The 2019-2020 U.S. Flu Season has come early to many states in the United States caused mostly by influenza B/Victoria viruses which is unusual for this time of year, the U.S. Centers for Disease Control reported.
The last time influenza B was the dominant flu strain in the U.S. was 27 years ago during the 1992-93 flu season.
Seasonal influenza activity in the United States has been elevated for the last four weeks and continues to increase, the CDC says.
Most Common Strain 2019-2020 Flu Season
Nationally, influenza B/Victoria viruses have been reported more frequently than other influenza viruses this season; followed by A(H1N1)pdm09 and A(H3N2) viruses, which are also circulating in significant numbers.
The predominant virus varies by region. The proportion of influenza B/Victoria viruses is increasing in some regions, while the proportion of A(H3N2) viruses is decreasing overall.
CDC Early Flu Season Map 2019
During the week ending November 30, 2019, Puerto Rico and 12 states (Alabama, Georgia, Louisiana, Minnesota, Mississippi, Nebraska, Nevada, New Mexico, South Carolina, Tennessee, Texas, and Washington) experienced “high” influenza activity
New York City along with 14 states (Arizona, Arkansas, Colorado, Connecticut, Florida, Hawaii, Kentucky, Maryland, Missouri, New Jersey, North Dakota, Oklahoma, Utah, and Virginia) experienced moderate activity.
The District of Columbia and eight states (California, Illinois, Massachusetts, New York, North Carolina, Oregon, Pennsylvania, and Wisconsin) experienced low activity (Alaska, North Dakota and Utah).
Alaska, Delaware, Idaho, Indiana, Iowa, Kansas, Maine, Michigan, Montana, New Hampshire, Ohio, Rhode Island, South Dakota, Vermont, West Virginia, and Wyoming experienced minimal activity.
2019 Florida Flu Season Map
Flu activity increased and remained above levels observed at this time in previous seasons in the Sunshine State, the Florida Department of Health reported.
Influenza & influenza-like illness (ILI) activity remained particularly elevated in Florida children for this time in the season. About one in 10 visits among children at participating emergency department and urgent care centers were for ILI.
So far this season, influenza B Victoria remains the most common flu strain in Florida this year.
In Florida, influenza A 2009 (H1N1) or influenza A (H3) viruses were predominant during the past 10 influenza seasons, but some level of influenza B circulation is typically observed throughout each season.