We cannot eradicate Covid-19, but humans can help the virus grow to be more benign. To get there, we must enter the Transitional Phase, when Covid-19 transforms from pandemic to another common cold coronavirus. Understanding what a virus wants and how a virus views the world helps. With knowledge of existing human coronaviruses and basic viral/host interactions, we come to understand that herd protection—not herd immunity—is the goal. Immunity is not permanent from coronaviruses, and a vac...