MedImmune ( MEDI) said Monday that the Food and Drug Administration has cleared a new, easier-to-store version of its FluMist nasal-spray flu vaccine.

The updated product will be available for the 2007-2008 flu season and requires only storage in a standard refrigerator instead of needing to be frozen.

Storage was one reason why FluMist has been a financial disappointment after its introduction during the 2003-2004 season. A high price, reluctance of insurers to pay for it and the fact that it isn't approved for the very old or very young have caused FluMist to remain a minor player in the flu vaccine market.

"We are confident that the approval of our refrigerated formulation for FluMist will encourage more health care providers to offer FluMist to their customers and patients," said Dr. Frank Malinoski, senior vice president for medical and scientific affairs, in a prepared statement. The new formulation was known in clinical trials as CAIV-T, which stands for cold adapted influenza vaccine-trivalent.

"We recognize that the frozen storage presented difficulties for some physician practices, as well as for providers who administer vaccine in places like schools, pharmacies and grocery stores," Malinoski said.

MedImmune hopes to secure FDA approval for FluMist in younger children. Right now, it is approved for healthy people between the ages of 5 and 49.

The company has been testing FluMist in clinical trials covering people as old as 98 and as young as six weeks.