(CNN) As flu reaches high levels in New York and other parts of the Northeast, this season has set a tragic record for children.
The US Centers for Disease Control and Prevention says 27 children in the United States have died of the flu so far this season. That's the highest number of child flu deaths at this point in the season since the CDC started keeping records 17 years ago.
Flu struck early this season, starting in the Southeast, with Texas, Georgia, Louisiana, Alabama and Mississippi experiencing the highest level of flu activity by mid-November.
Now New York, Connecticut, New Jersey and Pennsylvania have reached that level, according to the latest CDC map.
Doctors there say they're seeing unusually large numbers of flu patients for this time of year. NYU Langone Health, for example, had 270 flu patients, adults and children, in their emergency rooms and clinics in Manhattan and Brooklyn the week of December 29.
"This is usually what we see in February or March, not late December or early January," said Dr. Jennifer Lighter, a pediatric infectious diseases physician at NYU Langone's Hassenfeld Children's Hospital.
"It's been a bad season already," added Dr. Adam Ratner, another NYU pediatric infectious disease physician.
Ratner noted that so far this season he has had patients who've developed life-threatening pneumonias and needed surgeries to drain abscesses in their chests -- and most of these children were perfectly healthy before they got the flu.
"These weren't kids who were immune compromised or anything like that, but they've ended up on ECMO," Ratner said, referring to a life support machine.
"When you see this in well kids, it's something that's always surprising and frightening," he added. "And it's sad because the vast majority of these kids with these severe influenza complications were not vaccinated against the flu this year."
If flu continues along its current trajectory, it could become one of the worst seasons in decades, Dr. Anthony Fauci, director of the National Institutes of Allergy and Infectious Diseases told CNN.
Fauci pointed out a CDC graph to compare the current flu season to two of the most severe in recent decades. In the graph below, designed by CNN based on the CDC data, the red line indicates flu activity from September 29 through December 28. The other lines show the 2014-2015 and 2017-2018 flu seasons, two of the worst in recent decades.
"Hopefully this turns around and comes down, but if it continues on the trajectory it's on, it's not going to be good," Fauci said.
Since the worst may still be yet to come, it's a good idea to get a flu shot if you haven't already. It decreases the chances you get the flu, and even if you do get it, you'll be less likely to suffer potentially fatal complications.