A recent systematic review and meta-analysis of individual
participant data (n=10,933, aged 0 to 95 years), collected from high quality randomised controlled trials, investigated the overall
effect of vitamin D supplementation on risk of acute respiratory tract infection. The study, published in the BMJ
found that vitamin D supplementation reduced the risk of acute respiratory tract infection among all participants. Patients who were very
vitamin D deficient and those not receiving bolus doses experienced the most benefit.