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.

What are the symptoms of diphtheria?

Diphtheria affects the mucous membranes, especially those of the upper respiratory tract and the skin.

“Classical” diphtheria is characterised by pseudomembranous pharyngitis. 

But it can also occur in other forms:

  • a runny nose with purulen and/or bloodyt discharge and pseudomembranes
  • pharyngitis resembling a streptococcal pharyngitis
  • forms affecting the skin and developing in ulcers, wounds, together with pseudomembranes.

Certain strains of bacteria responsible for diphtheria can produce a toxin that can spread in the body and reach, in particular, the heart and peripheral nervous system.

Symptoms occur within 2 to 5 days and up to 7 to 10 days after exposure to the bacterium. An infected person is contagious for 2 weeks after the infection. 

DID YOU KNOW? It is possible to be a carrier of the bacterium responsible for diphtheria without developing the disease. A healthy carrier can nonetheless be contagious and spread the bacterium, sometimes for months.

Pseudomembranous pharyngitis

“Classical” diphtheria is characterised by pseudomembranous pharyngitis. 

Pseudomembranes develop on the tonsils and uvula (small outgrowth at the back of the mouth in the opening of the throat). 

The pseudomembranes can sometimes clog airways and cause asphyxiation.

Pseudomembranous pharyngitis may be accompanied by swollen glands, which can be associated with inflammation and oedema of the surrounding tissues giving the appearance of a swollen neck also called “bull neck”.



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.

QR code

QR code for this page URL