Continuing mortality and morbidity from smallpox vaccination.

Three cases of cross-infection after smallpox vaccination are described, in two of which the outcome was fatal. Probably all occurred because simple precautions were not observed at the time of vaccination--for example, exclusion of contraindications and warnings about risks. If those countries still requiring evidence of vaccination for entry were to abolish this rule, however, the risk of cross-infection could be eliminated. Vaccinating a person with contraindications is justified only when exposure to smallpox has occurred.