Since the bombing of the World Trade Center in the United States on 9-11-01, concern has arisen regarding the use of smallpox virus for bioterrorism. In response to this potential threat, the Committee on Infectious Diseases of the American Academy of Pediatrics (AAP) (2002) has issued the following statement.
The AAP supports the Centers for Disease Control and Prevention (CDC) (2001) recommendation of the "ring vaccination strategy," also referred to as surveillance and containment. Using this approach, if smallpox were introduced in an act of terrorism, infected patients would be isolated. Primary contacts of infected individuals (friends, family, and co-workers), as well as secondary contacts (contacts of the contacts), would be identified and immunized by specially trained health professionals.
Contacts are individuals (1) who have had face-to-face, household contact or have been in close proximity to someone with smallpox lesions, (2) who have cared for such a person, or (3) who have been exposed to laboratory specimens or bedding from an infected person. The ring strategy is based on the knowledge that smallpox vaccination can prevent or ameliorate disease severity if given within 3 to 4 days of initial exposure and can decrease symptoms if given within one week of exposure.
Smallpox is a highly contagious disease caused by the DNA virus variola, a member of the genus Orthopoxvirus. The virus is spread by (1) droplets or aerosols from the oropharynx of infected individuals, (2) direct contact with infected lesions, or (3) contact with contaminated clothing or linen. Patients are contagious when the skin lesions form and until the scabs are shed. The last nonlaboratory case of smallpox occurred in Somalia in 1977.
Smallpox vaccine is a live-virus preparation that does not contain variola but a related virus called vaccinia. The vaccine is inoculated into the deltoid or lateral area of the lower leg using a bifurcated needle with a series of jabs that force the material beneath the epidermis (the technique is called scarification). Development of a pustular lesion indicates successful vaccination against smallpox. Presence of a residual scar, especially on the deltoid area, indicates previous vaccination (Grabenstein, 2002).
Routine smallpox vaccination was discontinued in the U.S. in 1972 and vaccine production was stopped in 1983. People immunized before 1972 are probably not fully immunized against the disease. Current supplies of smallpox vaccine in the U.S. are not sufficient for universal vaccination. Also, the vaccine can cause serious complications, including encephalitis, progressive vaccinia (a systemic infection from the vaccinia virus), eczema vaccinatum (a severe, sometimes fatal skin eruption), and death.
Nurses and other health care professionals need to be aware of current policies of the AAP and CDC regarding smallpox vaccination in order to answer questions from concerned parents and other citizens. Since most health professionals have never seen a case of smallpox, awareness of the systemic and skin manifestations is necessary for early identification of infected individuals. Smallpox is characterized by a 3- to 4-day prodromal period of chills, high fever, headache, backache, vomiting, and prostration. The temperature begins to subside as the eruptive stage starts on the third or fourth day. The eruptions progress from macular to papular to vesicular to pustular and finally to crusting during an 8- to 14-day period. The temperature rises again, and the constitutional symptoms intensify during the pustular stage. The rash has a characteristic peripheral or centrifugal distribution, with lesions at the same stage in any one regional area (Katz, 1998). In the event of a major outbreak, nurses will probably play a key role in vaccinating contacts who have been exposed to the virus.
November 17, 2002