Children develop robust and sustained cross-reactive immunity after Covid

Re:Children develop robust and sustained cross-reactive immu... by lamontcg on Friday December 24, 2021 @05:27PM (#29678377)

Omicron's lower hospitalization rate is likely just due to vaccination and recovery from infection with Delta. Delta was transmissible enough to complete the vaccination program.

Given that Omicron has higher viral loads, shorter serial interval and shorter incubation period than Delta, it is much more likely that Omicron is more intrinsically virulent as well and would be worse if you dropped it on a totally naive population in the summer of 2019. The current population, however, is longer immunologically naive, and I think that researchers are underestimating the existing seroprevalence.

At the same time if there's still pockets of entirely unexposed/unvaccinated people out there in rural areas or something, Omicron will likely find them since it seems to largely ignore unboosted Nabs to prior infection or vaccination. Kids in colleges will be taking Omicron home for Christmas to rural families right about now and a few weeks from now we should find out how many seronegative people are left.

If it Omicron fizzles though it is going to just be that Delta didn't leave anyone immune naive in its wake.

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Re:Children develop robust and sustained cross-reactive immu... by jbd28 on Friday December 24, 2021 @07:41PM (#29679201)

It was shown in vitro to be 10x less effective at infecting lung cells vs epithelial cells (mucosal membranes). There’s more than prior immunity at play here. https://wap.business-standard.com/article-amp/current-affair...

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Re:Children develop robust and sustained cross-reactive immu... by jacquesm on Friday December 24, 2021 @06:20PM (#29678745)

Another factor (though I'm not sure how large that factor is) is that a chunk of the susceptible population isn't around any more.

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Re:Children develop robust and sustained cross-reactive immu... by lamontcg on Friday December 24, 2021 @06:26PM (#29678784)

Literal survivorship bias.

There may also be a hard-to-infect/hard-to-seroconvert portion of the population left that could practically walk unmasked through a COVID ward in a hospital and not get infected. If they exist then the seronegative proportion of the population will start to be composed mostly of them over time through "purifying selection".

This is also why I'm somewhat skeptical about all the vaccine efficacy numbers that studies are throwing around. I don't think an adequate control group exists any more.

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Re:Children develop robust and sustained cross-reactive immu... by jacquesm on Friday December 24, 2021 @06:32PM (#29678822)

That's a good point: having a control group is pretty much a must to be able to get reliable numbers on efficacy and any future vaccine or medicine is going to have to some extent work with corrupted data from day #1.

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Re:Children develop robust and sustained cross-reactive immu... by sjg007 on Friday December 24, 2021 @10:53PM (#29680235)

A bunch of kids are ending up in the hospitals at a higher rate than before so you may be right.

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