Abstract
Background
Measles is a major cause of childhood morbidity and mortality. Vitamin A deficiency is a recognized risk factor for severe measles infections. The World Health Organization (WHO) recommends administration of an oral dose of vitamin A (200,000 international units (IU), or 100,000 IU in infants) each day for two days to children with measles when they live in areas where vitamin A deficiency may be present.
Objectives
To determine whether vitamin A therapy, commenced after measles has been diagnosed, is beneficial in preventing mortality, pneumonia and other secondary complications in children.
Search strategy
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to March 2005), EMBASE (1980 to December 2004) and looked for unpublished studies.
Selection criteria
Only randomized controlled trials in which children with measles were given vitamin A or placebo along with standard treatment were considered.
Data collection and analysis
Studies were assessed independently by two authors. The analysis of dichotomous outcomes was done using the StatXact software and results expressed as relative risk (RR) with 95% confidence interval (CI). Subgroup analyses were carried out for dose, formulation, age, hospitalization and pneumonia‐specific mortality. Weighted mean differences (WMD) with 95% CI were calculated for continuous outcomes.
Main results
There was no significant reduction in the risk of mortality in the vitamin A group when all the studies were pooled using the random‐effects model (RR 0.70; 95% CI 0.42 to 1.15). Using two doses of vitamin A (200,000 IU) on consecutive days was associated with a reduction in the risk of mortality in children under the age of two years (RR 0.18; 95% CI 0.03 to 0.61) and a reduction in the risk of pneumonia‐specific mortality (RR 0.33; 95% CI 0.08 to 0.92). There was no evidence that vitamin A in a single dose was associated with a reduced risk of mortality among children with measles. There was a reduction in the incidence of croup (RR 0.53; 95% CI 0.29 to 0.89) but no significant reduction in the incidence of pneumonia (RR 0.92; 95% CI 0.69 to 1.22) or diarrhoea (RR 0.80; 95% CI 0.27 to 2.34) with two doses.
Authors' conclusions
Although we found no overall significant reduction in mortality with vitamin A therapy for children with measles there was evidence that two doses were associated with a reduced risk of mortality and pneumonia‐specific mortality in children under the age of two years. There were no trials that directly compared a single dose with two doses.
Plain language summary
Two megadoses of vitamin A lowers the risk of death from measles in hospitalized children under the age of two years, but not in all children with measles
Measles is caused by a virus and results in a high fever and rash. Possible complications include pneumonia. Measles is a major cause of death in children in developing countries and is particularly dangerous for children with a vitamin A deficiency. This review found that there was no significant reduction in mortality in children receiving vitamin when all the studies were pooled together. However, vitamin A megadoses (200,000 international units on each of two days) lowered the number of deaths from measles in hospitalized children who were under the age of two years. A single dose did not lower death rates.