Ed Yong in The Atlantic:
Fifteen months after the novel coronavirus shut down much of the world, the pandemic is still raging. Few experts guessed that by this point, the world would have not one vaccine but many, with 3 billion doses already delivered. At the same time, the coronavirus has evolved into super-transmissible variants that spread more easily. The clash between these variables will define the coming months and seasons. Here, then, are three simple principles to understand how they interact. Each has caveats and nuances, but together, they can serve as a guide to our near-term future.