[colechristensen]

And also there's a difference between infection incidence, intensity, and duration, the evidence I've seen has been strongest in reducing intensity and duration. Also dosage might just be too low.

I've been feeling a little off lately with some respiratory symptoms and took 25,000 IU of Vitamin D, in people who are deficient (probably me lately) 400-1000 daily dose might not actually do enough to have an effect.

It's about time for a meta-meta analysis comparing the traits of the different sets of papers (N, dosage, deficiency status, time of year, duration/incidence/intensity, etc)