Breakthrough SARS-CoV-2 infections in 620,000 U.S. Veterans, February 1, 2021 to August 13, 2021. medRxiv https://doi.org/10.1101/2021.10.13.21264966
“The proportionate reduction in infection associated with vaccination declined for all vaccine types, with the largest declines for Janssen followed by Pfizer-BioNTech and Moderna (Figure 1).Specifically, in March, protection against infection was: 88% (95% CI, 87% to 89%) for Janssen; 92% (95% CI, 92% to 93%) for Moderna; and 91% (95% CI, 91% to 92%) for Pfizer-BioNTech. By August, protection against infection had declined to: 3% (95% CI, -7% to 12%) for Janssen; 64% (95% CI, 62%-66%) for Moderna; and 50% (95% CI, 47% to 52%) for Pfizer-BioNTech.”
If data is only to August 2021, it would only include 2 months max of Delta, which is soundly defeating all the vaccines vs. the previous variants.