[Two children in the Netherlands with a Corynebacterium diphtheriaeinfection].

Infections with <i>Corynebacterium diphtheriae</i> were virtually absent among the Dutch population due to vaccination, while in the first half of the 20th century, it was a significant cause of child mortality. However, due to imported infections resulting from migration from countries with low vaccination coverage, infections with <i>Corynebacterium diphtheriae</i> are resurging. Concurrently, the vaccination rates among Dutch children are decreasing, elevating the risk of outbreaks. Severe symptoms are caused by exotoxins from the <i>C. diphtheriae</i>, infections with non-toxigenic strains can occur, which vaccination does not protect against. The bacteria itself is rarely invasive; only the toxin spreads. Non-toxin-producing strains manifest locally with milder symptoms but can become invasive, causing bacteraemia and endocarditis. As infections with non-toxigenic strains are not notifiable, little is known about their epidemiology. Moreover, specific culture media are required for bacterial cultivation, potentially leading to missed diagnoses.