ATLANTA — This winter's flu season has reached the epidemic stage, with a key indicator--a deaths-from-flu index--at its highest level in at least eight years, researchers with the Centers for Disease Control said Thursday.
Eighteen states are reporting "widespread" flu problems, and 17 more, including California, are reporting "regional" outbreaks, the CDC said.
To judge the severity of a flu season, CDC researchers track how many deaths are attributable to influenza or pneumonia.
Last week, 7.6% of 15,090 deaths reported to the CDC from 121 major cities were blamed on flu or pneumonia, and that "significantly exceeds" expected levels for the second straight week, said Dr. Walter Gunn, a CDC viral disease specialist.
"This qualifies in our definition as an epidemic," Gunn said, adding that the 7.6% mark is the worst weekly mark in records dating back to the winter of 1981-82. The CDC's epidemic definition is a ratio of 6.7% of deaths or above.
"This confirms our earlier concerns that this would be a worse-than-average year," Gunn said. CDC researchers feared a serious flu season when case reports started coming in last fall several weeks earlier than usual, he said.