Covid (and flu) is an infection of the respiratory system beginning in the mucous membranes of the nasal system.
Confined there, these virus' are not deadly in themselves. What makes respiratory virus' dangerous is when they continue infection leading to inflammation in the lungs. It is in the lungs where hypoxia can occur leading to death. What prevents virus' from damaging the lungs is when the body mounts an antibody and T-cell response against the virus quickly to prevent further expansion. But equally as important is after the virus is eliminated, the body tamps down inflammation and restores new cell growth to replace damaged cells (from the virus & T-cell attack). Lung function throughout this process is vital.
Evolution favors people (animals in general) who have a genetic ability to keep virus' out of the lungs so that exposure to other humans respiratory virus' are not fatal and populations grow. Evolution favored receptors on our cells (especially lung cells) for vitamin D which activates both T-cells to attack a virus and also other T-cells to tamp down excessive inflammation. This is especially true in the lungs (a lot of vitamin D receptors). Without vitamin D, T-cell response to a virus and the ability to limit inflammation is greatly reduced. And (as the article below reports), vitamin D does the opposite for virus'! Virus' don't like vitamin D. They don't like the sun either.
All a vaccine can do is prep the body with an antibody response more quickly than facing the virus for the first time. T-cells are still needed to prevent widespread damage and lung inflammation. People who are vaccinated against Covid still get covid - especially if their vitamin D level is low. In fact, they are likely to be more susceptible to Covid variants than unvaccinated people who already had the disease one time. It is the vaccinated who are getting Covid over and over again as the virus mutates (Alpha, Delta, Omicron, now Ba.4, Ba.5 and on and on it will go).
But it is vitamin D (must have levels above 55 ng/ml to be fully protected) which protects against Covid (and flu generally) from getting into the lungs. And if you don't have ADE (see link above), your body through T-cell memory can handle the variants better.
Below is a summary on how vitamin D helps in preventing severe respiratory disease.
The single most important thing you can do to avoid severe respiratory viral infection (covid, flu) is to test your blood for vitamin D level and to supplement so that your blood level is above 55 ng/ml (I keep mine between 70-100 ng/ml). In addition, high normal vitamin D levels is anti-cancer as well in that T-cells are vital to cancer surveillance by the body.
(note: There is no data I have seen, NONE which documents a person hospitalized/death from Covid who had high vitamin D levels (> 55 ng/ml). In fact, all hospitalizations/death recorded where blood vitamin D was measured showed these patients had very low vitamin D levels (i.e. <30 ng/ml). I want to repeat this fact - NO ONE died from Covid anywhere in the world while having a high vitamin D blood level. All who have died and had their D level measured were deficient in D).
