Current regulations and guidance define several pathways that facilitate expedited product development. These regulatory mechanisms allow for enhanced interaction between the sponsor and the FDA review team, flexible submission schedules, and, in some case, shortened review timelines. These pathways were created to better support development of new products where a defined unmet medical need exists. In response to the emergence of viruses that have caused regional and global public health emergencies, Ebola virus in 2014 and SARS-CoV-2 in 2020, respectively, the Agency conducted expedited reviews based on existing review mechanisms, but also utilized additional regulatory resources to facilitate the availability of safe and effective vaccines to help prevent disease from each of these viruses. This presentation will highlight the history of regulations related to vaccine development, review activities associated with vaccine development during an ongoing pandemic, and how lessons learned will be used to facilitate vaccine development and availability in the event of future public health emergencies.