How did they conclude that this flu is different from every other flu?

“There are fundamental differences between viruses and vesicles: Viruses can replicate and vesicles cannot,” Margolis said. “But there are many variants in between. Where do viruses start, and where do extracellular vesicles start?”
https://www.quantamagazine.org/cells-talk-in-a-language-that-looks-like-viruses-20180502