The downside or risk of doing this is basically nil, while the potential gain could be avoiding another COVID-19 spike altogether.

"If we could arrange to give everyone vitamin D, and it failed to protect them, so what? The risk from not acting is much greater than the risk from acting," Downing says, adding: "If you caught the COVID19 virus right now, having a good vitamin D status (from already having taken a supplement) would

Reduce your risk of the disease becoming severe by 90%

Reduce your risk of dying by 96%

This is not 'proven' or 'evidence-based' until we have done controlled trials comparing it to placebo … But the data, already strong, has been pouring in since the start of the pandemic."