In this article in the New England Journal of Medicine, Thomas Mack, an epidemiologist, questions the Bush Administration's policy for smallpox vaccination. He's got a good point: for every 1,000,000 people vaccinated, 3 or 4 people will die as a consequence of vaccination. Deaths from vaccine complications would outweigh any limited increase in protection, and since smallpox could be introduced anywhere -- the likelihood that the right healthcare workers would be where the outbreak occurs is small.
Dr Mack argues that a much smaller (~15,000) sulset of healthcare workers be vaccinated, and that we do a good job educating both physicians and the public about signs and symptoms of smallpox. This group would care for smallpox victims in separate healthcare facilities - limiting the risk of spreading the disease.