The difference is H5N1 infections have mostly happened in predictable and (importantly) rural places. That is, among people working directly with the animals i

The difference is H5N1 infections have mostly happened in predictable and (importantly) rural places. That is, among people working directly with the animals impacted. Covid, on the other hand, had few precursors and hit in a population dense area (Wuhan). It does not help that for a fairly significant portion of the population covid was near symptomless. H5N1 has been much more severe when it hits humans. That said, it's not impossible that a variant of H5N1 that escapes will do so because it's more covid like in that it doesn't look or act much worse than a common flu in the first few infected.