OP here following up - the data collection does seem to be all over the place. Does this line from the article basically mean they're admitting there's no difference?
"The findings in this report are subject to at least five limitations. First, combining unvaccinated and partially vaccinated persons resulted in lower IRR and VE estimates. Second, variable linkage of case surveillance, vaccination, hospitalization, and mortality data might have resulted in misclassifications that could influence IRR estimates; no substantial differences in ascertainment of outcomes by vaccination status were noted in jurisdictions that were able to assess this."
Anytime there's a merging of huge databases, many cases cannot be linked by identifiers. As the article notes, all the cases not cleanly identified as fully vaccinated were not thrown out of the analysis, but added into the "unvaccinated" category.
All participating jurisdictions had established processes for linking case surveillance and vaccination data from state/local immunization registries; this method usually assumes that cases among persons not matched to the registry are among unvaccinated persons. >
OP here following up - the data collection does seem to be all over the place. Does this line from the article basically mean they're admitting there's no difference?
"The findings in this report are subject to at least five limitations. First, combining unvaccinated and partially vaccinated persons resulted in lower IRR and VE estimates. Second, variable linkage of case surveillance, vaccination, hospitalization, and mortality data might have resulted in misclassifications that could influence IRR estimates; no substantial differences in ascertainment of outcomes by vaccination status were noted in jurisdictions that were able to assess this."
Or am I not understanding correctly?
Anytime there's a merging of huge databases, many cases cannot be linked by identifiers. As the article notes, all the cases not cleanly identified as fully vaccinated were not thrown out of the analysis, but added into the "unvaccinated" category.
Typical ploy of CDC in dealing with missing data.