Charles Krupa, Associated Press
In a Jan. 9, 2013 file photo, four-year-old Gabriella Diaz sits as registered nurse Charlene Luxcin, right, administers a flu shot at the Whittier Street Health Center in Boston, Mass. In the midst of a worrisome flu season, health officials are pushing doctors to prescribe antiviral medicines.

NEW YORK — In the midst of a worrisome flu season, health officials are pushing doctors to prescribe antiviral medicines.

The Centers for Disease Control and Prevention on Friday sent a new alert to doctors, advising prompt use of Tamiflu and other antivirals for hospitalized flu patients and those at higher risk for complications like pneumonia.

CDC research suggests doctors prescribe antivirals to one in five high-risk flu patients. CDC officials say the number should be higher.

One reason is physician uncertainty: CDC says the drugs reduce hospitalizations and complications, but some researchers have said there's not good evidence that's true.

CDC officials say the flu season may be about half over, though it's hard to be sure. Flu is now widespread in 46 states.

Online:

CDC flu update: http://www.cdc.gov/flu/weekly/