Flu season is intensifying in the U.S. with more than 6 million cases confirmed so far, the Centers for Disease Control and Prevention (CDC) reported on Monday.

The federal health agency said in a weekly update it has already recorded more than 53,000 hospitalizations and 2,900 deaths from the flu this season, as of the week ending Nov. 19.

Twelve children have died from the flu so far, the CDC said, and the cumulative hospitalization rate is the highest it’s been at this point in the flu season since the 2010-2011 one.

The CDC recommends that everyone aged 6 months and older get vaccinated against the flu annually.

Flu season typically starts in October and ends around May, with a peak in December or January. It began six weeks early this year, causing a spike in hospitalization rates.

The season is ramping up even as the U.S. continues to combat the COVID-19 pandemic and a new surge of respiratory syncytial virus (RSV), a critical illness for youth that has put a strain on children’s hospitals.

With the “triple threat” of viruses impacting children’s health care across the nation, some pediatric groups are calling on the Biden administration to declare a national emergency to free up additional resources.

As of the week ending Nov. 19, the states most affected by the flu so far this season include California, Texas, New Mexico, Colorado, Washington, Virginia and New Jersey, which are among those the CDC lists with a very high activity level.

Influenza A is the dominant virus, making up close to 100 percent of all confirmed flu cases, according to the CDC.

Of the confirmed cases of Influenza A, 78 percent are the H3N2 strain and 22 percent are the H1N1 strain.

Flu season intensifies with 6M infected in US: CDC