This is another really great reason why the herd immunity threshold is lower than it has naively been claimed. If the effect is as large as TFA says then the threshold is actually much lower than the ~60% level.
This has a big impact on the estimated death rate for achieving herd immunity. The other factor in that estimate is the CFR which is also plummeting over the summer, although there’s reason to believe CFR could go back up somewhat in the winter depending on how much the gain was environment versus how much is due to better treatment protocols and therapeutics.
For example, if the immunity threshold goes from 60% -> 20% and the CFR goes from 5% -> 1% the estimate death toll is reduced to 1/15th (6.6%) of the original estimates.
This has a big impact on the estimated death rate for achieving herd immunity. The other factor in that estimate is the CFR which is also plummeting over the summer, although there’s reason to believe CFR could go back up somewhat in the winter depending on how much the gain was environment versus how much is due to better treatment protocols and therapeutics.
For example, if the immunity threshold goes from 60% -> 20% and the CFR goes from 5% -> 1% the estimate death toll is reduced to 1/15th (6.6%) of the original estimates.