Various articles related to COVID19 and SARS-CoV-2.

Comparison of the clinical characteristics and mortality of adults infected with human coronaviruses 229E and OC43
229E was found to have a fatality rate, in those with severe enough disease to be hospitalized, of 25%. Yet, most of us are first exposed sometime in our youth, and therefore have a cold from it.

Why COVID-19 Is Here to Stay, and Why You Shouldn’t Worry About It
Rich article, well worth reading, lots of links, mentions the above 229E which has had many variants.

A human coronavirus evolves antigenically to escape antibody immunity
This is one of the links in the above article. Don't overlook it.

Sunlight and Vitamin D
Summary of everything on this topic.

49 minutes exposure needed daily when sun is 45° above horizon at noon.
Webb 2011 DOI: 10.1111/j.1751-1097.2011.00898.x

Vitamin D Wiki
Tons of assorted information, links to studies, etc.

Natural immunity vs vaccination

Necessity of COVID-19 vaccination in previously infected individuals
Not one of the 1359 previously infected subjects who remained unvaccinated had a SARS-CoV-2 infection over the duration of the study.

Large-scale study of antibody titer decay following BNT162b2 mRNA vaccine or SARS-CoV-2 infection
"Six months after BNT162b2 vaccination 16.1% subjects had antibody levels below the seropositivity threshold of <50 AU/mL, while only 10.8% of convalescent patients were below <50 AU/mL threshold after 9 months from SARS-CoV-2 infection."

Immunological memory to SARS-CoV-2 assessed for up to eight months after infection
Published December 2020. Stable IgG levels over 6+ months, B cell levels stable, etc.

Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: reinfections versus breakthrough infections
The Israeli study finding 13 times higher risk of re-infection in vaccinated versus recovered.

Effect of vaccination and of prior infection on infectiousness of vaccine breakthrough infections and reinfections
Compared to immune-naive first infection, Ct cycles were 1.3 times higher for breakthrough in Pfizer vaccinated and 4 times higher for reinfection in recovered. (e.g. naturally immune who got reinfected had orders of magnitude lower viral load)

Vaccine Effectiveness

COVID vaccines cut the risk of transmitting Delta — but not for long
After three months, with AZ vaccine, chance of passing on infection similar to someone unvaccinated; Pfizer also had marked decrease.

Pandemic Preparedness Exercises

Government and institutional responses weren't spontaneous.


Asymptomatic heart abnormalities following COVID19 detectable only via MRI

Study of monthly 25(OH)D levels in 588 apparently healthy Slovaks from 2016

Microneedle array vaccination quantum dots