Influenza activity increased in the United States from Dec. 18 to Dec. 24 with eight states and the U.S. territory Guam reporting widespread activity, according to a weekly CDC influenza surveillance report. For the agency’s comprehensive flu update, both public health and clinical laboratories from across the country report on virologic surveillance on influenza specimens tested. Also, state and territorial epidemiologists report on the geographic spread of the virus.

So far, influenza A has accounted for 76.9% of the laboratory specimens tested and influenza B has accounted for 23.1%.

During week 51, the following influenza activity was reported:

  • Widespread influenza activity was reported by Guam, and eight states (California, New Hampshire, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, and Virginia).
  • Regional influenza activity was reported by the U.S. Virgin Islands, and 17 states (Alabama, Alaska, Colorado, Connecticut, Idaho, Indiana, Louisiana, Maryland, Massachusetts, Mississippi, Nebraska, New Jersey, North Dakota, Ohio, South Carolina, Utah, and Washington).
  • Local influenza activity was reported by the District of Columbia and 19 states (Arizona, Arkansas, Delaware, Florida, Hawaii, Illinois, Kentucky, Michigan, Minnesota, Missouri, Montana, Nevada, New Mexico, South Dakota, Tennessee, Texas, West Virginia, Wisconsin, and Wyoming).
  • Sporadic influenza activity was reported by five states (Iowa, Kansas, Maine, Rhode Island, and Vermont).
  • Puerto Rico and one state (Georgia) did not report

The percentage of patient visits to healthcare providers for ILI reported each week is weighted on the basis of state population. This percentage is compared each week with the national baseline of 2.2%.  Regional baselines for the 2016-2017 influenza season are:

Region 1 — 1.4%
Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont

Region 2 — 3.0%
New Jersey, New York, Puerto Rico, and the U.S. Virgin Islands

Region 3 — 2.2%
Delaware, District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia

Region 4 — 1.7%
Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and Tennessee

Region 5 — 1.9%
Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin

Region 6 — 4.1%
Arkansas, Louisiana, New Mexico, Oklahoma, and Texas

Region 7 — 1.8%
Iowa, Kansas, Missouri, and Nebraska

Region 8 — 1.4%
Colorado, Montana, North Dakota, South Dakota, Utah, and Wyoming

Region 9 — 2.5%
Arizona, California, Hawaii, and Nevada

Region 10— 1.1%
Alaska, Idaho, Oregon, and Washington

To read the CDC’s FluView report in its entirety, click here.