Many health departments and doctors' offices are reporting delayed or none vaccine shipments. This is raising panic among highest-risk patients who are turning on to other sources of vaccine shots.

Federal health officials insist there will be plenty of vaccine to go around in a few more weeks but the manufacturers are not reporting final dates. In the meanwhile, mass purchasers are opening flu-shot clinics at pharmacies, grocery stores and other retailers.

It is expected that the nation's ultimate supply reach the number of 91 million doses but the problem is shipments too late in the season may be wasted, as patients seek shots elsewhere or give up.

There aren't simple solutions as flu shots take months to brew, and must be made fresh each winter to match newly circulating influenza strains. The government is finding ways to speed the process and increase the number of vaccine manufacturers.