In the Northeast, levels of flu have typically been lower than other regions, but several areas reported an uptick in swine flu, predominantly in the southern portion of the region. In Pennsylvania, Lancaster General Hospital had moderate to heavy levels, as did University of Pittsburgh Hospital. In New Jersey, Cooper Health in Camden reported moderate flu activity, though no ICU patients.
Many other medical centers in the Northeast remain relatively unscathed, with three Boston hospitals reporting light activity and several in the New York area, such as Beth Israel Medical Center, St. Luke's Roosevelt Hospital, St. Vincent Medical Center, and Staten Island University, also reporting light to very light flu levels.
Out West, the strong activity previously noted in some areas of California has seemingly migrated east to Denver and north to Oregon. Levels were moderate at the Oregon Health and Sciences University Hospital, and two hospitals in Denver, Colo. -- Porter Adventist and University of Colorado Denver Hospital -- now report heavy activity and swine flu patients in the ICU.
California, which has gotten a lot of attention for high levels of swine flu, was a prime example of how flu activity can vary greatly within a state and even within regions of a state. Of the seven California hospitals who responded to the ABC News query, two reported light flu activity, two heavy, and three moderate.
Dr. Larry Satkowiak, medical director of the emergency department at Children's Hospital Central California near Fresno, said that at his hospital, the virus has certainly added to the normal emergency department caseload.
"We're up about 25 percent from last October," he said. "Most of that is due to flu-related illnesses."
Roughly 300 miles south, Dr. Jake Jacoby, hospital director for emergency preparedness and response at the University of California at San Diego, said they "have not activated any surge steps at this point," he said.
"We are ready to deal with larger numbers of patients, but so far, we have not had to worry about that."
Even within the same city, levels can vary. At Georgetown University Hospital in Washington, D.C., levels are light, but across town at Providence Hospital, flu activity is at a "very heavy volume" according to Stephanie Herztog, director of public relations. At George Washington University's medical center, activity is somewhere in the middle.
Though these 20-odd "light" responders hint that there may be some areas less "widespread" than the CDC map would imply, there certainly are many hospitals nationwide struggling with heavy activity and widespread increases in ER volume.
Dr. Dennis Cunningham, medical director of the epidemiology department at Nationwide Children's Hospital, is currently seeing a bump in emergency department visits, but he notes that "when you talk to infectious disease experts, what they will always say is that the only thing that is predictable about influenza is that it's unpredictable."
"I've been doing this for 21 years, and there's just no way to predict what will happen with influenza," Satkowiak agreed. "We have no idea what the seasonal flu is going to do."