Risks and Severity

In the past diphtheria was a major cause of death among children. Thanks to widespread vaccination in Belgium since 1959, diphtheria has almost disappeared from our country. But the bacteria are still in circulation and vaccination is the only way to prevent diphtheria.

Serious complications related to the diphtheria toxin

Certain strains of Corynebacterium bacteria can secrete a toxin that, when it spreads, especially in the heart and nervous system, can cause serious complications: myocarditis, peripheral paralysis, etc. 


The severity of diphtheria is also related to the production of pseudomembranes observed in “classical” diphtheria: this is known as pseudomembranous pharyngitis.

These pseudomembranes develop on the tonsils and the uvula (small outgrowth at the back of the mouth in the opening of the throat) and can clog the airways and cause asphyxiation.

In the case of cutaneous diphtheria, pseudomembranes can also develop on wounds and ulcerations. 


In 5 to 10% of cases, even if it is treated, diphtheria can cause death.

When the disease is not treated, it can be fatal in 50% of cases. 



Sciensano performs epidemiological surveillance of diphtheria and other vaccine-preventable diseases. Sciensano centralises and analyses data provided by various partners and also coordinates certain studies or surveillance networks. Accordingly, it can observe the “trends” (figures) for diseases such as diphtheria.

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