The ACIP identified several contraindications to smallpox vaccination, and CDC included them in the screening process and in training and education materials. Prospective vaccinees would be excluded from vaccination for the following reasons: age (no one under 18 years old would be vaccinated in nonemergency situations), history of allergic reaction to vaccine or its components, breastfeeding, and moderate or acute illness. Prospective vaccinees would also be excluded if they or immediate household contacts had any of the following contraindications: pregnancy; disease, conditions, or treatments that cause immunosuppression or immune deficiency; and any acute, chronic, or exfoliative skin conditions, such as eczema and atopic dermatitis (CDC, 2003b). Furthermore, there are many people with compromised immune systems (because of HIV infection, immunosuppression for organ transplantation, or cancer therapy) for whom smallpox vaccine would hold a greater risk, and these conditions were included among the contraindications for smallpox vaccinations. Although there are many clinical data on reactions to smallpox vaccine, they predate contemporary immunosuppression. And very little information about fetal vaccinia and adverse events in inadvertently vaccinated pregnant women is available. After the vaccination of six civilians who later discovered that they were pregnant, ACIP established a pregnancy registry that would conduct follow-up of civilian and DoD pregnant women who were vaccinated (CDC, 2003g).

Concerns about program safety persisted. The present committee and the Association of State and Territorial Health Officials (ASTHO) recommended a pause between phases I and II to evaluate safety and ensure an adequate level of planning for expanded vaccination to a new population that required extensive communication and education for safety (for example, prevaccination screening and postvaccination site care). Phase III, intended to make the vaccine available to insistent members of the public, seemed even more problematic, in that it would pose public health threats, vast logistic challenges, and special and intensive communication requirements. Also, the final phase of the program would offer a potentially harmful vaccine in the context of an unknown risk, creating a philosophic conflict with health care and public health workers’ injunction to “do no harm” (AAP, 2003; Libbey, 2002).

In February 2004, the program’s safety profile reflected a small number of cases of inadvertent inoculation, indicating that vaccinees were probably effectively educated to prevent transmission. That and the fact that three of the four historically noted serious adverse events did not occur at all are also likely indicators of effective training and screening (see Table 3-1).

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