DRAFT - Awaiting COP Review and Approval: The evolution of vaccine science over the past two centuries has been dramatic. Scientists advanced from injecting sometimes lethal bacteria into live farm animals to produce vaccines to creating novel vaccines in a lab. In addition, scientists discovered ways to produce stronger immune responses (adjuvants) and a way to use less vaccine per injection (the bifurcated needle). Safety and efficiency have become top priorities in vaccine development even with the pressures for mass production and speedy distribution.