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What is smallpox?

Smallpox is a disease caused by variola virus which was feared for centuries because it caused serious illness, disfiguration, and often death. After a successful public health vaccination campaign, it was declared to be eradicated from the world in 1980. Although naturally occurring disease has been eliminated, serious concerns about smallpox are rising again because of its possible use as a bioterrorist weapon

How is smallpox spread?

Smallpox is spread from one person to another by infected respiratory droplets.  Smallpox patients are highly contagious during the first week of illness, since that is the time when the largest amount of virus is present in the throat.  However, some risk of transmission lasts until all scabs have fallen off.  Contaminated clothing and bed linens can also spread the virus.

What are the symptoms of smallpox?

Smallpox has an average incubation period of 12 to 14 days after exposure.  Initially, patients experience high fever, fatigue, headache and backache.  Severe abdominal pain and delirium are sometimes present.  A rash appears within two or three days, first in the mouth and throat, spreading to the face and forearms, and then to the trunk and legs.  Within five to seven days, the rash develops into pus-filled lesions which later crust into scabs.  

How is smallpox treated?


There is no proven effective treatment for smallpox, but research to evaluate new antiviral medications is ongoing.  Patients with smallpox can benefit from supportive treatment such as intravenous fluids and medicine to control fever or pain, as well as antibiotics for any secondary bacterial infections that occur.  In the 1970s, smallpox was fatal in 30 percent of cases.

Can vaccine protect a person even after they have been exposed to smallpox?

Vaccine can lessen the severity of or even prevent illness in people exposed to smallpox if given within three to four days of exposure.  The United States has an emergency supply of smallpox vaccine.

I was vaccinated against smallpox as a child.  Will that vaccination still protect me?

Routine vaccination against smallpox ended in 1972.  The level of immunity, if any, among persons who were vaccinated before 1972 is uncertain; therefore, those persons are assumed to be susceptible.

Can I get a smallpox vaccination?


Under current circumstances, with no confirmed smallpox and the risk of an attack assessed as low, vaccination of the general population is not recommended because the potential benefits of vaccination do not outweigh the risks of vaccine complications.  Following a confirmed outbreak of smallpox within the U.S., rapid voluntary vaccination of a large population may be conducted as part of an overall national vaccination strategy.  The decision to do mass vaccination will be dependent upon an assessment of the magnitude of the attack, the potential duration of the attack, and the mode of the attack.

How much smallpox vaccine is available?

Currently, we have a stockpile of 85 million doses of vaccine. A recent National Institute of Health study found that the existing supply can be increased to make enough for the entire population in the event of an outbreak. A contract has been issued to produce an additional 210 million doses this year. It is anticipated that a total of 286 million doses of smallpox vaccine will be available at the end of this year.  The CDC's Strategic National Stockpile has developed protocols to allow for the rapid, simultaneous delivery of smallpox vaccine to every state and US territory within 12-24 hours. State and local governments are developing response plans to provide for the rapid distribution of vaccine on a large-scale basis.

Who is at highest risk for side effects from the vaccine?

People most likely to have side effects are people who have, or even once had, skin conditions, (especially eczema or atopic dermatitis) and people with weakened immune systems, such as those who have received a transplant, are HIV positive, or are receiving treatment for cancer. Anyone who falls within these categories, or lives with someone who falls into one of these categories, should NOT get the smallpox vaccine unless they are exposed to the disease. Pregnant women should not get the vaccine because of the risk it poses to the fetus. Anyone who is allergic to the vaccine or any of its components should not get the vaccine. Vaccination of persons less than 18 years of age is not recommended in non-emergency circumstances.

Where can I call for more information?

Contact the Tennessee Department of Health at (615) 741-7247.

Healthcare providers, laboratories, and public health professionals can find more information about this disease and a variety of others at the Tennessee Department of Health Reportable Diseases and Events home page