This past week, high flu activity was reported in 25 states, New York City, Washington, D.C., and Puerto Rico, according to the Centers for Disease Control and Prevention.
The CDC estimates the flu has caused 4.6 million illnesses, 39,000 hospitalizations and 2,100 deaths so far in the 2019-2020 season.
The deaths include 22 children, three of those occurring between Dec. 15 to Dec. 21.
The percentage of deaths associated with flu and pneumonia has increased to 5.7% for that week, but the CDC said this remains below the epidemic threshold of 6.7%.
All regions of the country are seeing elevated flu activity, and the states most affected are: Alabama, Arizona, Colorado, Connecticut, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland, Minnesota, Mississippi, Nebraska, New Jersey, New Mexico, North Carolina, Oklahoma, Oregon, South Carolina, Tennessee, Texas, Virginia, Washington, and Wisconsin.
National levels of flu-like illness activity are continuing to increase and have been elevated for seven weeks.
The CDC does not know exactly how many people get sick with flu each year, as some people who get sick don't get tested.
Even in the middle of the flu season, the CDC said it is not too late to get vaccinated.