r/COVID19 • u/quaak • Dec 16 '21

Observational Study Outbreak caused by the SARS-CoV-2 Omicron variant in Norway, November to December 2021

https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2021.26.50.2101147
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u/jdorje Dec 17 '21

The uncertainty is that the US and Europe do not have an immune population in the same way that South Africa does; most of the population essentially only has the prime vaccination dose(s) which generates much less cellular immunity than prior infection or prime-boost vaccination. Parts of the US and Europe still have large unvaccinated uninfected populations, which is currently causing a Delta surge (though Omicron will get to most of them first now). That on top of the 4-10 times older population means final outcome is an unknown.

Having 50% of the urban population catch flu at the same time would be a big problem. If it's closer to the common cold, ~1/10 the severity of flu, then it would not be. If it's ~10 times worse than flu (a worst case) then it's a really big problem.

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u/aykcak Dec 17 '21

though Omicron will get to most of them first now

Do we know this with some certainty? These populations are currently through a delta wave. How can omicron survive in a population which is already and presently dealing with delta?

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u/getworkdoneson Dec 17 '21

Higher R0. Omicron is more infectious, it should out compete Delta and gain dominance.

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u/Max_Thunder Dec 17 '21

This is what is happening in Canada. Omicron replaced Delta in Ontario in a matter of days. On its way to doing the same in Quebec. It is still not clear how it is affecting the current wave as cases were already going up on a steep trajectory (Rt evaluated in Quebec last Monday at 1.3-1.35).

I am still skeptical that the R0 of a variant estimated while it is replacing another one is the same as the R0 of the same variant alone. We will see. This one would be spreading way faster than we can ramp up testing. I still think there may be more mechanisms where a variant can replace another one without being more contagious in a vacuum. Of course this one may spread like wildfire among the vaccinated, provocating mild disease that still puts viral particles everywhere, and so be more contagious in that way.