Immunizations - Smallpox

Smallpox

Vaccination against smallpox used to be routine in the US until 1972, and most older Americans bear the telltale small round smallpox vaccination scar on their upper arms. Immunity may last 10 years or longer. The last case of smallpox, a highly contagious and deadly disease caused by the variola virus, occurred in a laboratory worker in the UK in 1978.

However, the growing threat of bioterrorism has raised fears that smallpox could be used as a biological weapon, and in 2002 the US government issued plans for vaccinating every citizen against the disease in the event of an outbreak. The vaccination, however, carries some risks. Currently, then, vaccination continues to be recommended only for laboratory workers and scientists who work with the virus.

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If an outbreak occurs, guidelines from the CDC call for a so-called "ring vaccination" approach. This involves identifying anyone who comes into contact with an infected person and vaccinating them and their contacts with a single dose of vaccine. This includes people of all ages and even those at risk for vaccine complications. The vaccine may work even if given within the first few days of infection.

Who Should Be Vaccinated for Smallpox?

Those at increased risk of vaccine complications but who should still be immunized if they are actually exposed to an outbreak include the following:

Children younger than a year. About 42 infants out of a million will develop brain swelling that may result in retardation or death. A severe, body-wide rash may also occur, especially if children touch the vaccination site.
Pregnant women. There is a small risk of miscarriage or premature delivery, although smallpox itself in pregnant mothers has more serious implications.
People with skin conditions, particularly eczema. They may develop a widespread blistering rash called eczema vaccinatum, fatal in 1% to 6% of cases, and should not be vaccinated unless they''ve been exposed to the disease. They should also avoid others who have been vaccinated until those persons'' vaccination scabs heal and fall off. People with non-chronic skin conditions such as allergic rashes, severe burns, or chickenpox may be vaccinated once their skin condition clears up.
People with suppressed immunity due to HIV, organ transplants, high-dose steroids, cancer chemotherapy, or other conditions.
Should a severe rash or other complication develop, patients should notify their doctors immediately. Two investigational medications, vaccine immune globulin (derived from the blood of people who have been vaccinated against smallpox) and an antiviral drug called cidofovir (Vistide), may be administered intravenously in the hospital should serious complications arise.
In the event of an outbreak, current plans specify that vaccination against smallpox will remain voluntary, although unvaccinated people who are exposed to the disease may be quarantined for 18 days to help contain the spread of disease.