Putting this here because... I sure hope they are testing for both.
A record-breaking 105 US children have died from flu so far this season
By Gina Yu, CNN
Updated 1:34 PM ET, Fri February 21, 2020
(CNN) - So far this season,105 children have died from the flu, according to data released Friday by the US Centers for Disease Control and Prevention. This is the highest number of child flu deaths at this point in the season since the CDC started keeping records in 2004, except for the 2009 flu pandemic.
It has been an “unusual” flu season with a higher proportion of children and young adults affected than the older population, according to Dr. William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center.
https://www.cnn.com/2020/02/21/health/child-flu-deaths-105/index.html
From your link...regarding kids and this year’s flu...
.... “This is the first time in 25 years where [influenza B] became so common so early,” said Dr. Buddy Creech, an associate professor of pediatric infectious diseases at Vanderbilt University Medical Center.
Neither Schaffner nor Creech know why this year’s influenza timeline is so different.
“It’s leaving all influenza virologists puzzled,” Schaffner said....
The article also suggests that it may be affecting kids who’ve NOT been vaccinated (flu shots), than those who have.