Smallpox is an acute, contagious rash illness caused by the variola virus. Patients have fever and a distinctive, progressive skin rash. After exposure, it may take between seven and 17 days (average 12 to 14) for symptoms of smallpox to appear. During this time, the infected person feels fine and is not contagious.
The symptoms of smallpox begin with high fever, head and body aches and sometimes vomiting. A rash follows that spreads and progresses to raised bumps that crust, scab and fall off after about three weeks, leaving a pitted scar. A person with smallpox becomes infectious, or contagious, once a rash appears and is usually very sick and not able to move around in the community. After the appearance of a rash, the infected person is contagious until the last smallpox scab falls off.
There is no proven treatment for smallpox, but research to evaluate new antiviral agents is ongoing.
The smallpox vaccine is the best protection you can get if you are exposed to the smallpox virus. Smallpox vaccine does not contain any smallpox virus. Instead, it is made from a virus called vaccinia, which is another "pox"-type virus related to smallpox. Most people who are vaccinated experience only mild reactions that can include a sore arm, fever, and body aches. However, people with eczema, immune system disorders, pregnant women and children under one year of age have a higher risk of complications from the vaccine.
At the moment, the smallpox vaccine is not available to members of the general public. However, there is enough smallpox vaccine available in national stockpiles to vaccinate everyone who would need it in the event of an emergency. A detailed nationwide smallpox response plan to vaccinate people quickly and to contain smallpox outbreak is under development.