Vitamin a toxicity: “Too much of a good thing”

Vitamin a toxicity: “Too much of a good thing” Fredric Gorin, Sarah Torres, and Pamela J. Lein discuss the implications of vitamin A supplementation during a recent measles outbreak in the US. They explain that a common misconception – that vitamin A supplementation can prevent the transmission of measles among unvaccinated individuals – can result in vitamin A toxicity. Vitamin A has garnered recent media attention as a preventative for measles, an interest driven in large part by reports in 2025 of the first major outbreak of measles in the United States in more than 20 years. Worldwide, measles cases are increasing and remain one of the most serious causes of childhood morbidity and mortality. Thus far, in 2025, 21% of children in the US younger than age five years were hospitalized with measles, with an overall mortality risk of one in three out of 1,000 people. This outbreak is largely a result of reduced measles vaccination coverage.