These plots result from the analysis of the Phase 3 trial data of Moderna’s 2-dose mRNA-based vaccine, reported in this article.
Moderna did a remarkable job of seeking out people with co-morbidities that put them at additional risk of contracting the disease. As a consequence, they wound up with 30 “severe” COVID-19 cases in their placebo group (and 0 in their vaccine group!), resulting in strong evidence of protective efficacy against severe COVID-19.