This week’s update from Washington State showing vaccine breakthrough cases and which Sars-CoV-2 variant is causing them up to 15th September 2021. The Delta variant continues to be the leading cause of breakthrough infections in the state, however a big drop in the number of cases being sequenced means that this data doesn’t have much statistical relevance to the actual number of breakthrough infections occurring.
The data might, however, be a useful indicator of the rising importance of new variants in the future, and on that basis we will continue to publish the information
