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Indiana State Department of Health
Facts About Smallpox
What is smallpox?
- Smallpox is a serious disease caused by the variola virus that was announced as eradicated, or wiped out, by the World Health Organization in 1980.
- However, smallpox remains a serious threat due to the possibility that some of the remaining stock, if in the wrong hands, could be grown and adapted for bioterrorism purposes.
- Smallpox has a fatality rate of 30 percent or more.
How is smallpox spread?
- Smallpox spreads directly from person to person, primarily from the mouth and throat droplets or aerosols from the infected person.
- In addition, contaminated clothes or linens can also spread the virus.
- Transmission is highest during the onset of rash through the 7th to 10th days of the rash.
- As the scabs form, the infectivity of smallpox declines.
- Because of changes in temperature and humidity, there is more occurrence of smallpox in the winter and early spring.
- There are no known animal or insect reservoirs or carriers to transmit smallpox.
What are the symptoms of smallpox?
- After the incubation period, 10-12 days on average, high fever, malaise, headache, and backache develop.
- Abdominal pain and delirium or disorientation sometimes occur.
- Small, colored, bumpy rash begins on the mouth, pharynx, face, and forearms, spreading to the trunk and legs.
- Within 1-2 days, the rash becomes blisters, and then round and deeply set pimples with pus form in the skin.
- Within 8-9 days, the pimples with pus become crusted.
- Scabs separate, leaving pigment-free skin, and eventually pitted scars form.
How can smallpox be treated?
- Treatment of smallpox is limited to supportive therapy and antibiotics for secondary bacterial infections.
- There are no antivirals, treatments to kill or suppress the virus that have proven to be effective.
Is there a smallpox vaccine?
- There is a vaccination for smallpox. However, routine vaccination stopped in the United States in 1972, and production of the vaccine had ceased by 1980, due to the eradication of smallpox.
- Those who received the vaccinations before 1972 do not have lifelong immunity because it declines within a 5-10 year period after the vaccination.
- A limited supply of vaccine still exists in the United States under Center for Disease Control and Prevention authority.
- Vaccines administered within 3 days of the first exposure have shown to offer some protection against getting infection and significant protection from mortality.
What are the precautions to take against smallpox?
- Patients should be isolated or confined in rooms with high air filtration.
- Standard precautions (gloves, mask, and gown) should be worn.
- All laundry and waste should be sterilized with steam under pressure before being laundered or destroyed.
- Standard hospital disinfectants should be used for surface decontamination.