wow the video I included has been removed from youtube !
no there is evidence it will cure covid-19 as well as many other viral infections especially viral pneumonia.
taking MASSIVE DOSES when sick is essential if you want to significantly benefit. the point is that the vitamin C is not just helping your immune system, it acts directly as an anti-viral in the blood stream and possibly within cells as well. Otherwise I couldn't explain why its so amazingly effective against viral pneumonia including in patients in such a weakened condition that the dramatic improvement they experience couldn't possibly be attributed in the main to their own immune system.
I dont pretend to be an expert, but Dr. Chen (video removed) claimed that vitamin C causes the production of hydrogen peroxide in the body and this is main reason for its direct antiviral efficacy, beyond what help it provides to the patients immune system.