I see that more children are being hospitalized with Covid-19. If I recall correctly, throughout the pandemic, researchers have thought that children were more resistant to the virus because they are often exposed to other viral pathogens, and therefore often have a Type I IFN response activated (which I've taken it is very effective at preventing infection).

I'm curious to know why more children are being hospitalized now. Some possible reasons that come to mind are that the coronavirus has evolved to better subvert the Type I IFN response, or that it has evolved to be able to better infect cells that are mounting a Type I IFN response, or that children are being exposed to fewer pathogens now (than they were even recently), or that the number of children hospitalized is independent of the number of children infected.

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    $\begingroup$ Since Delta is so much more transmissible than earlier variants, it's likely that many more children are being infected than previously. More infected -> more hospitalized. $\endgroup$
    – Armand
    Aug 16 '21 at 3:04
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    $\begingroup$ Children have the lowest vaccination grade. They're also a lot less likely to keep their distance from each other. $\endgroup$
    – Mast
    Aug 16 '21 at 17:25

Right now, at least, it's not clear whether anything significant has changed biologically for children with respect to the Delta variant.

What is known for certain, however, is that Delta is very infectious, and that the vast majority of kids are still unvaccinated, either because they are under 12 and not eligible or because they are teenagers whose parents didn't feel a sense of urgency to vaccinate.

In the US, where COVID is surging and more than 70% of adults are vaccinated, just comparing vaccination rates for different age groups means that we should expect to see a far larger fraction of the infected being children than in the previous waves. There's a lot of infections going on right now, and thus as a baseline, even if the danger for any given child is the same as with the prior variants, we should expect a lot more sick kids than before.

  • $\begingroup$ Add to this the anti-mask crowd and the start of in person schooling and we will see many more sick before this thing is behind us. $\endgroup$
    – boatcoder
    Aug 17 '21 at 21:04
  • $\begingroup$ Washington Post reported on August 3rd that 57% of US adults had at least one vaccine dose. Has the number changed that much in less than a month, or is there an inaccuracy in one of these figures? $\endgroup$ Aug 17 '21 at 21:37
  • $\begingroup$ @electronpusher You are getting the figures in the article confused. Currently 59.9% of all people in the US (including children) have at least one dose. When you remove children under 18, it's currently 72.3% of adults. Children in the 12-17 age bracket are currently at 44% with at least one dose. All of these numbers were just a few percent lower two weeks ago. $\endgroup$
    – jakebeal
    Aug 17 '21 at 23:14
  • $\begingroup$ Is Delta more infectious than other variants though? Yes, it's very prevalent, but you probably wouldn't call this year's strain of influenza more infectious than last years, and the year before that and so on. So while your statement that it's very infectious is true (every SARS-CoV-2 variant is), it may mislead some people who may think that Delta is somehow worse than other variants, while it just has better fitness in the current population. $\endgroup$
    – JohnEye
    Aug 18 '21 at 0:16
  • $\begingroup$ @JohnEye Although the exact r-value isn't certain, the data so far shows the Delta variant to be far more infectious than other strains. See, for example: context-cdn.washingtonpost.com/notes/prod/default/documents/… $\endgroup$
    – jakebeal
    Aug 18 '21 at 0:37

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