The use of anthrax as a bioterrorism agent has stimulated concern and discussion
regarding the use of smallpox vaccine for healthcare providers, public health
officials responsible for investigating potential outbreaks and the general
public. In the April 25, 2002 edition of the New England Journal of Medicine,
several articles provide valuable information and opinions regarding this issue.
New information regarding the clinical responses to smallpox vaccine is
provided in 2 articles by Frey and colleagues [see box for links].
Photographs of adverse effects and tables of side effects
associated with smallpox vaccine in healthy, young adults are provided in Breman
and Henderson's article.
There were also articles by William Bicknell calling for voluntary smallpox
vaccination by the general public. Commentary from Drazen and Fauci call for a
national debate on this issue.
Most adverse events peek between 7 and 12 days after vaccination; the time
when the local lesions are at the peek at the vaccination site. Approximately
20% of vaccine recipients developed moderate or severe muscle aches or fatigue.
Pain at the vaccination site is considered to be moderate and approximately one third of the individuals also noted that the adverse events interfered with work
or recreational activities.
More severe side effects are reported in other studies going back to the time
when small pox vaccine was used routinely in the United States.
developed in 1-5 per thousand individuals vaccinated. When vaccine was
inadvertently administered to immunocompromised individuals who did not have
adequate cellular immunity,
progressive lesions developed that could be fatal unless the limb was
amputated. Also, 36.5% reported that they missed work, school or recreational
activities because of side effects associated with the vaccine.
infection at the vaccination site can be transmitted to other place on the body
by scratching or to immediate direct contacts of people who have received the
vaccine. Children or adults who have eczema can develop multiple severe lesions
throughout areas affected by eczema and some of these cases have been fatal. If
routine vaccination were performed with a catch-up program for all of the people
in the United States, experts have estimated that there would be 100-200 deaths
from complications from the vaccine.
The Advisory Committee on Immunization Practices (ACIP), which makes
recommendations for guidelines for the Centers for Disease Control and
Prevention, is currently debating what the specific recommendations should be
for smallpox vaccination. Draft guidelines have been developed and will be
presented at the June 2002 meeting.
The actual risk of the use of smallpox as a bioterrorism agent is unknown
although not zero. Active proponents of bioterrorism would succeed in causing
disruption and distrust of government and other public health organizations if
we caused far more harm from the routine use of this vaccine than might occur
from potential use of smallpox as a bioterrorism agent.
An alternative strategy has been proposed by the CDC. Smallpox vaccine is
effective for preventing serious disease when used up to four days after
exposure. If there were a recognized release of smallpox then exposed
individuals could be vaccinated up to several days after exposure. It is
virtually impossible to know when and where a bioterrorist might possibly
release smallpox. Undoubtedly, health care workers anywhere in the country could
be asked to see patient with possible smallpox. These workers need to be
adequately informed that the vaccine does work post-exposure and that the CDC
would release the vaccine for them and their colleagues. We believe that this is
the most sound strategy at this time and will cause the least harm. CDC may
choose to immunize additional ‘first responders’ and some large institutions
that care for complicated disorders may choose to immunize a small number of
people who would be potentially involved in the care of these patients. These
measures may be appropriate but we do not believe that it is indicated for the
general public to receive smallpox vaccine and we believe that the
recommendation should be against routine vaccination as the risks outweigh the