Fears of a bird flu outbreak led Americans to hoard the antiviral drug Tamiflu in 2005, with prescriptions spiking most sharply when media coverage rose, a study released on Tuesday said.

Filled prescriptions for Tamiflu rose nearly five-fold between September and October of 2004 and during the same period in 2005, according to the analysis by the U.S. Centers for Disease Control and Prevention (CDC) and pharmacy benefits manager Medco Health Solutions Inc.

Because there was little or no bird flu activity reported during these periods, the data suggest that patients were stockpiling the drug over fears of an epidemic, researchers note.

The study adds weight to anecdotal reports of patient hoarding one year ago, when governments around the world were scrambling to build up supplies of Roche Holding AG’s and Gilead Sciences Inc.‘s Tamiflu, one of only two drugs that can treat avian flu.

Roche suspended Tamiflu shipments to the United States last October because of fears people were hoarding it.

The H5N1 avian influenza is still primarily a bird disease, but has infected about 252 people and killed 148 people in 9 countries. The virus has not yet been found in North or South America.

The report found that Tamiflu prescriptions filled rose to about 134 claims per 100,000 enrollees in 2005, from about 27 prescriptions per 100,000 enrollees in 2004.

Researchers also analyzed media references to Tamiflu and found it tracked neatly with the boost in prescription rates.

“The correlation between the heightened U.S. media coverage around Tamiflu and the prescription activity for the drug between September and November in 2005 is uncanny,” said Robert Epstein, chief medical officer at Medco, which fills prescriptions for 55 million people in the U.S.

Last year, United States ordered 5 million treatment courses of Tamiflu and GlaxoSmithKline Plc’s Relenza, both antiviral drugs that can prevent and treat influenza if used very quickly.