Seriously sick coronavirus patients in New York state’s largest hospital system are being given massive doses of vitamin C — based on promising reports that it’s helped people in hard-hit China, The Post has learned. Dr. Andrew G. Weber, a pulmonologist and critical-care specialist affiliated with two Northwell Health facilities on Long Island, said his intensive-care patients with the coronavirus immediately receive 1,500 milligrams of intravenous vitamin C. Identical amounts of the powerful antioxidant are then readministered three or four times a day, he said. Each dose is more than 16 times the National Institutes of Health’s daily recommended dietary...