If they could not find covid in the 1500 samples, and CDC won’t give anyone covid virus samples, then how do they know what they had, although most of the 1500 turned out to be ‘flu A & ‘flu B.
Analogy:
suspect $100 bill (1500 samples)
Real $100 bill (covid virus sample)
They do have a real flu A & flu B to compare to, when checking for those virii.