This statement assumes that death is the only bad outcome from COVID that sufficient Vitamin D3 levels prevent.

Death is useful as a metric because, unlike other health outcomes, particularly quality of life ones, there's no element of subjectivity.

Another useful aspect of death as a metric, is that it is the most widely reported (as compared to, say, maximum fever, amount of ventilation required, days in hospital, lasting anosmia, etc. etc.)

You could measure days of hospitalization too, I would suggest both vaccine and Vitamin supplements if there are no side-effects.

It appears that with COVID, the proximate cause of death is often mis-coded, for financial reasons.

No. The statement is making a statement on deaths. You are implying this.

For the overwhelming majority of people that is the only bad outcome. Severe conditions like ARDS are rare, but also correlate with Vitamin D deficiency even outside of the pandemic (https://pubmed.ncbi.nlm.nih.gov/25903964/). As for other symptoms that are being lumped together under the label “long COVID”, their incidence seems low, the severity is usually low, and nearly all conditions disappear over time. Some have suggested that perhaps those lingering effects are no different than a typical cold or flu, except this time we are all focused on this issue and noticing these things.

Personally I am not convinced that the young and heathy need to treat COVID specially. This is a pandemic of the old and unhealthy more than anything.

> Severe conditions like ARDS are rare

Polio was lethal in less than 1% of cases, and caused severe disability in a small fraction, too. Yet people didn't go into hysterics when asked to make a relatively larger sacrifice (the polio vaccine was far less safe than modern ones) for their country.