Health authorities are urging people to get vaccinated, as a potentially deadly infection spreads across four Australian states.

Diphtheria is a serious infection caused by the toxin-producing bacteria, Corynebacterium diphtheriae. It spreads through contact with an infected person’s bodily fluids – such as droplets produced from coughing or sneezing – or skin sores.

Since January, Australia has recorded more than 220 diphtheria cases, in the worst outbreak the country’s seen in decades. As of Thursday, there were 139 cases in the Northern Territory, 82 in Western Australia, seven in South Australia and three in Queensland.

The federal government has announced a A$7.2 billion emergency support package, which aims to boost vaccination rates and strengthen the health workforce in states affected by the current diphtheria outbreak.

So is it still spreading? And should you be concerned?

Remind me, what is diphtheria?

There are two main types of this rare but serious bacterial infection.

Respiratory diphtheria affects the throat and airways, and can be life-threatening if the toxin produced by the bacteria damages the airways, nerves or heart. Even with treatment, up to 10% of people with respiratory diphtheria die.

Cutaneous diphtheria affects the skin, mainly causing skin ulcers on the legs or arms. This form of diphtheria is usually less severe, but contact with wounds is still a common way the infection spreads between people.

It is possible to contract respiratory diphtheria by being exposed to someone with........

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