Toxigenic Corynebacterium diphtheriae Infections in Low-Risk Patients, Switzerland, 2023

Area of Science:

• Infectious Disease Epidemiology
• Microbiology
• Public Health

Background:

• Toxigenic Corynebacterium diphtheriae can cause outbreaks.
• Waning immunity and vaccination status are critical factors in disease susceptibility.

Purpose of the Study:

• To investigate a cluster of toxigenic Corynebacterium diphtheriae infections.
• To understand the transmission dynamics and implications for public health.

Main Methods:

• Genomic sequencing to identify related strains.
• Outbreak investigation and case finding.
• Review of vaccination status in affected populations.

Main Results:

• Identified genetically related toxigenic Corynebacterium diphtheriae strains.
• Linked infections to an outbreak among asylum seekers in Switzerland.
• Observed subsequent infections in patients with no known exposure to the initial outbreak.

Conclusions:

• Emphasizes the importance of rapid, interdisciplinary outbreak investigations.
• Highlights the need for regular assessment of vaccination status, especially in elderly individuals with declining immunity.
• Underscores the potential for infectious disease spread beyond initial exposed groups.