Masks have a 100 year history of helping to stop respiratory infections. I'm taking vitamin D, but as the sun shining have other advantages as well (being outs

Masks have a 100 year history of helping to stop respiratory infections. I'm taking vitamin D, but as the sun shining have other advantages as well (being outside, not coughing that much because of the better weather), it's harder to decide whether taking extra vitamin D helps.