Surge in diphtheria infections raises alarms across European health systems

Health officials are raising concerns after a major increase in diphtheria cases across the European Union (EU). Between 2016 and 2021, the EU reported an average of just 27 cases per year. But in 2022, that number suddenly jumped to 362 cases, prompting detailed investigations.

The majority of those affected were young men (98% male), with 96% being recent migrants. Unfortunately, vaccination status was unknown in 80% of the cases, making it hard to assess their protection against the disease.

Diphtheria is a serious bacterial infection, best known for affecting the throat, but it can also cause skin sores. In this outbreak, 78% of patients had skin-related (cutaneous) diphtheria, 15% had respiratory symptoms—including 3% with severe throat infections known as pseudomembranous disease—and 3% had both forms. There were 17 hospitalisations and one death.

Further testing revealed that 30 patients were also infected with Streptococcus pyogenes, a bacterium that can cause strep throat, and 15 had methicillin-resistant Staphylococcus aureus (MRSA), which is hard to treat.

Fortunately, most of the Corynebacterium diphtheriae bacteria (the cause of diphtheria) were still treatable with common antibiotics—98% were susceptible to penicillin and 94% to erythromycin. Genetic analysis showed that most infections came from three unrelated bacterial strains, suggesting people were infected during their migration journey or in overcrowded centres.

Health authorities stress the importance of early detection, hygiene, and vaccination to prevent further spread.

Source: New England Journal of Medicine