INFLUENZA VACCINES

The shortage of influenza virus vaccine in the United States in late 2004 illustrates the major challenges that the United States faces in consistently providing reliable supplies of vaccines. The lack of a reliable market and a return on investment left only two manufacturers of inactivated influenza vaccine in the United States. The loss of vaccine supply from one of these manufacturers created a severe shortage of vaccine, with the result that many individuals considered to be at increased risk of complications from influenza infection could not obtain vaccination. (Although the recent introduction of an attenuated live influenza virus vaccine administered intranasally has added a third supplier in the United States, this vaccine has been approved for use only in otherwise healthy individuals between the ages of five and fifty years. However, these age groups are not those at highest risk of complications from influenza virus infections.)

Millions of unused influenza vaccine doses are discarded over the years due to the vagaries of influenza epidemic severity and vaccine usage, as well as the complexities of vaccine production and the fact that the new vaccines produced each year must contain the most contemporary variants of the three strains of influenza expected to cause illness in the next influenza season. Although vaccine liability concerns add additional uncertainty for manufacturers of vaccines, the National Vaccine Injury Compensation Program (VICP) has greatly reduced the liability risks for these manufacturers.