Expect the Unexpected From the Delta Variant
This much is clear: The coronavirus is becoming more transmissible. Ever since the virus emerged in China, it has been gaining mutations that help it spread more easily among humans. The Alpha variant, first detected in the United Kingdom last year, is 50 percent more transmissible than the original version, and now the Delta variant, first detected in India, is at least 40 percent more transmissible than Alpha.