Your avatar suggests you know something about these things. 
More of a biochemist than cell biologist. My daughter made that cell for me. She’s so cute.
In terms of viral diseases spread by snot and poop from person to person? Not so much so. Oh there are infectious diseases more prevalent among children in poorer countries, ones with worse outcomes, but barring vaccination programs the viral childhood illnesses vary little in timing or frequency.
A good example is rotavirus (major cause of viral diarrhea). Prior to wide vaccine availability almost all kids got rotavirus infections one to several times by age five - across the world and across all socioeconomic strata. In developed countries children frequently were admitted dehydrated and had a day or so getting IV fluids; in poorer nations many died as access to even adequate oral rehydration management was uncommon. But kids got it everywhere pretty much the same because all kids are exposed to each others poop.
Specific to the common cold causing hCoVs? Pretty similar from Israel to Australia to Nepal to China to the Netherlands. Kids get them frequently. Yes more crowded with kids more common but across cultures a frequent childhood set of infections. Because pretty much all kids are exposed to each others snot a lot.
For snot and poop germs the exposure frequency goes other kids highest, adults who work closely with large groups of the kids next, then parents, then last other adults.
To highlight from Israel the age distribution:
And from China:
And the other, the third one listed, immunological memory, as quoted earlier, and even bolded, which is the one that the data actually explicitly supports and only one of the three which it supports explicitly:
The superior innate immunity hypothesis runs into a difficulty as the prime explanation precisely because innate immunity is non-specific. It does not explain why kids are specifically so much less likely to get ill with COVID-19 compared to many other germs. Superior innate immunity to the degree it exists should apply to large degrees to all bugs across the board.
51,810,343 total cases
1,279,546 dead
36,395,204 recovered
In the US:
10,559,184 total cases
245,799 dead
6,601,331 recovered
Yesterday’s numbers for comparison:
Kids get less sick from most of the “childhood diseases”, like mumps, chickenpox, etc. Kids get less sick from hepatitis A, too. In places where it is endemic, almost no one gets seriously ill from hep A because they all catch it and develop immunity as children. (At least, that’s what my father, a world renowned liver doctor, told me when I was worried about exposure to my kid.)
It’s not true that kids get less sick from all diseases, but they get less sick from enough diseases that it seems unremarkable if this is another such disease.
The 7 day moving average of covid deaths in the US surpassed 1000, four days after it broke 900.
The test positivity rates in South Dakota and Iowa are above 50%.
FWIW, when I write “many other” I am not making any claim of “all diseases” - but your claim of most of the "childhood diseases? Chickenpox yes, primary chickenpox as a teen or adult is much worse than primary chickenpox as a child. Hepatitis A too. Mumps, not I am aware of. Really not too many, the ones that do are in fact pretty remarkable in that way, and not established that superior innate immunity in childhood is the reason for those few exceptions, any more than established that some innate immunity deficiency is the reason that certain germs relatively only cause significant disease in childhood.
Again, I do not cross superior childhood innate immunity off the list but as of now there is little* to put out there to support the speculation, and growing evidence for the frequency/recency hypothesis**.
*Evidence for it is the association of vaccines that boost the innate response with improved outcomes in adults. One can argue perhaps that initial response to a novel organism depends on the innate response more, and that kids are built better for novel exposures, since everything is initially pretty novel to them, while adults give up some of that skill having seen most bugs before. That makes some sense.
** Solid evidence that worldwide children have the most frequent and recent exposures to the common cold causing hCoVs compared to adults, evidence that children have roughly an order of magnitude greater frequency of pre-existing cross-reactive antibodies, and a pattern of IgG predominant response to SARS-CoV2 which is consistent with a response based on past similar enough exposure. Here’s from the Science article:
And those antibodies (seen in a majority of kids from other recent/frequent hCoV infections and less often in adults) alone (nevermind T-cells) have proven impact in cell culture at least. Not as potent as antibodies from resolved actual SARS-CoV2 do, but significant. Also from the article:
Shit! Have they run out of tests?
Here in Iowa you have to jump through hoops to get tested. And many don’t wear masks. And our Gov. refuses to do more than set a few guidelines. No mask mandate for Covid Kim.
So tons of asymptomatic people and loads of symptomatic but no fever people walking around spreading the virus merrily.
From the DJT playbook:
Bolsonaro says Brazilians must not be ‘sissies’ about coronavirus, as ‘all of us are going to die one day’
Brazil should stop being “a country of sissies,” President Jair Bolsonaro said Tuesday as the country’s coronavirus death toll surpassed 162,000 — the second highest in the world, behind only the United States.
“All of us are going to die one day,” the far-right leader told reporters at a news conference, Reuters reported. “Everyone is going to die. There is no point in escaping from that, in escaping from reality. We have to stop being a country of sissies.”
Bolsonaro used the Portuguese word “maricas,” an offensive slang term for gay people.
The first cruise ship to start sailing in the Caribbean has a positive test.
It’s more terrifying. They’re doing this because they don’t have enough medical staff to care for patients without the asymptomatic ones working, and there’s nowhere left to ask for volunteers from because everywhere is overwhelmed with new hospitalizations. Tonight I heard on the news that ND has no more open COVID beds. They’re full up.
There are a lot of states looking at that reality. Saturday an author I follow on Twitter, whose husband works in the ER at a major Denver hospital, said that their COVID wards were full and the other nearby hospitals were almost there, too. They figure by the end of the week, Denver will have no COVID beds remaining.
The situation isn’t helped by the shortage of trained ICU personnel that existed before COVID and the loss of many during the course of the pandemic.
52,440,433 total cases
1,289,730 dead
36,676,552 recovered
In the US:
10,708,630 total cases
247,397 dead
6,648,679 recovered
Yesterday’s numbers for comparison:
A few things to note today:
Texas became the first US state to have more than 1,000,000 total cases.
The US has now had two consecutive days with more than 142,000 new cases and more than 1400 deaths.
Today marks 9 months since I started posting numbers; here’s what things looked like on 11 February:
Feels like a million years ago.
Another one chiming in to thank you for your diligence Bo. Not good news, but news that needs to be heard.
In the past few weeks Austria has gone from the poster child of successful Covid-19 containment to one of the hardest-hit countries in the EU in terms of new cases per capita. (The current rate is 6000 new cases per day, in a country with almost 9 million people.) And this is rather puzzling to me, since it doesn’t seem that the containment measures here are all that different from those being implemented in other EU countries, and there doesn’t seem to be any significant public resistance to the restrictions—if anything, people are demanding they be tightened even further. In response, the current lockdown was strengthened yesterday by forcing shops to close an hour earlier (19:00 instead of 20:00). And today and tomorrow the government will be discussing whether to more fully close schools. Currently only high schools and universities are on distance learning, though it’s proposed that the rule be extended to elementary schools. This would mean that elementary school students must remain at home unless their parents are unable to care for them there.
Bo, I also want to express my appreciation for your daily reporting.
This seems common, but I do not understand this. It seems like restricting hours just forces more people into the shop at the same time. How is that supposed to help?
New Jersey is closing bars & restaurants at 10pm now. But this is only step one. I don’t think that is anywhere near enough to stop the spread and soon they’ll be shutting down inside eating & drinking again.
NJ Gov. Murphy also suspended interstate games and tournaments involving sports. This seems too little. Time to suspend interschool sports.
I’ve wondered the same thing.