Jan. 14, 2011 - Don't put off your flu shot any longer: The winter flu season has arrived.
While only four states have high levels of flu activity, the seasonal illness is widespread across 11 states. And there's evidence of outbreaks in several U.S. cities.
Sadly, four children died of flu in the first week of January, the latest week for which CDC data is available. So far, the 2010-2011 flu season has claimed the lives of eight children. There were 282 U.S. pediatric deaths during last year's flu pandemic, 133 in the 2008-2009 season, and 88 in the 2007-2008 season.
Hospitals in 122 U.S. cities report that deaths from "pneumonia and influenza" -- a statistic that reflects flu activity -- are at the epidemic level. They've been on the upswing since just before Christmas.
While the CDC data show that flu definitely has arrived, they do not predict where, when, or even whether the disease will flare up or die down. In states with high flu activity, flu may be limited to one or two large cities. And in states with widespread flu activity, there may be few if any hot spots.
Unlike Europe, where high flu activity is mainly due to the 2009 H1N1 flu bug, the U.S. flu epidemic is mixed. Most of the flu is type A, with the old H3N2 flu bug predominant but with a good bit of 2009 H1N1 activity. About one in four cases are type B flu.
Happily, nearly all the flu cases have been caused by flu viruses included in this year's three-in-one seasonal flu vaccine.
This year, the CDC is tracking a new flu statistic: the percentage of hospitalized flu patients who have certain underlying conditions. So far this year, among people hospitalized for flu: