Seasonal influenza vaccinations: specialized products for different target groups.

Traditionally, inactivated influenza vaccines have all been treated as virtually identical, at least in terms of recommendations for use. This has mostly been the case since their development over 60 years ago. The concept, still often quoted, that they are 70-90% protective against laboratory-confirmed clinical influenza comes from multiple studies carried out with different preparations in the US military; studies which ended in 1969 [1]. During this period, there were only gradual advances in improved potency and purity of the vaccines, so that it was appropriate to consider them as being comparable. However, we are currently witnessing a change, which started slowly, but is now accelerating, in which very different types of vaccine are becoming available. This has already begun in some parts of the world, but will soon be universal. The process is being accelerated by questions concerning the actual effectiveness of the current vaccines in specific risk groups. In this paper, we will take a look at the developments in the formulation of the vaccine to address the needs that have been identified. We will also consider different strategies for vaccine use which might be applied to traditional or future vaccines to improve population protection. 2010 Elsevier Ltd. All rights reserved.