Lessons learned from smallpox vaccination of U.S. Navy forces before Operation Iraqi Freedom.

Our objectives were to document and to analyze the U.S. Navy's smallpox vaccination program before Operation Iraqi Freedom, discerning lessons for future mass vaccination programs. This research scrutinized the challenges inherent in vaccinating approximately 40,000 personnel at diverse locations within a few weeks. We interviewed and observed participants at multiple locations throughout the vaccination process, while also collecting documentation. Subsequently, we analyzed how the Navy addressed the challenges of mass vaccination on a compressed timeline. We found that the population was vaccinated with no significant logistical challenges, few medical complications, almost no refusals, and minimal operational impact. Our analysis led us to conclude that two primary factors contributed to the vaccination program's success; both of these can be replicated in future mass vaccination programs. The first factor was a strong educational program, which repeated consistent messages via multiple communications channels. The second factor was vocal, demonstrative, high-level support for vaccination.