We don't know for sure if vitamin C will prevent or cure COVID-19. But it is very likely that adequate vitamin C (with other nutrients essential for the immune system) can help prevent infection by this virus, like other viruses, and that IV-C can help cure this viral pneumonia, like other viral pneumonias.
I'm a board-certified physician, and I have a Ph.D. in molecular biology. I've had to use viruses in the lab to further study of metabolism (adenovirus, to be exact). I know scientific method, I know how to parse the junk science from the legitimate science.
You are trying to say just because there isn't evidence AGAINST Vitamin C working, that it COULD work. On the scientific grading scale, that's not evidence in favor of your conclusion. But in psychology it is called a "rationalization" - i.e. coming up with a borderline plausible argument to try to justify one's viewpoint instead of looking objectively at the evidence.
One month ago this forum was ABUZZ with the same arguments regarding hydroxychloroquine. And to be blunt, there was a lot more evidence that it could be a viable treatment against COVID-19 than what you have laid out for Vitamin C. One month later, we see how that has turned out (overwhelming evidence that it does NOT help, and that there are a large number of people with significant side effects).
I would LOVE for something as stupid simple as Vitamin C to be a cure-all for COVID-19. The problem is this is the proverbial "boy that cried wolf" story. Over the past 20 years Vitamin C has been proposed as a treatment for many many different infections. Different groups and governments have poured hundreds of millions of dollars into research into Vitamin C (and D, for that matter). The overwhelming conclusions are that . . . it's a Vitamin. You don't have enough, you have a MILD predisposition toward infection. You are WAY under on Vitamin C, you get scurvy. These are not new findings. We have know this for decades, and all the money spent did not further that knowledge base.
The difference between a trained scientist, and a lay person is that a scientist knows how to read ALL the literature on a subject, evaluate both sides of the argument, and weigh the evidence accordingly and plan out experiments to answer any questions that are unanswered. The lay person just reads one article (or more likely, one TITLE of an article) and forms a ROCK-SOLID opinion based upon that single piece of information, that most likely confirms some bias they already have.
I STRONGLY get the "holistic medicine is better" vibe from you, and that taints anything you could possibly say here. What is worse is that the "studies" you have presented really are not very good in their design. They are either case series (the weakest of all evidence in medical field because they are small in number of subjects) or on-going studies that are not double-blinded and randomized.
And before you tell me that I'm in bed with "the man" and paid off by big pharma, etc. I'll stop you right there. I left medicine after the *sugar*-show that it turned into due to Obamacare. I am still board certified, licensed, and keep up with the latest research, but I do NOT take a penny from anyone for anything medically-related. I run a business, un-related to the health sciences, and my home life is all the better for it.
If you want to super-juice on Vitamin C, have at it. I won't recommend against it because (unlike hydroxychloroquine) there are no harsh side effects like hydroxychloroquine had. You might get some flushing, headaches, nausea, vomiting, diarrhea, etc. but your heart will keep ticking and you will keep breathing. Just don't pimp it out UNTIL the HARD DATA is in. And contrary to what you are saying the HARD DATA is definitely NOT in to support this as a COVID-19 cure-all, preventative, or treatment.
