<p>The U.S. Army's Special Immunizations Program is an important component of an overall biosafety program for laboratory workers at risk of exposure to hazardous pathogens. The program provides immunizations to scientists, laboratory technicians and other support staff who work with certain hazardous pathogens and toxins. Although first established to serve military personnel, the program was expanded through a cost-sharing agreement in 2004 to include other government and civilian workers, reflecting the expansion in biodefense research in recent years. <em>Protecting the Frontline in Biodefense Research</em> examines issues related to the expansion of the Special Immunizations Program, considering the regulatory frameworks under which the vaccines are administered, how additional vaccines might be considered for inclusion in the Program, and factors that might influence the development and manufacturing of vaccines for the Special Immunizations Program.</p>