Thread by @profshanecrotty

The ‘leaked’ CDC presentation summarizes a lot of key Delta variant data, but it takes an unusually dark interpretation. Overall, the report basically restates what we have known for a month from England:

🔵 RNA vaccines still work ~88% against Delta cases (and even better against hospitalizations).
🔵 Delta is much more infectious (i.e., transmits faster)
🔵 Delta has faster 🔝 viral loads.

Yes, Delta variant is trouble! And it is really trouble for unvaccinated people

“Although it’s rare, we believe that at an individual level, vaccinated people may spread the virus, which is why we updated our recommendation,” according to the federal health official, who spoke on the condition of anonymity because they were not authorized to speak publicly.”

As noted above, the presentation took an unusually dark interpretation of the data. e.g., highlighting some of the worst numbers, and, for example, highlighting total infections in vaccinated people (PCR+) instead of symptomatic infections (COVID).

The most unexpected part was unpublished data of a Massachusetts outbreak where viral loads were equal in vaccinated and unvaccinated people. That would be surprising.

Ct and viral load interpretations have been notoriously inaccurate in reports for variants over the past 8 months. Lots of experiment controls have to be in place, so I currently put more weight on other data. It’s 1 unpublished report.

And, of course, since most vaccinated people are protected from infection, the majority of transmissions are by unvaccinated cases. And that’s really what we’ve seen in America this summer.

The CDC slides:
washingtonpost.com/context/cdc-br…

So, again: yes, Delta variant is trouble! And it is really trouble for unvaccinated people
🔵 RNA vaccines still work ~88% against Delta cases (and even better against hospitalizations).
🔵 Delta is much more infectious (i.e., transmits faster)
🔵 Delta has faster 🔝 viral loads