The Centers for Disease Control and Prevention said Friday that 10 more children died last week because of a flu season that is showing no signs of slowing down.

The CDC said there have been 63 pediatric deaths so far, and cautioned that the flu season may not have peaked. The agency said the U.S. could be in store for several more weeks of severe influenza.

“Flu is incredibly difficult to predict and we don’t know if we have hit the peak yet,” acting CDC director Anne Schuchat said on a call Friday with reporters.

Schuchat said the flu usually peaks either around week 11 or week 20 each season, and the current flu season is at week 11.

She added that this is shaping up to be a historically severe flu season. The number of outpatient and emergency room visits because of the flu is as high this season as they were at the peak of the 2009 influenza pandemic, the CDC said.

Schuchat added that the rate of hospitalizations continues to soar.

The CDC started a new method for tracking hospitalizations in 2010. It found overall there have been 59.9 hospitalizations per 100,000 people due to the flu, compared to 35.1 hospitalizations for the previous severe flu season in 2014-2015.

Schuchat recommended that people still get the flu shot even this late in the season.

The CDC doesn’t know how effective the shot has been for this season. However, data from Canada shows that it was only about 10 percent effective against the most predominant strain of flu this season, called H3N2.

Canada has a similar flu shot formula to the U.S.

But the flu shot is more effective against other strains of influenza, such as Influenza B and H1N1. Schuchat said both of those strains are starting to pick up steam as H3N2 is starting to wane.