Thread by @profshanecrotty

Moderna results are out for their booster vaccines!
🔵 Boosting with same vaccine generates good antibodies against variant B.1.351
🔵 Boosting with a B.1.351 vaccine generates even better antibodies
🔵 Safe
🔵 The booster vaccine was made and tested with exceptional speed!
🧵

The reason for excitement about this is that there has been uncertainly for months about vaccine efficacy against B.1.351 (1st seen in South Africa) and similar variants. Since January I have been saying:

Moderna, Pfizer, J&J and other vaccine companies have all stated that they are developing B.1.351 boosters or similar. Today is the first public data on such a vaccine.

investors.modernatx.com/news-releases/…

Moderna did both a 'regular' boost, or a boost with a B.1.351 specific vaccine.
"Following boost,... titers...against the wild-type, B.1.351, and P.1 variants increased to levels similar to or higher than the previously reported peak titers ..."

That's excellent. Not amazing, but excellent. At those levels, I think the robustness of the maintenance of the antibodies over time is a factor. (If the levels were 10 times higher, memory kinetics would be less key)

There were multiple indications these booster approaches would work for eliciting cross neutralizing antibodies:
🔵General immunology principles
🔵 Neutralizing data from B.1.351 infected people (Sigal)
🔵 Neutralizing data from COVID cases then getting 1-dose of RNA (McGuire)

In parallel there is outstanding news from Pfizer that their "regular" 2-dose COVID vaccine has 75% efficacy against B.1.351 cases and 97% efficacy against severe/fatal disease.

https://twitter.com/profshanecrotty/status/1390089934296346626?s=20

I will take another look once the preprint comes online in a day or so.