Diphtheria
There is a diphtheria outbreak happening in northern and central Australia. This is the largest outbreak since national reporting began in 1991. You can find affected areas on the Australian Communicable Disease Control (CDC) website. You can see current case numbers in the CDC epidemiology update reports.
No cases of diphtheria have been reported in the ACT to date.
On 22 May 2026, the Australian Government declared diphtheria a Communicable Disease Incident of National Significance (CDINS). The ACT Government is working closely with other jurisdictions and the Australian Government to monitor and respond to the situation.
In addition to the National Immunisation Program-funded vaccines, the ACT Government is funding a time-limited vaccination program for eligible people.
Diphtheria is a serious disease that can be prevented with vaccination. It is caused by bacteriaand can cause infections in the throat and airways (respiratory) or the skin (cutaneous).
Symptoms
Symptoms of diphtheria usually appear 2 to 5 days after exposure but can take up to 10 days.
The type of symptoms depends on where the infection is in your body.
You may have:
- a sore throat
- loss of appetite
- mild fever.
The bacteria can make a poison (toxin) in your body. This toxin can cause a greyish-white membrane to grow over the throat and tonsils. This can:
- make it hard to breathe
- make it hard to swallow
- cause swelling in the neck.
If the throat becomes blocked, it can be very dangerous.
The toxin can also inflame the heart, kidneys and nerves, sometimes causing long-term damage or death.
Diphtheria can also cause skin sores, often on the legs.
How it spreads
Diphtheria usually spreads in the air when an infected person coughs or sneezes.
You may also come in contact with diphtheria by touching:
- saliva, mucous or skin sores of someone with diphtheria
- contaminated objects or surfaces.
Although rare, it can spread from animals to people by consuming raw milk or through close contact with infected animals.
Infectious period
People can be infectious (potentially spread diphtheria) for up to 1 week before symptoms start and longer (up to 6 weeks) without treatment.
Treatment with antibiotic medications can help reduce the spread.
Diagnosis and treatment
A doctor can test for diphtheria by taking a swab from:
- your throat or nose
- fluid from skin sores.
Diphtheria is treated with antibiotics. People with severe infection may require hospitalisation and antitoxin medication.
If you have diphtheria, you should isolate from others until you are no longer considered infectious. A public health officer will advise on this. This helps to stop the disease spreading.
Because diphtheria spreads easily, contact tracing may be used to find people who have been in close contact with you and may be at risk of developing the infection. Contacts are provided with information about diphtheria, including symptoms to watch out for. They may also be recommended to be tested for diphtheria, receive a vaccine against diphtheria, or be provided with antibiotics.
Vaccination
Vaccination is the best way to protect yourself.
Vaccines against diphtheria are combination vaccines that also protect against other diseases, most commonly a vaccine that also includes protection for pertussis (whooping cough) and tetanus.
Several doses, including booster doses, are needed for long-term protection.
Vaccination for young people
Vaccinations for young people are included in the ACT immunisation schedule and are free.
Children should be vaccinated at 2 months, 4 months, 6 months, 18 months and 4 years.
Adolescents receive a booster vaccine in year 7 through the ACT High School Immunisation Program. If this vaccine is missed, talk to your general practitioner (GP) or pharmacist to get the free vaccine – a consultation fee may apply. Catch-up vaccines are free until 20 years of age.
Vaccination for adults
Diphtheria booster vaccines are recommended for:
- people travelling to high-risk areas overseas or outbreak-affected areas in Australia and their last dose was more than 5 years ago
- in each pregnancy (free vaccine during pregnancy)
- adults aged 50 years and older if their last dose was more than 10 years ago
- adults aged 65 years and older if their last dose was more than 10 years ago
- laboratory workers exposed as part of their job, every 10 years
- people travelling to countries where health services are difficult to access, if their last dose was more than 10 years ago.
Speak to your GP or pharmacist for more information and to see if a diphtheria vaccine is recommended for you. Recommendations depend on a person’s age, time since last vaccine and travel plans.
ACT time-limited diphtheria vaccination program
The ACT is implementing a time-limited vaccination program, with expanded booster recommendations and funding for eligible people, in response to the current diphtheria outbreak in northern and central Australia.
Eligibility for the ACT-funded diphtheria vaccination program includes all Aboriginal and Torres Strait Islander people aged 20 years and over who meet any of the following criteria:
- have not had a diphtheria vaccine in the last 10 years, or
- are travelling to an outbreak-affected area and have not had a diphtheria vaccine in the last 5 years, or
- are unvaccinated or need catch-up vaccination.
The free vaccine is available through General Practices (GP), including Winnunga Nimmityjah Aboriginal Health and Community Services. A consultation fee may apply.
If you are not eligible for a free vaccine, talk to your immunisation provider. Diphtheria vaccine is available for purchase through GPs and pharmacies.
More information
Diphtheria is a notifiable condition in the ACT.
For more information about diphtheria, contact your doctor or call (02) 5124 9213 to report a notifiable condition.
Read about reporting notifiable diseases in the ACT.