We conducted a randomized, double-blind trial involving 189 children who were hospitalized at a regional center in South Africa because of measles complicated by pneumonia, diarrhea, or croup.
The children… were assigned to receive either vitamin A… or placebo…
Although clinically apparent vitamin A deficiency is rare in this population, the children’s serum retinol levels were markedly depressed… and 92 percent of them had hyporetinemia.
As compared with the placebo group, the children who received vitamin A recovered more rapidly from pneumonia… and diarrhea… had less croup… and spent fewer days in the hospital…
Of the 12 children who died, 10 were among those given placebo.
Treatment with vitamin A reduces morbidity and mortality in measles, and all children with severe measles should be given vitamin A supplements, whether or not they are thought to have a nutritional deficiency.
The idea that vitamin A may have a protective effect in measles was first suggested more than 50 years ago5 but was ignored until Barclay et al.,6 in a randomized clinical trial, found twice as many deaths in the control group… as among children given high doses of vitamin A.
That vitamin A should be of benefit in measles is biologically plausible. Measles depresses serum levels of vitamin A, and hyporetinemia is associated with increased mortality from the disease, particularly in children under two years of age.
In almost every known infectious disease, vitamin A deficiency is known to result in greater frequency, severity, or mortality.
Increased susceptibility to infection was one of the first features of nutritional vitamin A deficiency to be recognized, and even mild deficiency appears to be associated with an increased risk of pneumonia, diarrhea, and death in childhood.
According to Scrimshaw et al., “no nutritional deficiency in the animal kingdom is more consistently synergistic with infection than that of vitamin A.”
They list nearly 50 studies (including 8 in humans) of diseases of bacterial, viral, or protozoan origin in which vitamin A deficiency resulted in increased frequency, severity, or mortality.
In fact, vitamin A is sometimes referred to as the “anti- infective” vitamin.
[C]hildren under two years of age are at highest risk of an adverse outcome and derive the most benefit from vitamin A.