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Diphtheria: Symptoms, Prevention and How Doctors on Demand Can Help

Diphtheria in Australia in 2026 | How telehealth can help

Disclaimer: This information is not a substitute for professional medical advice, diagnosis or treatment.

What is diphtheria?

Diphtheria is a serious and highly contagious bacterial infection caused by Corynebacterium diphtheriae or Corynebacterium ulcerans. It primarily affects the nose and throat, but can also infect the skin¹.

The bacteria produce a toxin that can cause severe complications, including airway blockage, heart damage, nerve damage, and in severe cases even death¹.

Although rare in Australia due to strong vaccination programs, diphtheria has not been eradicated and can resurface, particularly when immunity declines³.

Symptoms of diphtheria

Symptoms typically appear 2–5 days after infection and can worsen quickly if untreated².

Common symptoms may include:

Sore throat and mild fever
Swollen glands in the neck
Difficulty swallowing or breathing
A thick greyish membrane at the back of the throat
Skin ulcers or sores

In severe cases, the bacteria can lead to:

Heart inflammation (myocarditis)
Nerve damage or paralysis
Death (up to 1 in 10 respiratory cases)

Diphtheria outbreak in Australia

Australia is currently experiencing one of its largest diphtheria outbreaks in decades, with cases rapidly increasing across multiple states and territories⁴.

Over 130 cases reported in the Northern Territory alone
Additional cases recorded in Western Australia, South Australia and Queensland
Nationwide cases have exceeded previous yearly totals, with 2026 already surpassing 2025 figures⁵

Why is it happening?

Health experts link the outbreak to:

Declining vaccination and booster uptake
Reduced immunity in adults
Healthcare access challenges in remote regions

Notifications have also been increasing since late 2025, signaling a sustained public health concern.

Reduce your risk of diphtheria

Diphtheria is vaccine-preventable, and vaccination remains the most effective protection.

In Australia

The diphtheria vaccine is given in combination vaccines (e.g., dTpa: diphtheria–tetanus–pertussis).

Children receive routine doses under the National Immunisation Program
Adults should receive booster shots every 10 years (or every 5 years in higher-risk settings)⁶

During the current outbreak, authorities are urging:

Catch-up on any overdue booster vaccinations
Undertake immediate testing if symptoms develop

When to see a doctor

You should seek medical advice immediately if you experience:

Persistent sore throat or fever
Difficulty breathing or swallowing
Unusual or non-healing skin sores

Early diagnosis and treatment are recommended to help prevent complications and stop transmission.

How Doctors on Demand can help

During an outbreak, fast, convenient access to medical care is essential—and that’s where telehealth services like Doctors on Demand play an important role.

Speak to a GP 24/7

With Doctors on Demand telehealth appointments, you can connect with an Australian-registered doctor anytime, day or night for advice on symptoms, testing, and next steps.