Diphtheria

At a glance

Vaccine preventable – check who’s eligible
Vaccine included on the National Immunisation Program – check who’s eligible
Nationally notifiable disease

About diphtheria

Diphtheria is caused by toxin-producing Corynebacterium diphtheriae or, sometimes, Corynebacterium ulcerans bacteria.

It can:

infect the nose, throat and airways (respiratory diphtheria)
infect the skin (cutaneous diphtheria)
be carried in the body without causing symptoms.

Why it matters to public health

Diphtheria causes severe illness and death. Even with treatment, up to 1 in 10 people with respiratory symptoms die.

Before routine vaccination was introduced, diphtheria was a common cause of death in children.

Although it is now rare in Australia, diphtheria is common in many overseas countries and can be brought into Australia by returning travellers.

Diphtheria can spread easily in communities with low vaccination coverage. It still poses a risk for some communities, or for people travelling to places where the disease is more common.

Resistance to antibiotics is becoming more common for diphtheria. This means that infections are harder to treat. Detecting these infections is critical to prevent further spread of resistant strains.

Because of this, we:

monitor and report on cases in Australia
plan for how to manage outbreaks.

Symptoms

If you’re looking for advice about your own health or treatment options, see healthdirect or speak with a qualified healthcare professional. Our role is to provide public health advice – information and guidance that helps prevent disease, protect communities and improve wellbeing at a population level.

The type of symptoms depends on where the infection happens in the body – either the respiratory tract or the skin.

Respiratory diphtheria symptoms can include:

mild fever
a sore throat
malaise (feeling unwell)
loss of appetite.

Within a few days, a greyish-white membrane can form over the throat and tonsils to obstruct the airway. This can cause serious symptoms including:

difficulty swallowing
difficulty breathing
neck swelling.

The toxin made by the bacteria can cause myocarditis (inflammation of the heart) and paralysis. Without proper treatment, this can be fatal.

Cutaneous (skin) diphtheria symptoms include:

skin ulcers with a bluish appearance, often on the legs or arms
infection of pre-existing skin lesions.

Cutaneous diphtheria infections need wound management as they are slow healing and can become chronic if left untreated. These types of infections rarely cause the serious complications seen in respiratory diphtheria.

healthdirect’s symptom checker can help you decide whether to see a health professional.

Check your symptoms

Onset of symptoms

Diphtheria symptoms usually appear 2 to 5 days after infection.

How it spreads

Transmission of diphtheria usually occurs during close or prolonged contact.

Spreads between people can happen through:

respiratory droplets
secretions from the nose or throat
fluid from skin sores.

Some people carry the bacteria in their nose or throat without getting symptoms. These people can unknowingly spread the bacteria on to others and make them sick.

Although rare, the bacteria can spread from animals to people through:

consuming raw milk
close contact with livestock and domestic pets.

Infectious period

People are thought to be infectious from up to a week before symptoms start and for up to 6 weeks without treatment.

Antibiotics can shorten this period substantially.

Prevention

Get vaccinated

Vaccination is the best way to protect against illness and severe complications from diphtheria.

Multiple doses and booster doses are needed to produce and sustain immunity.

Vaccination is recommended for:

infants, children and adolescents as part of routine vaccination
routine booster vaccination in adults, including:
- pregnant people
- laboratory workers
- travellers to countries with limited access to health services
- older people
people who have missed doses of diphtheria-containing vaccine.

The diphtheria combination vaccine is free under the National Immunisation Program for children at 2 months, 4 months, 6 months, 18 months, 4 years, and 12 to 13 years through school-based vaccination programs. It is also free for pregnant people. If you are not eligible for a free vaccine, you can buy one from your healthcare professional or pharmacy.

Priority groups and settings

Some people are at greater risk of getting diphtheria or getting very sick from it.

If you are at greater risk, it is especially important to make sure you are fully vaccinated.

People at greater risk of severe disease

Diphtheria poses a greater risk of severe illness for:

young children
people who are unvaccinated or under-vaccinated.

People at greater risk of exposure

People are at greater risk of being exposed to diphtheria if they:

travel to countries where diphtheria is more common
are in close contact or live with someone who has diphtheria
live in crowded conditions
live or spend time in warm, humid areas, especially for cutaneous diphtheria
are laboratory workers who may be exposed to the bacteria.

Diagnosis and treatment

A healthcare professional can diagnose diphtheria by taking a swab from:

the throat or nose
fluid from skin sores.

You can use healthdirect’s directory to find a health service near you.

Find a health service

If diphtheria is suspected, treatment starts straight away.

Diphtheria is treated with antibiotics and antitoxin. People who have never, or not recently, been vaccinated will be offered vaccination.

Some people may be treated in hospital.

Read more about how to manage or treat diphtheria.

Surveillance and reporting

Diphtheria is a nationally notifiable disease – these are diseases that present a risk to public health.

Health authorities in each state and territory report new confirmed cases to us daily through the National Notifiable Diseases Surveillance System.

This is part of our surveillance activities, which help us monitor case numbers around the country and understand disease patterns.

We analyse the data and report on case numbers and other data through our data visualisation tool, where you can filter and search the latest information.

Outbreaks

How public health agencies respond to diphtheria cases and outbreaks depends on:

laws in each state or territory
local rules about reporting cases
what resources are available.

Public health units might respond to a diphtheria outbreak by:

advising infected people to avoid group settings such as work, school and childcare until they are no longer infectious
ensuring appropriate treatment for infected people
cover infected sores, if relevant
identifying and testing close contacts
ensuring preventive treatment or vaccination, if needed
providing information to people about the disease.

Read more about how the Australian Government defines and plans for outbreaks and pandemics.

Support

For information about diphtheria in each state or territory, see:

If you need mental health support, see a list of organisations, websites and services that offer support, counselling and information.

For travel advice, see Smartraveller.