Flu activity across the United States is beginning to decline, according to new data from the Centers for Disease Control and Prevention, but emergency room visits among school-aged children are increasing.

The CDC estimates at least 19 million flu illnesses, 250,000 hospitalizations, and 10,000 deaths so far this season. Seven states are reporting very high flu-like activity, while 23 states remain in the high category.

Twelve flu-related pediatric deaths were reported this week, bringing the season total to 44. Last season saw a record 289 child deaths from influenza, the highest since tracking began in 2004.

While overall flu levels are decreasing, ER visits for children ages 5 to 17 rose compared to last week, though hospitalizations stayed stable. Experts say the flu season started earlier than usual and warn a second surge later in winter is still possible.

Most cases this season are linked to a new strain known as subclade K, a variant of the H3N2 influenza A virus. The current flu vaccine is considered a partial mismatch for this strain but continues to provide protection against severe illness, especially in children.

Vaccination rates remain modest, with about 45.6 percent of adults and 44.2 percent of children vaccinated as of January 10. Doctors stress it is still worthwhile to get vaccinated and recommend basic precautions such as handwashing, avoiding crowded spaces, improving ventilation, and masking when appropriate.