The importance of vaccine stockpiling to respond to epidemics and remediate global supply shortages affecting immunization: strategic challenges and risks identified by manufacturers.

While stockpiling vaccines adds another layer of complexity to vaccine manufacturing, it constitutes a crucial component of comprehensive disease preparedness and control strategies in public health management. Stockpiling provides the ability to immediately respond to epidemics, disease outbreaks, vaccine shortages or stock-outs at local, regional or global levels. Some stockpiles are static, not shipped until an emergency occurs; other stockpiles are rotating with vaccines used in on-going routine immunization programmes. Programmatic use indicates which vaccines to stockpile, the nature of the stockpile and the amount of vaccine to be held at any time. For immediate shipment, fully released product must be stockpiled with the challenge of monitoring remaining shelf-life requirements and the potential risk of expiry. Existing stockpiles are managed and financed globally under the purview of international organizations in the global immunization community, except for buffer stocks held by manufacturers for short periods. The added challenges to manufacturers of stockpiling vaccines, including storage, human resources and other related costs including vaccine destruction when no longer useable, needs to be recognized. This is all the more so with the likelihood of vaccine stockpiling becoming more prominent with changing disease patterns due to climate change and population movements, as well as the significant investment in the research and development of new epidemic prevention vaccines. While vaccine stockpiles managed and financed globally provide rapid response to country requests, more attention is needed in the future to ways that vaccine stockpiling can be brought under the direct purview of individual countries or regional groupings.