(CNN) At least 1,300 people have died from the flu so far this season, according to a preliminary estimate released Friday by the US Centers for Disease Control and Prevention.

There have been at least 2.6 million flu illnesses and 23,000 flu-related hospitalizations, according to the analysis.

So far this season, the CDC has received reports of 10 children who have died from the flu, four more than the week before.

Experts have warned that flu is hitting the United States early this year, and there are concerns that this early season could mean a particularly severe season overall.

Flu spread significantly in all states except Alaska as of the week ending December 7. Both the eastern and western United States are being hit hard, with widespread flu activity in 23 states: Alabama, Arizona, California, Connecticut, Georgia, Idaho, Indiana, Kentucky, Louisiana, Maryland, Massachusetts, Nebraska, Nevada, New Mexico, New York, North Carolina, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Virginia and Washington.

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