The effects of vitamin D supplementation in respiratory index of severity in children (risc) of hospitalized patients with community-acquired pneumonia: a double-blind randomized clinical trial  Rahmati et al., 2016[164]  Iran  Children hospitalized with pneumonia.  50,000 IU per day for 2 days  Lower duration of antibiotic use; other clinical characteristics were similar (fever, retractions, tachypnea, poor feeding, etc.).