According to the CDC, influenza is in its peak season as the virus is spreading at a high rate in 40 states, reports.

Influenza A and B, are spreading at a rate of 12,000 cases per week, though that number is likely much higher because many adults do not see a doctor for what’s perceived to be a common cold.

Influenza has been blamed for 15 child deaths since mid-January, the CDC reported. The number of adult fatalities in the same time period was not available.

The CDC said flu activity is “high to extremely high” in 15 regions of the country. New Jersey, Kansas, Missouri, Oklahoma, Pennsylvania, New York and South Carolina are among the states with the highest rates of flu or flu-like illnesses.