Reinstating smallpox vaccination programs to protect the public against bioterrorism is currently a topic of considerable debate. Some countries additionally recommend the practice for laboratory workers who encounter Vaccinia, the cowpox virus that is the basis of the vaccine and which is used as a cassette in other vaccines. Acquiring active infection by working with Vaccinia has been assumed to be unlikely, but in the March 2003
Mempel et al. recognized vesicles that gradually turned into raised, dark nodules as similar to those that develop during cowpox infection. The patient had no contact with farm animals, but had worked with lab strains of Vaccinia containing human genes — in ...
