[bodono]

For me it was at the end of very mild flu-like symptoms (general malaise, sleeping a lot etc.). It's possible I was still contagious when I lost my smell and taste so people should probably self-isolate if they experience the same. Though my guess from personal experience is that this is a lagging indicator and possibly anyone with this has already been infectious for a while.

[makomk]

This was actually the UK government's justification for not including it on the list of symptoms that they asked people to self-isolate for initially - even though it was fairly specific to Covid, they reckoned it appeared too late in order to be all that useful as a criteria to get people to self-isolate. Notice also that the article doesn't say anything about when the symptom appears.