… and then, after falling substantially but not nearly to pre-Delta levels, the fall has levelled off and the case numbers may perhaps be rising again.
(I don’t know what to make of this. Burning through some particularly-exposed subpopulation and then more slowly getting to everyone else? Some weird transient effect from the end of the school term?)
A couple of things that seem possibly missing from the reasoning there: 1. if time-to-hospitalization or time-to-death is more variable than time-to-testing-positive, then those later but more reliable indicators will be low-pass-filtered relative to the case numbers, which would mean that looking at early hospitalization/death numbers might make even a real decline look fake or exaggerated; 2. if the rise is all about Delta taking over and Delta is more harmful than the previously dominant strain, and if during the “falling” period the proportion of Delta in the population relative to other strains is still increasing, then that too could make the hospitalization/death numbers not fall as dramatically as the case numbers even if the latter are genuinely falling rapidly. BUT I am a very long way from being an expert, and don’t know whether the actual numbers are such as to make either of those a real issue.
(I think #2 is not a thing; almost all UK cases were Delta too early for that to be the case. But, again, not an expert.)
… and then, after falling substantially but not nearly to pre-Delta levels, the fall has levelled off and the case numbers may perhaps be rising again.
(I don’t know what to make of this. Burning through some particularly-exposed subpopulation and then more slowly getting to everyone else? Some weird transient effect from the end of the school term?)
See also: Twitter thread looking at hospitalization/death data and concluding that the big fall was mostly not real because by now we should be seeing it in those data.
A couple of things that seem possibly missing from the reasoning there: 1. if time-to-hospitalization or time-to-death is more variable than time-to-testing-positive, then those later but more reliable indicators will be low-pass-filtered relative to the case numbers, which would mean that looking at early hospitalization/death numbers might make even a real decline look fake or exaggerated; 2. if the rise is all about Delta taking over and Delta is more harmful than the previously dominant strain, and if during the “falling” period the proportion of Delta in the population relative to other strains is still increasing, then that too could make the hospitalization/death numbers not fall as dramatically as the case numbers even if the latter are genuinely falling rapidly. BUT I am a very long way from being an expert, and don’t know whether the actual numbers are such as to make either of those a real issue.
(I think #2 is not a thing; almost all UK cases were Delta too early for that to be the case. But, again, not an expert.)