Zinc supplementation for prevention of acute respiratory infections in infants: a randomized controlled trial.

OBJECTIVE To study the effect of 2 weeks of prophylactic zinc supplementation on incidence and duration of acute respiratory infections. DESIGN Randomized double blind controlled trial. SETTING Community based; urban resettlement area in North-East Delhi, India. PARTICIPANTS 272 children aged 6-11 months with acute respiratory infections. Children receiving zinc supplement within the past 3 months, severely malnourished, immuno-deficient, on steroid therapy, with severe illness requiring hospitalization, or children of families likely to migrate from the study area were excluded. INTERVENTION Placebo (syrup base) or zinc (20 mg/5 mL elemental zinc as zinc sulfate) orally given for a period of 2 weeks. MAIN OUTCOME MEASURE(S) Incidence, type and duration of acute respiratory infections, and adverse effects. RESULTS No effect on incidence of acute respiratory infections was noted. A decrease of 15% (0.78-0.94) in days and 12% (0.78-0.94) in duration of episode in acute respiratory infections was observed. Incidence of acute lower respiratory infections decreased by 62% (0.26-0.36) and the effect remained for full five months of follow up. There were no drop outs due to side effects. CONCLUSIONS Prophylactic zinc supplementation for two weeks may reduce the morbidity due to acute lower respiratory infections but not overall rate of acute respiratory infections in infants aged 6-11 months in similar populations.