Scientists tested vitamin D for COVID and found an unexpected long COVID clue

A major clinical trial has delivered an unexpected twist in the search for ways to fight COVID-19 and its lingering effects. Researchers at Mass General Brigham found that taking high doses of vitamin D3 did not make COVID-19 infections less severe or reduce hospital visits. However, the study uncovered a subtle but intriguing signal suggesting that people who consistently took vitamin D supplements might be slightly less likely to develop long COVID symptoms weeks after infection.