Questions & Answers
Smallpox - Healthcare Workers
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Additional Concerns for Healthcare Workers

  1. In addition to the normal side effects already covered in earlier questions, is there more I need to know as a health-care provider?

    Yes. You should know a few of the more serious complications related to vaccination that can occur. Inadvertent inoculation is the most frequent complication of vaccinia vaccination. It accounts for about half of all complications of primary (first) vaccination and revaccination. Inadvertent inoculation usually results from auto-inoculation of vaccinia virus, transferred from the site of vaccination. The most common sites involved are places that itch: the face, eyelids, nose, mouth, genitalia, and rectum.

    Most auto-inoculation lesions heal without specific therapy, but vaccinia immunoglobulin (VIG) can help treat severe cases. If vaccinial keratitis develops, VIG is not recommended because of the risk of corneal scarring.

    Erythematous or urticarial rashes can occur about 10 days after primary (first) vaccination and can be confused with generalized vaccinia. In these circumstances, the vaccinee is usually afebrile and the rash resolves spontaneously within 2 to 4 days. Rarely, an allergic reaction to to the vaccination called erythema multiforme (i.e., Stevens-Johnson syndrome), may occur.

  2. What about moderate to severe adverse reactions?
    Moderate and severe complications of vaccinia vaccination include eczema vaccinatum, generalized vaccinia, progressive vaccinia, and postvaccinial encephalitis. These complications are rare, but occur more often among primary vaccinees than among revaccinees. These serious skin complications also are more frequent among infants than among older children and adults. A study of 10,000 Israeli military recruits aged 18 years or older, who were vaccinated during 1991 and 1996, reported no cases of progressive vaccinia or postvaccinial encephalitis. These results were similar to those reported in previous studies.

  3. What is eczema vaccinatum?
    Eczema vaccinatum is a localized or systemic dissemination of vaccinia virus among people who have atopic dermatitis or a history of atopic dermatitis or other exfoliative skin conditions (e.g., atopic dermatitis). Usually, this illness is mild and self-limited, but can be severe or fatal. The most serious cases among vaccine recipients occur among primary vaccinees, even among people who do not have active skin disease. Severe cases have been observed after recently vaccinated people had contact with people with atopic dermatitis or a history of atopic dermatitis.

  4. What is generalized vaccinia?
    Generalized vaccinia involves a vesicular rash of varying extent that can occur among people without underlying illnesses. The rash is generally self-limited and requires minor or no therapy, except among patients whose conditions might be "toxic" (as it refers to children) or who have serious underlying immunosuppressive illnesses (e.g., acquired immunodeficiency syndrome [AIDS]).

  5. What is progressive vaccinia?
    Progressive vaccinia (also called vaccinia necrosum or vaccinium gangrenosa) is a severe, potentially fatal illness. It appears as progressive necrosis reaching out from the vaccination site, often with metastatic lesions. It occurred almost exclusively among people with cellular immunodeficiency.

  6. What is postvaccinial encephalitis?

    The most serious complication is postvaccinial encephalitis. Two main forms were noted. The first affected children younger than 1 year old receiving their first (primary) smallpox vaccination, involving convulsions. These children may have residual paralysis after recovery.

    The second form affected children 2 years or older, adolescents, and adults receiving their first (primary) smallpox vaccination. These patients developed abrupt onset of fever, vomiting, headache, and malaise, followed by loss of consciousness, amnesia, confusion, convulsions, and coma. About 1 in 3 of these patients died.