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Is diphtheria contagious?

Page last updated 09 April 2020

Yes, diphtheria is highly contagious and is easily spread by coughing or sneezing. 

Without treatment, people with diphtheria are infectious for up to 4 weeks from the beginning of their symptoms. Some people can also become carriers and are infectious for longer.

Completing the immunisation schedule is important, as those who have not been fully immunised are at risk of developing the disease if they are exposed to the bacteria.


Sources & Citations

2. Victorian Government. Better Health Channel. Diphtheria. Available at: (accessed 27 February 2020).

10. The Australian Immunisation Handbook. Diphtheria. Available at: (accessed 27 February 2020).

SPANZ.SAPAS.18.04.0134(1)a - Date of preparation March 2020