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Is diphtheria making a comeback? Here are the latest figures and what can be done

The team of doctors and fact-checking experts from the National Medical Association addresses the main health-related concerns

28 August 2026

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4' min read

Translated by AI

Versione italiana

Key points

But what causes diphtheria?
But aren’t there any treatments for diphtheria?
But in which parts of the world is diphtheria still found?
But what can be done?

4' min read

Translated by AI

Versione italiana

Until recently, diphtheria was a disease that had almost been forgotten. In the last century, in fact, thanks to the mass vaccination of infants in their first few months of life, the number of cases recorded in Italia and other high-income countries had plummeted to just a handful per year, mostly due to infections contracted abroad, in areas with inadequate healthcare services, where vaccination coverage is insufficient.

Recently, however, there has been a resurgence even in developed countries. And in August 2026, Italia too had to report the first death from diphtheria since 1991, in a 4-year-old girl from Palermo.

But what causes diphtheria?

The causative agent of diphtheria is primarily a bacterium, *Corynebacterium diphtheriae*, which can colonise the skin or the upper respiratory tract, even without causing the disease. There are therefore healthy carriers who, without realising it, pass the bacterium on to others, mostly via droplets of saliva emitted when speaking or coughing.

The bacterium itself is harmless until it becomes infected by a virus: this provides it with the genetic instructions needed to produce the toxin responsible for the disease. When a toxin-producing strain infects a susceptible individual, symptoms appear after two or three days, initially resembling those of severe tonsillitis, with fever, a sore throat and swollen lymph nodes. In the most severe cases, the toxin causes cellular damage that can lead to the formation of characteristic greyish pseudomembranes, consisting of bacterial residues, cells and other substances. In the throat, these pseudomembranes can act as a barrier or, if they detach, cause bleeding, thereby hindering swallowing and breathing, and potentially leading to death by suffocation.

Furthermore, the toxin can also spread to the rest of the body via the bloodstream, affecting other vital organs – particularly the heart and the nervous system – with the risk of complications such as myocarditis, arrhythmias, heart failure, paralysis of the soft palate, peripheral neuropathies and eye disorders, even after recovery from the acute phase.

But isn’t there a treatment for diphtheria?

As we explained here, mortality from diphtheria began to decline in Italia and in all the wealthier countries even before vaccines became available. The improvement in treatment was due to the introduction of horse diphtheria serum, containing the antidote to the diphtheria toxin, and to the discovery of antibiotics, which combated the bacterium capable of producing it. However, treating a serious illness is not the same as preventing it: the serum must be administered in the early stages of the infection, before the toxin is produced, and can cause very dangerous adverse reactions; antibiotics are useful for stopping the spread of the bacterium, but they are powerless against the action of the toxin itself once it has been released into the body. Even those who, thanks to these treatments or to a tracheotomy – which, as we explained here, prevented suffocation – survived the ordeal of the disease still had to face a long period of recovery. The vaccine, on the other hand, induces antibodies that neutralise the diphtheria toxin as soon as it first appears in the body, preventing it from causing serious tissue damage. Even if the infection presents as a sore throat, in vaccinated children it clears up within a week without complications.

But in which parts of the world is diphtheria still present?

Despite the availability of an effective vaccine, none of the six macro-regions into which the World Health Organisation has divided the globe is completely free of diphtheria cases. In 2025, only 85 per cent of the world’s children had completed the primary series of three doses required for basic protection, and an even smaller proportion of children and adults were up to date with their booster doses, which should be administered during school age and then every ten years in adulthood.

In recent years, reports have also increased in high-income countries. In Europe, between January 2023 and early 2025, 234 cases of diphtheria were recorded, whereas between 2009 and 2020 there were only around 20 cases each year. The phenomenon appears to be concentrated amongst the most socio-economically vulnerable populations; consequently, as early as July 2025, the European Centre for Disease Prevention and Control (ECDC) recommended that health authorities focus their efforts on protecting these high-risk groups: homeless people, migrants and people who use drugs.

The country with the highest number of cases in 2024 was Germany: among the 55 cases reported that year was an unvaccinated school-age child, who subsequently died in January 2025 after three months in intensive care.

The situation is even worse in Australia, where an outbreak of diphtheria unprecedented in recent decades is currently taking place: between 1 January and 10 August 2026, 513 cases have already been diagnosed, with one death. In this case, the infection has affected, rather than unvaccinated children, young adults from Aboriginal and Melanesian communities who are socio-economically and medically disadvantaged, malnourished, have underlying health conditions, live in overcrowded conditions and had not received the recommended booster doses.

But what can be done?

As well as seeking to reach those who have never been vaccinated and undertaking health promotion activities targeting the population groups most at risk, the ECDC report recommends raising awareness amongst doctors, so that they once again bear the disease in mind and recognise it when they encounter it, and health authorities, so that, on the one hand, they carry out careful epidemiological surveillance and, on the other, ensure they have emergency stocks of diphtheria antitoxin available.

At the heart of it all, however, dialogue between families, paediatricians and public health professionals remains essential. Only this can build a relationship of trust, which is the only effective means of combating the misinformation about vaccines that puts our children at risk.

Read the full article on the dottoremaeveroche website, run by Fnomceo