^* Reporting is incomplete for this week. Numbers may change as more reports are received.

^†The New Vaccine Surveillance Network (NVSN) conducts surveillance in Monroe County NY, Hamilton County OH, and Davidson County TN.  The Emerging Infections Program (EIP) Influenza Project conducts surveillance in 60 counties associated with 12 metropolitan areas: San Francisco CA, Denver CO, New Haven CT, Atlanta GA, Baltimore MD, Minneapolis/St. Paul MN, Albuquerque NM, Las Cruces NM, Albany NY, Rochester NY, Portland OR, and Nashville TN.

^** Surveillance Regions: New England(Connecticut, Maine, Massachusetts, New Hampshire, Vermont, Rhode Island); Mid-Atlantic (New Jersey, New York City, Pennsylvania, Upstate New York); East North Central (Illinois, Indiana, Michigan, Ohio, Wisconsin); West North Central (Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South Dakota); South Atlantic (Delaware, Florida, Georgia, Maryland, North Carolina, South Carolina, Virginia, Washington, D.C., West Virginia); East South Central (Alabama, Kentucky, Mississippi, Tennessee); West South Central (Arkansas, Louisiana, Oklahoma, Texas); Mountain (Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, Wyoming); Pacific (Alaska, California, Hawaii, Oregon, Washington)

^***The national and regional percentage of patient visits for ILI is weighted on the basis of state population.

****The national and regional baselines are the mean percentage of visits for ILI during non-influenza weeks for the previous 3 seasons plus 2 standard deviations.  Non-influenza weeks are defined as weeks in which the percentage of specimens tested for influenza that is influenza positive is less than 10%.  It is not appropriate to use the national baseline for regional data.

^††Levels of activity are 1) no activity; 2) sporadic: isolated laboratory-confirmed influenza cases or laboratory-confirmed outbreak in one institution, with no increase in activity; 3) local: increased ILI in one region, or at least two institutional outbreaks (ILI or laboratory-confirmed influenza) in one region; virus activity no greater than sporadic in other regions; 4) regional: increased ILI activity or outbreaks (ILI or laboratory-confirmed influenza) in at least two but fewer than half of the regions in the state; and 5) widespread: increased ILI activity or outbreaks (ILI or laboratory-confirmed influenza) in at least half the regions in the state.