In establishing the coronavirus as being the cause of SARS. The scientists needed to be certain that it satisfied Koch’s postulates

Koch’s postulates are the following:

• The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.
• The microorganism must be isolated from a diseased organism and grown in pure culture.
• The cultured microorganism should cause disease when introduced into a healthy organism.
• The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.

With the cause of the infection identified as the corona virus progress could now be made in creating tools to diagnose and treat the disease.