A team of researchers has now engineered a virus nanoparticle vaccine against Bacillus anthracis and Yersinia pestis, tier 1 agents that pose serious threats to national security of the United States. B. anthracis and Y. pestis are the pathogens that cause anthrax and plague, respectively. Using bacteriophage T4, the scientists developed the vaccine by incorporating key antigens of both B. anthracis and Y. pestis into one formulation. Two doses of this vaccine provided complete protection against both inhalational anthrax and pneumonic plague in animal models.