Infectious disease experts oppose smallpox shots for public

Dec 11, 2002 (CIDRAP News) – The 7,000-member Infectious Diseases Society of America (IDSA) has urged President Bush not to make smallpox vaccine available to the public for now, on grounds that serious reactions to it could undermine public confidence in the shots and in other immunizations as well.

"Due to the known risks associated with smallpox vaccinations, at the present time we urge that the national plan not include vaccination of the general public," IDSA President W. Michael Scheld, MD, told Bush in a Dec 3 letter.

The IDSA supports vaccinating healthcare workers who would respond to a smallpox outbreak and preparing the public health infrastructure for a mass immunization program in case that becomes necessary, Scheld stated. But the society believes that "the very low risk of a smallpox transmission event does not justify a pre-emptive mass vaccination of United States citizens at the present time, even on a voluntary basis."

Many infectious disease physicians feel that mass immunization would create a needless risk of serious adverse reactions in vaccinees and transmission of the vaccinia virus to their contacts, Scheld wrote. He continued, "These adverse events will be readily measurable, and across the general population could well serve to undermine confidence in smallpox vaccination and willingness to be vaccinated should the need arise. This could prove disastrous from both a national defense and a public health viewpoint if mass vaccination were to be undertaken in response to a terrorist release of smallpox. In addition, concerns about adverse reactions from the smallpox vaccine could serve to undermine the public's confidence in other immunizations (e.g., influenza, measles/mumps/rubella), which are important in protecting public health."

Potential adverse reactions to smallpox vaccination include accidental inoculation of other body sites, generalized vaccinia, eczema vaccinatum, progressive vaccinia, postvaccinial encephalitis, and death. In past smallpox immunization campaigns, the shot caused life-threatening reactions in about 15 cases per million vaccinations and was fatal in about one case per million.

The Bush administration has been weighing decisions about smallpox vaccination for months. In October, the federal Advisory Committee on Immunization Practices (ACIP) recommended vaccination of hospital staff members who would care for smallpox patients in the event of an outbreak. Meanwhile, the states, under requirements tied to federal grants for bioterrorism preparedness, have been preparing plans for preemptive vaccination of healthcare workers and postoutbreak vaccination of the public.

The IDSA letter to Bush reiterated a position the society took in a letter to the ACIP last June, when the committee was reviewing its smallpox vaccination recommendations. At that time, the IDSA said an immunization program for Americans aged 1 to 65, excluding high-risk people and their contacts, could cause 4,600 serious adverse events and 285 deaths.

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