Possible ADE or OAS Showing in COVID-19?

Vaccinated people infected by Delta are more likely to be hospitalized than unvaccinated people by Alpha. The statistical power of this study isn't great, but it implies that vaccinated people are more likely to need hospitalization. Ware the confounders.

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(21)00475-8/fulltext

Reading the full paper, we find 1.9% of unvaccinated Alpha infectees required hospital admission. 2.2% of unvaccinated versus 2.3% of vaccinated Delta infectees required it, and 3.4% of vaccinated Alpha infectees required it.

Thus, strangely, vaccination appears in these findings to increase the risk of hospitalization or emergency treatment required. The statistical power of these findings isn't very great because of too few hospital admissions amongst vaccinated infectees, and bear in mind we vaccinated people at higher underlying risk first and more thoroughly and the propensity of people who have been vaccinated to also be more likely to seek medical care. Basically, I think the numbers are probably roughly accurate, but badly distorted by known confounders. But do those confounders explain everything?

This odd finding was not directly addressed by the authors, who pointed to the paucity of the data, and many other studies have shown vaccination reduces the absolute risk rate in most individuals.

A possible contribution, which I favor due to its consistency with the observation that re-infections are generally more severe than first infections, where the confounder is damage from the previous infection rather than population differences, is that OAS and ADE are showing now that antibody titers from initial inoculation are wearing off and ADE can manifest itself, but know that that opinion is far outside the present scientific consensus.

The UK data also contrasts with the Indian data, where B.1.617.2 resulted in a much more dramatic wave. The UK's better development and higher vaccination could both be expected to lengthen the wave's periodicity, and we should expect the same too, but we don't know yet what the difference in the area under the curve will be. Any OAS or ADE would be more visible in this data comparison than in one country's hospitalization data. The area under the curve will be critical to watch, but will have its own confounders, as India's data is especially poor.

My alternative explanation is countered by the apparently greater magnitude of Alpha-infected vaccinees requiring hospitalization than Delta-infected vaccinees relative to unvaccinated people, which would not be in keeping with the slightly greater antigenic distance between Delta and the vaccines than Alpha and the vaccines. The difference in antigenic distance combined with the poor statistical power really isn't great enough to conclude anything at all based on these findings, though.

Anyway, the main takeaway and finding of the study is that Delta and comorbidity equal far more hospitalizations. I conclude we should expect more hospitalizations this winter than last year.

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