The expanding vaccine development pipeline, 1995-2008.

Successful launches of recently licensed vaccines contrast with pharmaceutical industry concerns about unfavorable market conditions, making the status and future of vaccine development uncertain. We assessed trends in private-sector vaccine research and development for the period 1995-2008, using a global pharmaceutical database to identify prophylactic vaccines in preclinical, Phase I, Phase II, or Phase III stages of development. We counted companies that research and/or manufacture vaccines ("vaccine originators") and their vaccine products in each year. The global number of vaccine originators doubled (to 136), as did the number of prophylactic vaccine products in development (to 354); the majority of this growth was in preclinical and early phase clinical research. Because rapid growth in earlier research phases has not yet led to growth in Phase III, it is not yet clear whether recent industry expansion will translate to an increase in the number of available vaccines in the near future.