Diphtheria Outbreak in Western Europe Linked to Migration Patterns

Thu 5th Jun, 2025

Recent findings published in a leading medical journal indicate that the significant diphtheria outbreak in Western Europe, which began in 2022 and affected numerous migrant populations, can be traced back to contamination that occurred during migration journeys or within European countries, rather than originating from migrants' home countries. This research underscores the importance of understanding the dynamics of infectious diseases among vulnerable groups.

The study, which involved collaboration among international researchers, including those from the Institut Pasteur and Santé publique France, reveals that the epidemic is the most extensive diphtheria outbreak in the region in the last 70 years. Researchers found that in 2022, 362 cases of diphtheria were documented across Europe, primarily affecting migrants. A series of rapid public health interventions, such as contact tracing and screening, helped mitigate the outbreak by the end of that year.

In 2023, further cases were reported in several countries, including Austria, France, Germany, and the United Kingdom, with a total of 123 cases recorded. Despite the decline in new infections, sporadic cases have emerged among migrant populations and other vulnerable groups, including the homeless, with a cumulative total of 536 cases and at least three fatalities since the outbreak began.

Researchers conducted a thorough analysis of 363 bacterial isolates from patients across ten European nations. The results showed that a striking 98% of those affected were male, with a median age of 18, and 96% had recently migrated to Europe. Most infections (77%) were cutaneous, while 15% were severe respiratory cases. The findings suggest that the source of contamination was likely during transit or at reception centers in Europe, rather than in the individuals' countries of origin.

Genomic studies revealed a strong genetic link between the bacteria responsible for the current outbreak and strains identified in earlier epidemics in Germany, indicating that the pathogen may have been circulating undetected within Western Europe. Public health experts emphasize the need for ongoing vigilance and enhanced support for diphtheria prevention among at-risk populations. This includes maintaining vaccination programs, conducting screenings, and ensuring access to healthcare services.

Prof. Sylvain Brisse from the Institut Pasteur highlighted the critical role of international collaboration in managing health crises, noting that the prompt sharing of genomic data between countries has facilitated a more coordinated response to the outbreak. As the situation evolves, health officials are advocating for increased awareness of diphtheria symptoms among healthcare providers, particularly those who interact with vulnerable populations.

Isabelle Parent du Châtelet, a unit manager at Santé publique France, reiterated the necessity of ensuring that vaccination records are current, especially for at-risk groups such as migrants, the homeless, and those with underlying health issues. She stressed that healthcare professionals should remain alert to the signs of diphtheria, especially in patients connected to these vulnerable communities.

This study is part of a broader initiative designed to monitor and control diphtheria cases in Europe, spearheaded by the European Center for Disease Prevention and Control (ECDC) and various public health organizations across the continent.


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