David B Weiner is in the Department of Pathology and Laboratory Medicine, University of Pennsylvania, 505 Stellar Chance Building, 422 Curie Boulevard, Philadelphia, Pennsylvania 19104, USA. dbweiner@mail.med.upenn.edu
Since the eradication of natural smallpox infection, research efforts have waned and the vaccine is now outdated. Two studies revitalize efforts to create a new smallpox vaccine. One study moves vaccine production from animals into tissue culture; the other examines duration of immunity in already vaccinated individuals (pages 1125−1139 and 1131−1137).
