An unvaccinated child off the north coast of New South Wales is in intensive care after catching respiratory diphtheria (throat diphtheria). A six-year-old child from close family contact is also infected.
These are the first cases of respiratory diphtheria in children observed in Australia since 1992.
What is diphtheria and how is it transmitted?
Diphtheria is a life-threatening infection caused by toxins produced by certain strains of Corynebacterium bacteria.
Respiratory diphtheria causes severe swelling of the throat and neck, which can block the airways and cause respiratory problems.
Bacterial toxin can also damage the heart, kidneys, brain and nerves. Bacteria can also cause sores on the skin, which are not as severe as respiratory diphtheria.
Diphtheria bacteria are transmitted through the respiratory droplets, for example, by coughing or sneezing. They can also spread through touching skin ulcers.
How is it prevented?
In Australia, diphtheria toxoid-containing vaccines (an inactivated form of the toxin) are provided free of charge to the National Immunization Program (NIP), with three doses initially at two, four, and six months of age.
These are six-in-one combined vaccines that also provide protection against whooping cough, tetanus, polio, hepatitis B, and Haemophilus influenzae type b (Hib) infection, which causes meningitis (inflammation of the lining of the brain) and sepsis. (blood poisoning).
Read more: Have you been vaccinated against diphtheria? Here’s why it’s important
Booster doses for diphtheria, tetanus, and whooping cough are provided under the National Immunization Program at 18 months, four years, and around 12 years (through schooled immunization programs). It is important to receive all of these booster doses, as immunity tends to decrease over time.
Reinforcements for adults are also recommended, but are not funded by the National Immunization Program.
How is it treated?
Antibiotics are given to people with diphtheria, but they may not have much impact on the disease once established.
Specialized treatment with diphtheria antitoxin (DAT) is often required to counteract the effects of the toxin. The DAT must be given at the beginning of the illness (within 48 hours).
However, there is a global shortage of DAT due to declining production over the past few decades.
He was once a great murderer
Diphtheria was once among the top ten causes of infant death. There were more than 4,000 diphtheria deaths in Australia between 1926 and 1935.
Diphtheria cases declined dramatically after the introduction of vaccines in the 1940s.
Respiratory diphtheria infection causes swelling of the throat and neck. Shutterstock
Diphtheria is now rare. Prior to the two recent cases in NSW, there had been no cases of respiratory diphtheria in children in Australia since 1992. 38 cases of cutaneous diphtheria were reported between 2011 and 2019, affecting both children and adults. During the same period, there were seven cases of respiratory diphtheria, all in adults. Two unvaccinated adults died of respiratory diphtheria in 2011 and 2018.
Why are we seeing diphtheria now? What role do travel play?
Anyone not vaccinated against diphtheria is at risk of getting the disease. Diphtheria vaccination rates in Australian children have been high, over 90% since 2000 and currently stand at around 95%.
People born before the year 2000 are more likely to be poorly vaccinated, as vaccination rates were lower when they were older.
Read more: Health Check: What Vaccines Should I Get As an Adult?
There is also a particular risk of traveling to countries where diphtheria remains more common, such as Southeast Asia, Papua New Guinea, former Soviet Union states, and Eastern European countries.
Diphtheria vaccination prevents the disease, but does not completely prevent people from carrying the bacteria in the back of the throat without symptoms. Fully vaccinated people can transmit the bacterium to unvaccinated contacts, even when they return from travel abroad.
Increases in diphtheria are now a real risk, as vaccination rates have declined globally.
We are also at greater risk of suffering from other diseases, such as measles, now international travel has resumed. Measles cases have increased globally in part due to the COVID pandemic-related disruption in routine immunization programs in many parts of the world. UNICEF and the World Health Organization have warned of a perfect storm of conditions for measles outbreaks.
A recent case of measles in a traveler was the first in Australia since March 2020.
What can you do?
It is key to ensure that people of all ages are up to date with their vaccines.
Parents should ensure that children receive all of their routine vaccinations on time; this will provide strong protection against serious diseases such as diphtheria and measles.
Vaccines provide strong protection against diphtheria. Shutterstock
People of all ages should also be up to date on vaccines, especially if they are traveling abroad. Beyond childhood, the Australian Immunization Handbook recommends a booster dose of diphtheria vaccine for:
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adults aged 50 and 65 years
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people of any age who are over ten years old since their last dose and who travel to a country where health services are difficult to access.
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people traveling to high-risk countries if more than five years have passed since the last dose.
Ensuring support for low- and middle-income countries, especially those in our region, to strengthen their immunization programs, even through measles and other vaccine recovery campaigns, is also key to protecting us all. .
Read more: Diphtheria could become a problem again thanks to new variants and antimicrobial resistance