Cases in WA spike as Australia’s diphtheria outbreak worsens

Doctors working in certain parts of Western Australia are eligible to receive an extra diphtheria booster as cases across the Kimberley region and the Northern Territory continue to grow.

Experts have said it is no longer an isolated outbreak as NT authorities investigate a potential death from the contagious bacterial infection and Health Minister Mark Butler decribed it as likely the biggest diphtheria outbreak seen in Australia in decades.

The Minister confirmed NT authorities were still investigating the reported death and were yet to officially record it as a diphtheria death.

According to the National Notifiable Disease Surveillance System, 223 cases have been recorded in Australia in 2026, (as pictured above) with 133 of those in the NT and 79 in Western Australia.

Minister Butler said Aboriginal medical services were “deeply, deeply concerned” as “almost all of the cases” have been in Indigenous Australians.

Dr Milena Dalton head of Immunisation and Health Systems Strengthening at Burnet Institute said the outbreak was no longer isolated to one area.

“It highlights how quickly vaccine-preventable diseases can re-emerge when there are immunity gaps. 

“Diphtheria remains rare in Australia because vaccination works.

“But this outbreak is a reminder that rare does not mean impossible, and that protection needs to be maintained through timely boosters for adolescents and adults."

She said the most important message for health professionals and the public was that diphtheria is preventable.

“Vaccination and boosters remain our best protection against severe disease, hospitalisation and death, and they are especially urgent in communities where people face barriers to healthcare,” Dr said

 “The fact that this outbreak is affecting Aboriginal communities points to the need for a rapid and culturally safe public health response."

Children and adolescents receive a diphtheria vaccination as part of the childhood immunisation scheduled and adults aged 50 years are urged to receive a booster if they have not had one in the previous 10 years. 

Due to the outbreak in regional WA, Aboriginal and non-Aboriginal people living in the Kimberley, Pilbara or Goldfields regions are eligible for a booster vaccine if it has been more than five years since their last dose.

Eligibility also extends to people with regular direct contact with Aboriginal communities and patient-facing healthcare workers in these regions.

GPs are also advised to follow up and offer vaccines to children and adolescents eligible under the National Immunisation Program, who are not up to date with their scheduled diphtheria-containing vaccines.