The Centers for Disease Control and Prevention reported the proportion of people seeing their healthcare provider for influenza-like illness increased again for the week ending Dec. 21, with eight regions reporting elevated levels of influenza-like illness. New York, New Jersey, Arizona, California, Hawaii and Nevada reported normal flu activity.
Colorado, Indiana, Kansas, North Carolina, Pennsylvania, South Carolina, Tennessee and Utah experienced moderate influenza-like illness activity, but six states experienced low influenza-like illness activity and 28 states experienced minimal influenza-like illness activity. The District of Columbia, New York City, Arkansas and Kentucky did not have sufficient data to calculate an activity level.
A total of four influenza-associated pediatric deaths were reported for the 2013-14 season.
Influenza A (H3N2), 2009 influenza A (H1N1), and influenza B viruses have been identified during this year's flu season. However, at this time, influenza A (H1N1) viruses predominated.
During the week ending Dec. 21, 1,610 of the 1,639 influenza-positive tests reported to CDC were influenza A viruses and 29 were influenza B viruses. Of the 937 influenza A viruses that were subtyped, 2.3 percent were H3 viruses and 97.7 percent were 2009 H1N1 viruses -- the same virus that predominated during the pandemic of 2009.
Alabama, Alaska, Kansas, Louisiana, Massachusetts, New York, Pennsylvania, Texas, Virginia, and Wyoming reported widespread geographic influenza activity -- more than half of the state's counties reporting elevated influenza-like illness.
Regional influenza activity was reported by Arkansas, Colorado, Connecticut, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kentucky, Maine, Michigan, Minnesota, Mississippi, Nebraska, Nevada, New Jersey, Oklahoma, Oregon, South Carolina, Tennessee, Utah and Washington.
Local influenza activity was reported by Arizona, California, Delaware, Maryland, Missouri, Montana, New Hampshire, New Mexico, North Dakota, Ohio, South Dakota and Wisconsin.
Sporadic influenza activity was reported by the District of Columbia, Hawaii, Rhode Island, Vermont and West Virginia.