Image showing the diphteria virus

Diphtheria: history and prevention

Diphtheria is caused by a bacterium called Corynebacterium diphtheria and is transmitted in respiratory droplets.

Diphtheria infects the respiratory tract where it can cause sore throat, fever and swollen glands. The bacteria make a toxin that kills healthy tissue in the respiratory system with the dead tissue covering the nose, tonsils and throat, making it very hard to breathe and swallow.

Diphtheria was once a highly significant illness and a major cause of death, particularly in children. Diphtheria infection has a 20% mortality rate if the infected person is either under 5 or over 40. This mortality rate drops 10% if the infected person is aged between 5 and 40. The United States recorded 206,000 cases of, and 15,520 deaths from, diphtheria in 1921.

In 1948, 521 cases of diphtheria were reported in Ireland. Due to the introduction of the combination diphtheria/tetanus/pertussis (DTP) vaccine in 1952/1953, the case numbers declined progressively until none were reported in 1968. After a gap of nearly 50 years, one case was reported in 2015 and another in 2016. No cases of diphtheria have been reported in Ireland since 2016.

Johnny ‘Chris’ Kelleher’s account of how he came into a career in newspaper selling starts with a tale of devastating familial loss, and mentions the death of one of his mother’s first two sons from diphtheria in 1924.

Content log of this extract (the full transcript can be accessed here in the item entry): tell me a little bit about your family – my mother was married twice – Freddie Murphy was a newspaper ‘shopper’ – he died in 1924, a young man, with TB – better known as consumption – if you got the TB it just consumed you – he died at the age of 24 – left my mother with four children – no welfare – she had to go out selling newspapers to rear the four of them – he died in February ‘24, she buried one of the boys in June 1924 and she buried the other boy in September 1924 – diphtheria and the croup – left with the two girls – met my father – she kept on the papers – till the last day of her life.


Anon (2021). Diphtheria – Health Protection Surveillance Centre. [online] Available at: <> [Accessed 8 December 2022].

Epidemiology and Prevention of Vaccine-Preventable Diseases, 11th Edition (The Pink Book). National Immunization Program, Centers for Disease Control and Prevention.

Pinkbook: Diphtheria | CDC (2021). Available at: [Accessed 8 December 2022].


UCC Historian Michael Dwyer has extensively researched the history of diphtheria in Ireland, and his book, Strangling Angel: Diphtheria and Childhood Immunization in Ireland, argues that it was likely to have been more common that was reported, and traces childhood vaccination initiatives in the Irish state.

Dwyer, M. (2018) Strangling Angel: Diphtheria and Childhood Immunization in Ireland. Reappraisals in Irish History. Liverpool: Liverpool University Press.