Smallpox, also known as variola, is a contagious and deadly virus with no cure. But worldwide vaccination efforts have eradicated it.

Since the time of ancient Egypt, smallpox has proven to be one of the most devastating diseases to humankind. Widespread smallpox epidemics and their associated death tolls fill the pages of history books.

The first smallpox vaccine was created in 1796. However, the disease continued to spread on a widespread basis for another 200 years. The World Health Organization (WHO) implemented a strict vaccination standard in order to slow the infection rate. The last known case in the United States occurred in 1949 and the last known natural case worldwide occurred in 1977 in Somalia.

By 1980, the WHO declared that smallpox had been completely eradicated, although government and health agencies still have stashes of the smallpox virus for research purposes.

Currently, research around smallpox is focused on vaccines, drugs, and tests for diagnosis in the event that it is used as a biological weapon. Vaccines for smallpox may offer protection from other diseases, including mpox (formerly known as monkeypox).

Keep reading to learn about the symptoms and types of smallpox and the vaccines available.

Smallpox causes different symptoms depending on the phase of the illness. Phases and associated symptoms include:

Incubation period

Historical accounts show that when someone had the smallpox virus, they had no symptoms for between 7 and 19 days. The virus was not contagious during the incubation period.

Early symptoms

Once the incubation period was over, the following flu-like symptoms occurred:

  • high fever
  • chills
  • headache
  • body aches
  • vomiting

These symptoms lasted about 2 to 3 days. The virus would be highly contagious during this time.

Early rash

Just as the patient started to feel better, a rash would appear. The rash started on the face and then spread to the hands, forearms, and the main part of the body.

The virus would be contagious until the rash disappeared.

Pustular rash

Within two days of appearing, the rash would develop into bumps filled with pus (abscesses). The pustules would break open and scab over.

Scabs

The scabs would eventually fall off, leaving pit mark scars. Until all the scabs fell off, the virus remained contagious.

People no longer receive routine smallpox vaccinations. While most people had only mild side effects, the smallpox vaccine can have potentially fatal side effects, so only people at high risk of exposure get the vaccine.

People more likely to develop serious reactions can include:

People in these groups typically only received the vaccine if they had been exposed to smallpox. Prompt treatment may also help reduce side effects.

As a result of worldwide, repeated vaccination programs, the smallpox virus has been completely eradicated. The only people considered to be at risk for smallpox are researchers who work with it in a laboratory setting.

The vaccine is known for causing a telltale scar.

Doctors may also recommend the smallpox vaccine to prevent mpox in people at a high risk.

There were four types of smallpox. They included:

  • Variola minor: A common, but less fatal type of smallpox. A 2021 review of research estimates that less than 5% of those infected died.
  • Variola major: A more common and deadly type of smallpox. The same review estimates that 30% of cases were fatal.
  • Hemorrhagic smallpox: A rare and deadly type of smallpox that causes organs to leak blood into the mucous membranes and skin.
  • Malignant smallpox: A rare and deadly type of smallpox where smallpox lesions did not develop into pustules or pus-filled bumps on the skin. Instead, they remained soft and flat throughout the entire illness.

The smallpox virus is contagious from the time symptoms develop until all of the scabs fall off.

It can spread though:

  • contact with bodily fluids of a person with smallpox
  • airborne spread via saliva droplets when a person with smallpox coughs or sneezes
  • sharing clothing or bedding with a person with smallpox

While there is is no cure for the smallpox virus, antiviral treatment may reduce symptoms and severity. Options may include:

  • tecovirimat, an FDA-approved treatment
  • cidofovir, which has approval for use during an outbreak
  • brincidofovir, an FDA-approved treatment

In the unlikely event that exposure to the smallpox virus occurs, vaccination within 1 to 3 days can also keep the illness from being so severe. In addition, antibiotics may help to reduce the bacterial infections associated with the virus.

Doctors may also prescribe smallpox drugs for mpox.

The following includes frequently asked questions about smallpox.

Does smallpox still exist?

Smallpox has been eradicated worldwide, though samples still exist in two approved research laboratories in the United States and Russia. The United States also has enough smallpox vaccines for the entire United States population.

Do many people still get smallpox today?

Smallpox has been successfully eradicated worldwide due to vaccination efforts. There are currently no cases circulating.

When did smallpox become extinct?

The WHO declared smallpox eradicated worldwide in 1980. The last known naturally occurring case occurred in 1977 in Somalia.

Smallpox was once a devastating disease responsible for millions of deaths, but vaccination has eradicated it worldwide.

Only people at risk of smallpox typically receive a smallpox vaccine. People may also receive the vaccination after exposure to smallpox, as it can reduce the symptoms. Smallpox vaccines may also provide protection from mpox.