U.S. health officials are seeing a surprisingly high number of cases of ordinary, seasonal flu at a time when the flu season typically peters out.
About half of people recently testing positive for the flu have the new swine flu virus, Dr. Daniel Jernigan of the Centers for Disease Control and Prevention in Atlanta said Friday.
"The H1N1 virus is not going away," Jernigan said. The virus "appears to be expanding throughout the United States" and poses "an ongoing public health threat," he said.
Swine flu continues to affect more younger people — those ages 5 to 24 — and CDC is still seeing relatively few cases in older people
In the United States, there are now more than 4,700 probable and confirmed cases of swine flu, and 173 hospitalizations and four deaths, Jernigan said. The tally doesn't include a fifth death that Texas officials said Friday was due to swine flu.