According to the CDC's map of flu activity, 46 states are currently reporting widespread H1N1 flu cases. Since almost all states have by now reported outbreaks, this map, which only a month ago was dappled with the different colors of flu levels, is now almost uniformly brown.
The CDC notes on its site that the map only shows geographical trends and "does not measure the severity of influenza activity." But with the CDC reporting little variance between states, let alone within each state, it is easy to conclude that the amount of swine flu activity is the same across the country.
A check of 60 hospitals by ABC News suggests a very different picture. The collection of reports from these hospitals, though not a scientific sample, suggested that not only does the extent and severity of the illness vary from region to region, but in some cases it varies even among hospitals in the same state.
In order to get a better idea of how flu activity varies across the nation, we asked hospitals to rate their level of flu activity in their emergency department and report the number of H1N1 patients in their intensive care unit (ICU) -- a sign that at least some cases were severe enough to warrant extraordinary treatment measures.
At least 10 out of the 60 hospitals reported heavy activity of H1N1 in their emergency departments, but nearly twice as many said flu levels were "moderate" and the largest proportion, 21 hospitals, said that the situation was "light" in their ER and reported few, if any, patients in the ICU due to swine flu-related problems.
There is no doubt that there are areas where flu activity is high. The Midwest remained the heaviest area of activity, and other "heavy" hospitals were spread out across the country.
In Columbus, Ohio, both the Nationwide Children's Hospital and Ohio State University Medical Center, have several patients who are currently on lung and heart support machines. They both reported heavy levels.
Richard Davis, associate executive director of Ohio State University Hospital and the Ross Heart Hospital, also in Columbus, said that out of a total of 38 medical ICU beds, there were only three that were unfilled.
"That's a pretty fine margin, frankly," Davis said. "We, like others, have a very thin excess when it comes down to ICU capacity."
In the South, there were signs that the strong activity was declining in some areas but not others. In the past month, such areas as Austin, Texas, attracted national attention when Dell's Children's Medical Center in Austin set up a tent outside the emergency department to accommodate all the people arriving with flu-like symptoms. But today several hospitals in Texas including the Harris County Hospital District reported light activity.
Though the southern states were among the first to receive the CDC's brown label, indicating "widespread" activity, flu levels seem to be easing up a bit with Emory University, in Atlanta, Ga., and Baptist Hospital Northeast in La Grange, Ky., reporting light activity.
However, there are still areas of the south where flu activity seems strong. In Florida, flu levels were still reported as heavy.
A spokesperson for the Hillsborough County emergency department in Tampa, Fla., said influenza-like illnesses are "well above what we normally see at this time of year," and Florida Hospital in Orlando, reported 4 patients in the ICU for H1N1-related complications.