Influenza and pneumococcal vaccination: how far we have come and how to go farther.

The recent outbreak of avian influenza in Asia is a timely reminder of the ever present possibility of a human influenza pandemic in the near future. Work continues to develop vaccines effective against emergent influenza strains, but another component of effective prevention and infection control programs is the ability to administer vaccine in a timely and efficient manner. Even in the absence of a pandemic, influenza-associated respiratory and circulatory illness results in more than 200,000 hospitalizations and 36,000 deaths each year in the United States, according to recent estimates. These numbers suggest that the routine administration of influenza vaccine to targeted populations remains a major challenge.