Vit-D in asymptomatic and critically ill Covid-19 patients and correlation

I think this is far fetched. Many viruses are much more harmful to adults than to kids, e.g. measles.

Further, among the adults who have a bad case of COVID-19, the vast majority had some relatively serious underlying condition (which is often correlated with age, but it seems to be the underlying condition, rather than the age, that is a better predictor of bad outcomes).

Additionally: there are many countries in which D-fortified milk (and even milk consumption among kids) is not nearly as common as in the US, but the age distribution of bad COVID outcomes seems to not change.

A glass of fortified milk (only full-fat milk is commonly fortified, this is something parents tend to avoid due to the FDA fat paranoia) is only 10% of vitamin D needed per day. And it's not clear if that dose is actually sufficient even in the unlikely event that 10 glasses of milk are consumed. I, for example, take 2000 IU of vitamin D daily and my bloodwork shows vitamin D smack dab in the middle of the "normal" range. According to Kaiser Permanente this "indicates supplementation", which tells me that this "normal" vitamin D is actually not normal at all, and most people are deficient. Coincidentally I do believe I had COVID in March of this year. My only symptom was the loss of smell and taste for a couple of days. Not even a fever. I didn't pay much attention to it, since these symptoms weren't known at the time.

This is anecdata though, so it doesn't really mean anything.

It would be interesting to cross reference covid morbidity with lactose intolerance (ie. people likely to avoid milk).

Here in Sweden it's obligatory (by law)[1] to fortify some foods (dairy products) with vitamin D. Both adults and children are notorious dairy consumers. So I don't think that assumption holds.

[1] https://translate.google.com/translate?hl=&sl=sv&tl=en&u=htt...

There are plenty of cofounders to consider, the biggest one might be the transition from innate to adaptive immunity (the latter potentially mistriggering as a cytokine storm).

Robert Gallo presented [1] an interesting idea to keep the innate system boosted by taking extra doses of a vaccine (he proposes using OPV). My pet corollary to Gallo's idea is that kids may have extended protection by having been more recently vaccinated (than adults).

[1]: https://www.youtube.com/watch?v=rHvV81ZB-fk

This was published in an open-access journal called "Scientific Reports", one of many Nature-run-but-not-Nature journals currently diluting their brand. I'm not sure if the domain name confusion is deliberate or not.

https://www.nature.com/srep/about

Yes, D is fat-soluble, so it won't increase much in serum levels until the fat is saturated with it.

But your criticism doesn't necessarily check out as the average BMI of group B was actually lower than that of group A.

See page 4 of the PDF [1].

[1]: https://www.nature.com/articles/s41598-020-77093-z.pdf

Any correlation where one can change one of the variables by taking a cheap, safe pill is interesting, unless we can show which way the causality goes.

Because you tested positive.

"Being deficient in essential vitamins makes you more susceptible to a virus" and "taking this vitamin will cure you of an active infection" are two _very_ different things.

But vitamin D isn't the cure though

Citation desperately needed.