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.
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)
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.