As we’ve been discussing in recent days, I’ve been looking for apples to apples data on the trends of vaccine efficacy around the US. Changes are likely driven by the Delta variant. But some waning of immunity among the vaccinated could also be playing a role. So could expanding immunity among the unvaccinated – because so many of them are getting sick. That would reduce the difference in infection rates between the two groups even though protection from the vaccine remains unaffected.
Now we have some new information from Oregon.