What steps would you take in your thinking (metacognition), and how would it relate to the steps needed to follow the scientific method?

In January of 2020, the United States declared the spread of COVID-19 a national emergency. In the weeks and months to follow, we saw the global spread of COVID-19 surge.

If we were to see a surge in individuals with COVID-19 like symptoms, who also tested negative for COVID-19, what would we need to investigate to determine if this is a new strain of COVID or a different virus?

What steps would you take in your thinking (metacognition), and how would it relate to the steps needed to follow the scientific method?