Steve, you can't answer this question as it stands because it assumes the test results accurately reflect what they claim to show. We need to move past this assumption to debate the argument properly. The assumption fails for two reasons:

Not all people who test positive are actually sick with the disease.

Some people with identical symptoms do not test positive.

Essentially, the test designed to detect the virus shows the same results under a microscope for millions of people, whether they are sick or not. What is claimed to be a genetic sequence is inferred from something they cannot see. They are interpreting noise as the virus because it fits their expectations. Why do you trust the test when it has proven unreliable? Moreover, this unreliability undermines your claim that Koch's postulates have been met.