The Philadelphia area is the historic center of vaccine science. Maurice Hilleman’s labs at Merck developed preventives for measles, mumps, meningitis, hepatitis, pneumonia, and flu, among others. Hilary Koprowski and colleagues at the Wistar Institute on the Penn campus developed vaccines against polio, rabies, and more. Scientists at Merck and GlaxoSmithKline labs in the western suburbs and start-ups in University City remain focused on new generations of vaccines.