By MATT LEVIN and ROBERT J. KENNEDY-DICKMANAssociated PressU.
S. health officials said Tuesday they have ordered doctors in at least 20 states to prescribe flu shots to prevent the flu.
The Centers for Disease Control and Prevention said it will be more effective for health care workers to administer the shots to the sickest patients and those with the highest risk of getting sick.
Health officials have ordered that doctors prescribe the shots for the first time in about three weeks, in the wake of an outbreak of H1N1 influenza in Ohio.
About 300,000 people were hospitalized in the U.S., most in Ohio, Pennsylvania and West Virginia.
Officials said that for the vast majority of the cases, the virus spread quickly through the respiratory system, which is where the most people are exposed.
In addition to Ohio, the flu has been traced to two states in Minnesota and New Mexico.