The 3 Simple Rules That Underscore the Danger of Delta

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.

1. The vaccines are still beating the variants.

The vaccines have always had to contend with variants: The Alpha variant (also known as B.1.1.7) was already spreading around the world when the first COVID-19 vaccination campaigns began. And in , they have consistently lived up to . The vaccines from Pfizer-BioNTech and Moderna reduce the risk of symptomatic infections by more than 90 percent, as does the . Better still, the available vaccines slash the odds that infected people will spread the virus onward . In the rare cases that the virus breaks through, infections are generally milder, shorter, and lower in viral load. As