Five years ago, a cluster of people in Wuhan, China, fell sick with a virus never before seen in the world.The germ didn't have a name, nor did the illness it would cause. It wound up setting off a ...

Covid-19 was never just another cold. We knew it was going to stick around and keep changing to try to get the upper hand on our immune systems. But we've changed, too. Our B cells and T cells, ...