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Is diphtheria contagious?

Page last updated 13 January 2022

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

Without treatment, people with diphtheria are infectious for up to 6 weeks from the beginning of their symptoms. Some people can also become carriers and can infect a lot of other people.

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

1. Victorian Government. Better Health Channel. Diphtheria. Available at: (accessed 24 November 2021).

9. Australian Institute of Health and Welfare. Diphtheria in Australia. Available at: (accessed 24 November 2021).

MAT-AU-2102461  Date of preparation January 2022