Dr. Steph Williams

Hi, Norman.

Thanks for having me.

And Priya.

So the Australian CDC has been looking at this very closely.

And actually, just yesterday, on Friday, we published our weekly epidemiological update on the national diphtheria situation.

And what it shows is in the first five months of 2026, 248 diphtheria cases have been notified nationally.

That's to the end of May.

And that's compared to around less than 50 per year for all years before that.

And when you look at the epidemic curve, you can see that the cases really took off in March this year.

And this is happening in the Northern Territory, in areas of WA, in the Kimberley, including also some cases in the Pilbara and Goldfields, and more recently in northern parts of South Australia.

These are cases happening almost all entirely in Aboriginal communities, in remote and very remote areas, and in young adults.

So the scale is unusual.

This is a really interesting question because, you know, the role of epidemiologists is always to, you know, try and figure out who, where, what and why, why now.

When we look at the types of diphtheria that are being caused in this current outbreak, around two-thirds of all of the cases that we've seen are the skin version, the cutaneous infections typically associated

through non-healing wounds.

And about one third are the respiratory types, so the bacteria causing an infection, sore throat, etc.

Those proportion of cases are relatively consistent week to week.

What we are seeing is about 20% or a quarter of them requiring some form of hospitalisation, whether that be for public health management or infection control.

And sadly, we have seen one reported case in the Northern Territory where diphtheria has been seen as a probable cause of death, and that was in April 2026.

To your question of under-reporting, we know diphtheria is, it can cause outbreaks.