All strains of flu virus share the same active surface proteins for entering host cells, but Covid-19 has different ones. Also, it has very different organization of its RNA strands. It is unlikely to be a recent mutation of any existing flu virus; too evolutionarily distant. It could be a simple mutation of a bat virus though, so they say.
They are both other words for RNA virus.
All strains of flu virus share the same active surface proteins for entering host cells, but Covid-19 has different ones. Also, it has very different organization of its RNA strands. It is unlikely to be a recent mutation of any existing flu virus; too evolutionarily distant. It could be a simple mutation of a bat virus though, so they say.