The number of patients with flu that doctors are seeing is also well below the seasonal baseline. So far, the states with the most cases of flu are New Jersey and Virginia, Cox said, adding that hard numbers are difficult to come by, so health officials are relying on anecdotal reports. "That is unusual for this time of year and is indicative of a relatively mild influenza season," she said.

But, the experts also said they're keeping a close watch on bacterial infections such as methicillin-resistant Staphylococcus aureus (MRSA). MRSA is resistant to certain antibiotics and can strike flu patients -- particularly hospitalized ones -- and is potentially fatal. Also, deaths from pneumonia associated with influenza are well below the epidemic level, Cox said. "The influenza activity we have seen in the United States has been relatively mild in comparison to last season," Jenda Cox, director of the U.S. The national baseline is about 2.4% -- the percent of patients with flu symptoms seen by doctors, Cox said. Centers for Disease Control and Prevention's Influenza Division, said during a teleconference.

The most com flu virus this year is influenza A -- primarily the.