Administration of a tissue-cultured smallpox vaccine showed signs of an effective vaccine response with no serious adverse events, according to a study in the March 11 issue of JAMA, the Journal of the American Medical Association.
"The threat of smallpox bioterrorism has prompted reconsideration of the need for smallpox vaccination. Serious adverse events associated with first-generation vaccines such as the New York City Board of Health (Dryvax), Lister, and Ikeda strains have raised obstacles to vaccination campaigns in the United States," the authors write. They add that certain second-generation vaccines are also often accompanied by a high frequency of adverse events. "Developing a vaccine that is safer than first-generation vaccines yet highly immunogenic [producing immunity or an immune response] is crucial to constructing a prevention plan in the event of bioterrorist attack."
Tomoya Saito, M.D., Ph.D., of Keio University, Tokyo, and colleagues examined the clinical and immunological responses to the LC16m8 vaccine in adults who had been previously vaccinated (n = 1,692) and in those who had not (n = 1,529). LC16m8 is a live, attenuated (reduced in strength), tissue-cultured third-generation vaccine that was administered to more than 100,000 infants in Japan between 1973 and the beginning of 1976. The adults in this study, who are in the Japan Self-Defense Forces, received the LC16m8 vaccine between 2002 and 2005. Vaccinees were examined 10 to 14 days after vaccination to determine if they had developed a major skin reaction ("take"; a measure of immune response). The researchers monitored vaccinees for adverse events for 30 days after the vaccination.