UNICEF and the World Health Organization (WHO) agree that childhood immunization is one of the most powerful and cost-effective public health interventions. In 2015, more than 116 million infants, 86 per cent of the global infant population, presented for immunization treatment with a DTP3 vaccine. DTP3 offers protection against the often-fatal consequences of contracting diphtheria, tetanus and pertussis (whooping cough) and averts an estimated two to three million infant deaths every year. These figures make it difficult to argue with Stanley Plotkin's assertion that with the exception of clean water, no other modality, not even antibiotics, has had such a major effect on global mortality reduction and population growth. In Ireland, 96 per cent of parents present children for immunization treatment to protect them against the ravages of formerly rampant diseases such as diphtheria, measles, mumps, pertussis (whooping cough), polio, rubella (German measles), tetanus, tuberculosis, haemophilus influenzae B (Hib), hepatitis B, meningococcal C (Men C), and pneumococcal disease. In common with most countries, the childhood immunization programme in Ireland was founded on the public health response to diphtheria. This successful intervention ensured that Ireland has remained diphtheria free for almost 50 years. This is a significant achievement considering diphtheria continues to appear annually in many European states, albeit in much reduced numbers than in former years.

Prior to the mass social acceptance of childhood immunization in the 1940s, diphtheria was one of the most prolific child killers in history. The formation of a leathery membrane in the lower airways induced death by suffocation and earned diphtheria the moniker ‘strangling angel of children’. It showed scant regard for social status and infiltrated Europe's royal palaces as sinuously as her slums and hovels. For parents and children in nineteenth and early twentieth-century Ireland, diphtheria represented the ‘most dreaded disease of childhood’, but for their modern-day counterparts, diphtheria has been relegated to a somewhat obscure disease. Few Irish doctors have seen a case of diphtheria, let alone treated one. In Ireland, diphtheria has been consigned to history, and so too have the horrors and mass fatalities once associated with it. But how was this achieved? Was active immunization received with open arms by public health authorities, the wider medical community, and the general public?