I have never read of a confirmed Covid-19 case where the active virus was gone in 72 hours.

I think the typical times are:
3 to 7 days after initial virus entry into the body until any symptom is felt in “severe” cases.
7 to 21 days until virus replication stops, or death of the patient.
In some patients virus replication went on longer than 60 days.

It might be more accurate to refer to Covid-19 as the
“Bat Cold” that typically lasts 14 to 28 days and kills on average 5 out of every 1000 persons infected.