Thursday, December 30, 2021

Experimental Data Are Accruing That Omicron Exhibits Decreased Lung Infectivity.


Friday Dec 31/21 - See Update at the bottom of the post

As we noted in our last round-up post, even if the omicron variant really does generate, on average, less severe symptoms than the delta variant, the shear number of infections due to increased transmissibility will cause significant issues for healthcare systems.

Having said that, the experimental data are piling up that, different from the situation in upper airway, omicron does not infect the lining epithelial cells within the lung nearly as well as previous versions of the virus.

Eric Topol has summarized and cited those data which has been generated by multiple reputable groups:

What does this mean? Well, if it translates to the clinical/human realm it could mean significantly reduced COVID pneumonia - the bad acute* outcome of the virus.

Thus, if we can flatten the hospitalization/ICU curve in the short term by decreasing transmission while we get vaccinations amongst kids and boosters up for the vulnerable at the same time, the omicron variant could, ultimately, help us see and move toward the lights at the end of the long term tunnel.

However, again, in the short term we've got to work to decrease transmission to prevent our healthcare systems, and stretched-to-the-breaking-point healthcare workers, from being overwhelmed.

Please note that
I am not a clinician or an epidemiologist...However, I do have some expertise in epithelial cell biology - thus, the key here is how well the experimental data translate to the clinical realm...
*Please also note that, in the case of chronic, long COVID, the clinical situation is not yet clear with respect to omicron for obvious timeframe reasons.
And, just because it continues to bear repeating given that it seems to get lost in the media shuffle...While vaccination does not prevent infection/transmission of the omicron variant it is still doing a great job of decreasing hospitalization...Hugely (scroll down a little).
Update, Fri Dec 31st...And here is an interesting pre-print, with extensive experimental data and solid analysis, from a group in Glasgow. They conclude that the omicron variant has subtly, but importantly, shifted its favourite way to get into cells (from ACE-2/TMPRSS2 cell surface binding/fusion/insertion to endosomal fusion/engulfment)...This could, perhaps, contribute to the upper vs. lower airway infectivity differences of this variant (i.e. the mechanism leading to a change in cellular 'tropism'/preference for infection).


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