Key facts

Smallpox is a highly infectious disease caused by the variola virus. The World Health Organisation declared smallpox eliminated from the world population in 1979.

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What is smallpox?

Smallpox is a highly infectious disease caused by the variola virus. The disease has been eradicated globally since 1979.

What are the symptoms of smallpox?

A person with smallpox would have typically presented with:

  • fever
  • headache
  • muscular ache or pain, particularly in the back
  • rash that develops into sores, pustules (raised, firm lumps), then scabs and scars.

Smallpox infection would cause severe disease or death.

The time between exposure to the virus and getting sick was usually 7 to 17 days.

How does smallpox spread?

Smallpox only affects humans. It can spread from one person to another through:

  • droplets from the nose or mouth of someone who has smallpox when they cough or sneeze
  • direct contact with fluid found in an infected person’s sores
  • direct contact with contaminated objects, such as bedding or clothes.

The virus can’t survive on surfaces or objects for more than 48 hours.

Who is at risk of smallpox?

No one is at risk of catching smallpox in Australia.

There is a small risk that bioterrorism (a deliberate release of the virus) could cause new cases of smallpox, but this is extremely unlikely.

How is smallpox prevented?

ACAM2000 is a vaccine that can be used against smallpox, but it is not commonly available.

The ACAM2000 vaccine is a “live” vaccine made from the vaccinia virus, which is like the variola virus that causes smallpox, but is less harmful. The vaccination site must be cared for to prevent the spread of the vaccinia virus to yourself or others. A person cannot develop smallpox from getting the vaccine. The vaccine provides immunity for a very long time.

Another vaccine, JYNNEOS, can also provide protection against smallpox but is not routinely used for smallpox prevention.

Vaccination is not usually recommended because smallpox is not likely to be seen in Australia again.

In the event of a smallpox outbreak, people exposed to someone with smallpox may be recommended to get the vaccine, so that they don’t get infected.

What is the public health response?

Any case of smallpox represents a public health emergency. Doctors, hospitals, and laboratories must immediately notify the local public health unit of any suspected cases.

Current as at: Wednesday 4 March 2026