Diphtheria is an infection caused by bacteria. It mainly affects the nose and throat, but can also affect the skin. It is very infectious and can become serious very quickly. Most cases occur in people who have never had a diphtheria vaccine, or who did not complete the initial course.


Fever, sore throat, difficulty swallowing, loss of appetite, hoarse voice. Serious cases can lead to breathing problems and heart failure.

How do you catch diphtheria?

Diphtheria is mostly spread by coughs and sneezes, but there are other ways it can be spread, including by eating unpasteurised dairy products.

Incubation period

2 – 5 days


Diphtheria is diagnosed by sending swabs from the mouth and throat to a laboratory for testing.


A course of the vaccine combining diphtheria with tetanus and polio is offered routinely in the UK from the age of 8 weeks. A booster vaccination may be advised for travellers going to areas of high risk.


As diphtheria can be very serious, patients will be isolated in hospital and started on antibiotics before swab test results are received.