Global vaccine development.

Since the inception of the World Health Organization (WHO) Extended Programme on Immunization in 1974, vaccines have saved the lives of approximately 150 million children, and they continue to save 2-5 million lives each year, according to WHO estimates. The consensus around the benefit and funding of childhood vaccination in low- and middle-income countries has unraveled, and the hard-won gains of the past quarter century are at risk. At the same time, in some high-income countries, vaccine hesitancy-sometimes enabled by government policy pronouncements-has led to reductions in vaccination, resulting in outbreaks of measles in countries that had eliminated this disease. Despite these setbacks, advances in vaccine platform technologies, new immunogens, and new and expanding target populations have the potential to extend the direct and indirect effects of vaccination across the life course. In this Perspective, we discuss how each of these advances could shape the future vaccine landscape. We also highlight cross-cutting issues, including those related to equity, manufacturing, funding and vaccine hesitancy, which make successful implementation more complex.