Smallpox

At a glance

Vaccine preventable – check who’s eligible
Nationally notifiable disease

About smallpox

Smallpox is a serious disease caused by the variola virus.

It is similar to the virus that causes mpox.

Smallpox no longer occurs anywhere in the world.

Why it matters to public health

Smallpox is one of the deadliest communicable diseases. It is also highly contagious.

The World Health Organization (WHO) declared smallpox eradicated in 1980 following its Smallpox Eradication Program.

Before then, millions of people around the world died from smallpox. People who survived were often left with permanent complications, including severe scarring.

Australia’s last smallpox case was in 1938.

Today, people could only be exposed to smallpox if the virus was misused in an act of bioterrorism or biocrime. The Australian Government regulates handling of the virus to minimise this risk.

Only 2 secure laboratories in the world keep the virus for research. Australian laboratories do not store it.

Symptoms

If you’re looking for advice about your own health or treatment options, see healthdirect or speak with a qualified healthcare professional. Our role is to provide public health advice – information and guidance that helps prevent disease, protect communities and improve wellbeing at a population level.

Common initial symptoms include:

After a few days, a rash of fluid-filled blisters develops in the mouth and spreads all over the body. These blisters crust over and form scabs.

Complications of infection include:

severe scarring from the scabs
low blood pressure
blindness
pneumonia
arthritis and joint deformities
bone infections
encephalitis
multi-organ failure
death.

Read more about the symptoms, diagnosis and treatment of smallpox.

Onset of symptoms

Initial symptoms usually start between 7 and 19 days after getting infected. The rash then develops 2 to 3 days later.

How it spreads

Smallpox spreads between people through:

respiratory droplets that spread through the air when a person with smallpox speaks, coughs or sneezes
contact with the fluid from smallpox blisters
contact with surfaces or objects contaminated by bodily fluids or respiratory droplets.

Infectious period

People with smallpox are infectious from when the fever starts. They are most contagious once the rash develops and for about 7 to 10 days afterwards.

Prevention

Smallpox vaccination is no longer routinely given.

Vaccination is recommended for laboratory workers who work with smallpox-related viruses.

Some smallpox vaccines are used to prevent mpox.

Priority groups and settings

There is currently no risk of smallpox.

People at greater risk of severe disease

Smallpox would pose a greater risk of severe disease for:

people who are immunocompromised
children
pregnant people.

People at greater risk of exposure

Only laboratory staff who work with variola virus are at risk of exposure.

Diagnosis and treatment

Smallpox can be diagnosed through a test using samples of:

blister fluid
scabs
blood.

Anyone with smallpox would be isolated and treated in a hospital designated to manage dangerous infectious diseases.

There is no specific treatment for smallpox.

Read more about how to manage or treat smallpox.

Surveillance and reporting

Smallpox is a nationally notifiable disease – these are diseases that present a risk to public health.

Because of how serious it can be, smallpox is a listed human disease. This means the Australian Government can use special powers to respond quickly if it’s detected.

Outbreaks

It would only take one person with suspected smallpox to trigger an outbreak response.

Australia keeps an emergency supply of smallpox vaccine to use in case of an outbreak.

Read more about how the Australian Government defines and plans for outbreaks and pandemics.

Support

For information about smallpox in your state or territory, see:

If you need mental health support, see a list of organisations, websites and services that offer support, counselling and information.