“For the delta variant, the R0 is now calculated at between six and seven,” [biologist and biostatistician Tom] Wenseleers says. So it’s two to three-times as contagious as the original version of SARS-CoV-2 (R0 = 2 to 3) but less contagious than the chickenpox (R0 = 9 to 10).

So why did the CDC say the delta variant was “just as transmissible as” the chickenpox?

For one, the leaked document underestimated the R0 for chickenpox and overestimated the R0 for the

delta variant. “The R0 values for delta were preliminary and calculated from data taken from a rather small sample size,” a federal official told NPR. The value for the chickenpox (and other R0s in the slideshow) came from a graphic from The New York Times, which wasn’t completely accurate.

“At the end of the day, this delta variant is much more transmissible than the alpha variant,” the official added. “That’s the message people need to take from this.” The official requested anonymity because they were not authorized to speak to the media on this topic.     

By Michaleen Doucleff reporting for NPR’s “Morning Edition” Aug. 11:  WSJ August 12, 2021

Bottom line:

• Delta variant more transmissible than Alfa Covid-19
• Get Vaccinated!

The C.D.C. seemed incapable of answering these questions. From the pandemic’s earliest days, the agency had been subject to extreme politicization and troubled by what looked, at least from the outside, like pathological clumsiness. NYT Magazine June 16, 2021

This is all excellent news, as is the finding that 99% of hospitalizations for Covid-19 are among unvaccinated people. The vaccines are as good as first heralded, even against new variants. That unvaccinated people are still being hospitalized underscores the continuing need to get as many people vaccinated as possible.

By Leslie Bienen and Monica Gandhi WSJ July 15, 2021