiological Report for 2023

In 2023, 216 cases of diphtheria due to toxigenic Corynebacterium diphtheriae (n=155) or C. ulcerans (n=61) were reported to ECDC. The increase of diphtheria among migrants reported in several EU/EEA countries in the second half of 2022 decreased to lower levels in 2023. The highest proportion of C. diphtheriae cases was among 15- to 24-year-old males. C. ulcerans cases were more common in adults aged 45 years and above. Among C. diphtheriae cases with importation status available, 34% were reported as imported (having been outside the country of notification during the incubation period with no links to local transmission), with 78% of the imported cases presenting with a cutaneous infection.

Vaccination status was available for 44% of all cases. Sixty-seven percent of the cases with known vaccination status were not vaccinated or were vaccinated with an unknown number of doses. Vaccination with the diphtheria toxoid vaccine is the only effective method of preventing the toxin-mediated disease. Achieving and sustaining high vaccination coverage in the population is critical for preventing toxigenic diphtheria from causing serious or fatal illness.