in response to one of GWB's posts... most importantly, the
CDC itself mentions this regarding US Breakthrough cases, which is very interesting:
The findings in this report are subject to at least two limitations. First, the number of reported COVID-19 vaccine breakthrough cases is likely a substantial undercount of all SARS-CoV-2 infections among fully vaccinated persons. The national surveillance system relies on passive and voluntary reporting, and data might not be complete or representative. Many persons with vaccine breakthrough infections, especially those who are asymptomatic or who experience mild illness, might not seek testing. Second, SARS-CoV-2 sequence data are available for only a small proportion of the reported cases.
These flaws in data collection at the CDC level are likely amplified when trying to collect "aggregate" data and forming conclusions ...Thus, the "conclusions" are almost certainly flawed, and cannot be used in any other than entertainment value.