Abstract
BACKGROUND: Reduced vitamin A concentration increases the risk of blindness in children infected with the measles virus. Promoting vitamin A supplementation in children with measles contributes to the control of blindness in children, which is a high priority within the World Health Organization (WHO) VISION 2020 The Right to Sight Program. OBJECTIVES: To assess the efficacy of vitamin A in preventing blindness in children with measles without prior clinical features of vitamin A deficiency. SEARCH METHODS: We searched CENTRAL 2015, Issue 11, MEDLINE (1950 to December week 3, 2015), Embase (1974 to December 2015) and LILACS (1985 to December 2015). SELECTION CRITERIA: Randomised controlled trials (RCTs) assessing the efficacy of vitamin A in preventing blindness in well-nourished children diagnosed with measles but with no prior clinical features of vitamin A deficiency. DATA COLLECTION AND ANALYSIS: For the original review, two review authors independently assessed studies for eligibility and extracted data on reported outcomes. We contacted trial authors of the included studies for additional information on unpublished data. We included two RCTs which were clinically heterogenous. We presented the continuous outcomes reported as the mean difference (MD) with 95% confidence interval (CI) and dichotomous outcomes as risk ratio (RR) with 95% CI. Due to marked clinical heterogeneity we considered it inappropriate to perform a meta-analysis. MAIN RESULTS: For the first publication of this review, two RCTs involving 260 children with measles which compared vitamin A with placebo met the inclusion criteria. Neither study reported blindness or other ocular morbidities as end points. One trial of moderate quality suggested evidence of a significant increase in serum retinol levels in the vitamin A group one week after two doses of vitamin A (MD 9.45 µg/dL, 95% CI 2.19 to 16.71; 17 participants, moderate-quality evidence), but not six weeks after three doses of vitamin A (MD 2.56 µg/dL, 95% CI -5.28 to 10.40; 39 participants, moderate-quality evidence). There was no significant difference in weight gain six weeks (MD 0.39 kg, -0.04 to 0.82; 48 participants, moderate-quality evidence) and six months (MD 0.52 kg, 95% CI -0.08 to 1.12; 36 participants, moderate-quality evidence) after three doses of vitamin A.The second trial found no significant difference in serum retinol levels two weeks after a single dose of vitamin A (MD 2.67 µg/dL, 95% CI -0.29 to 5.63; 155 participants, moderate-quality evidence). Percentage of undernutrition between the two groups did not differ significantly at one week (RR 0.93, 95% CI 0.56 to 1.54, 145 participants) and two weeks (RR 0.82, 95% CI 0.52 to 1.29, 147 participants) after a single dose of vitamin A. No adverse event was reported in either study. We did not find any new RCTS for this second update. AUTHORS' CONCLUSIONS: We did not find any trials assessing whether or not vitamin A supplementation in children with measles prevents blindness, as neither study reported blindness or other ocular morbidities as end points.