The part of my extended family, 8 of us, that resides locally all had it in February/March of 2020. all but one, my son-in-law, took a measured megadose of vitamin D3 as soon as we had symptoms. All of us had been taking daily D3 for years and have totally avoided colds and flu in that time. Getting unexpected symptoms induced the immediate turn to the megadose which two of us had begun the D3 dailies with due to having been very sick with the version of flu then going around. All of us were completely over it in 8-10 hours. Except wife and SIL. Wife got pneumonia and it was cured of that in a few days when her doc prescribed an asthma inhaler and antibiotic. SIL was a pharmacy tech and would not take anything not prescribed by his physician so he was in bed for a week before he recovered.
i’m curious as to what you call a “megadose” ...