In addition to discussing the benefits of vitamin D supplementation in people with a vitamin D deficiency, this study also points to possible (smaller) effects of supplementation in people whose vitamin D level is sufficient according to current standards. This finding is important because those standards are largely based on the need for vitamin D for bone health, as the needs for immune function support are not yet known.
If vitamin D reduces the incidence of COVID-19, it is tempting to see if it can also reduce COVID-19 contamination. After all, vitamin D boosts immunity, so it can be expected to reduce COVID-19 infection and transmission. In addition, Vitamin D also affects zinc metabolism, which reduces the replication of coronaviruses.
This study provides food for thought and especially urges researchers to quickly look further into the possible beneficial effects of different doses of vitamin D, because that would be an inexpensive way to influence the number of positive test results.