Flu cases are on the rise across the U.S., including in New Jersey.

According to the Centers for Disease Control and Prevention, 19 states reported high levels of flu activity this week. New Jersey was among them.

That's up from only nine states last week.

A total of 13 children have died from the flu so far this season.

The CDC says children are vulnerable to H1N1, which is this year's predominant flu strain.

Flu season typically continues through May.