It means that most of those genetic variants don't change which proteins are coded for (the genetic code is redundant) and the remaining ones don't make any difference to disease progression. Well, there was one mutation in Singapore where one of the non-structural proteins got knocked out creating a strain that was less virulent but better able to hide from the immune system. Zoonaotic diseases usually become less virulent over time in general and a strain like that might become dominant after a number of years. But don't expect any noticeable changes in during the current outbreak except maybe in a few small pockets.
The ambiguity I was addressing was grammatical, not biological.
"now significant" could be a typo for "known significant", "non-significant", "no significant", "not significant", and possibly others, including not being a typo at all.
Likewise "significant" itself could mean different things in this context. E.g. phenotype neutral mutations can be highly informative when tracing origins, mutations in "non-coding" regions can have huge regulatory effects, etc.
I agree that your interpretation of the post to which I responded is plausible, but it's not the only one.
