Australia is grappling with what health authorities are calling the country's largest diphtheria outbreak in decades. More than 220 cases have been reported across the Northern Territory, Western Australia, South Australia, and Queensland, prompting urgent vaccination drives and emergency funding. Federal Health Minister Mark Butler described the situation as 'very concerning,' noting it is likely the worst outbreak Australia has experienced in decades.
What is Diphtheria?
Diphtheria is a bacterial infection primarily affecting the throat and nose, but it can also infect the skin. The most dangerous form, respiratory diphtheria, creates a thick grey or white membrane in the throat that can obstruct breathing and swallowing. Toxins produced by the bacteria can damage the heart, nerves, and organs. Before routine vaccination, diphtheria was a leading cause of child mortality worldwide. Vaccines nearly eliminated it in wealthy nations, but immunity gaps have re-emerged.
How Does Diphtheria Spread?
The disease spreads through respiratory droplets from coughs, sneezes, or close conversation. It can also transmit via contact with open sores or contaminated objects. Both respiratory and cutaneous (skin) forms are circulating, with health officials particularly concerned about cases in remote communities where overcrowding, limited healthcare access, and uneven vaccination rates are common. Most recent infections have occurred in Aboriginal and Torres Strait Islander populations.
Symptoms of Diphtheria
Early symptoms resemble a cold: sore throat, fever, swollen neck glands, fatigue, hoarseness, and difficulty swallowing. The characteristic thick throat membrane may appear later. Severe cases can lead to heart inflammation, nerve damage, paralysis, or respiratory failure. Cutaneous diphtheria presents as painful sores, ulcers, or crusted wounds that heal slowly.
Why the Sudden Outbreak?
The primary driver is declining vaccination rates. The COVID-19 pandemic disrupted routine immunizations, leaving many children and adults behind on booster doses. Overcrowded housing, limited clinics, and stretched public health resources have facilitated spread. The Northern Territory leads with 133 cases, followed by Western Australia (79), South Australia (6), and Queensland (5). There is one suspected diphtheria death under investigation in a remote NT community, the first in nearly a decade.
Treatment and Prevention
Diphtheria is treatable with antitoxin to neutralize toxins and antibiotics to kill the bacteria. Severe cases may require intensive care for breathing support. Close contacts receive preventive antibiotics or booster shots. The best prevention is staying up-to-date with vaccinations, including boosters for adults. Health officials have launched mass vaccination clinics, public campaigns, and deployed extra resources to curb the outbreak.
