Smallpox is a contagious viral illness caused by the variola virus. The virus can spread from an infected person through the air when there is fairly prolonged (1-3 hours) direct contact. It can also spread via body fluids, either by direct contact with fluids from an infected person or by touching objects that have been contaminated by infected body fluids. The last documented case of smallpox disease occurred in 1977. However, smallpox is still considered a possible biological threat.
An infected person usually begins to experience symptoms 12 to 14 days after exposure. Smallpox disease results in a fever and viral-like symptoms, followed by a rash that progresses from papules to pustules. Eventually the pustules form scabs and the scabs fall off. People with smallpox can spread the virus to others beginning when their fever is 101°F until all their scabs fall off.
There is no proven cure for smallpox. Historically, death has occurred in about 30% of cases. Giving smallpox vaccine soon after exposure to the virus can help to reduce the effects of smallpox disease. Vaccine given within 3 days after exposure can help prevent death. Vaccine given within 7 days after exposure can result in a less severe (modified-type) smallpox illness.
There is only one smallpox vaccine available in the United States. It is a live, attenuated vaccine made from vaccinia virus. Vaccinia virus is closely related to variola virus, which is the virus that causes smallpox. Immunity against vaccinia virus also provides protection against variola virus. It is administered using a bifurcated needle that is jabbed into the surface of the skin.
To reduce the chance of spreading the vaccine virus to other body parts or other people, please follow these recommendations:
You should follow the same instructions on "How should I care for the vaccination site?" and read the following:
Even patients vaccinated in the past may be at increased risk due to current immunodeficiency. If contact with unvaccinated patients is essential and unavoidable, healthcare workers can continue to have contact with patients, including those with immune deficiencies, as long as the vaccination site is well-covered and thorough hand-hygiene is maintained. In this setting, a more occlusive dressing might be appropriate. Semi-permeable polyurethane dressings (e.g., Opsite®, Tegaderm®) are effective barriers to vaccinia and recombinant vaccinia viruses.
However, exudate may accumulate beneath the dressing, and care must be taken to prevent viral contamination when the dressing is removed. In addition, accumulation of fluid beneath the dressing may increase the maceration of the vaccination site. To prevent accumulation of exudates, cover the vaccination site with dry gauze, and then apply the dressing over the gauze. The dressing should also be changed daily or every few days (according to type of bandaging and amount of exudate), such as at the start or end of a duty shift.