[Press release – not published yet] A phase 3 trial with more than 10,000 participants showed a booster dose of the Pfizer/BioNTech vaccine had an efficacy of 95.6% against disease; there were 5 cases in the booster group and 109 cases in the non-boosted group, not classified according to severity.

Pfizer and BioNTech Announce Phase 3 Trial Data Showing High Efficacy of a Booster Dose of Their COVID-19 Vaccine

Commentary: Booster dose of Pfizer/BioNTech coronavirus vaccine shows 95.6% efficacy in Phase 3 trial, companies say – CNN

Commentaries on Twitter

This will presumably mean everyone gets boosters early next year. That’s great, because they do work. Except it’s likely to be boosters for rich countries at the expense of primary vaccination for poorer countries. You won’t stop the pandemic when half the world is unvaccinated https://t.co/F31DMSI2zf

— Niall Conroy (@NICU_doc_salone) October 21, 2021

The 1st randomized trial of a booster (3rd) shot in 10,000 people, placebo-controlled, shows 95.6% efficacy, with 5 cases (Pfizer vaccine) vs 109 in placebo group, Delta variant, broad benefit across age groups https://t.co/TQpF35d8Jk pic.twitter.com/3RkqvXNfsU

— Eric Topol (@EricTopol) October 21, 2021