While current flu shots need to be updated each season, scientists are finding new ways to make vaccine that could last much longer and cover more strains.

So, we held onto each other for dear life, like nothing would ever change, until we couldn’t hold on any longer, and we moved ...

Swipe the graphic on mobile, or click through on desktop, to follow a simplified inside-the-body view. Illustrative only. Measles is typically spread through the air. In this simplified view, virus ...