Does Vitamin A Prevent Measles?

There are new cases of measles in my state. Can I give my baby vitamin A to protect her from the virus? How effective is vitamin A at preventing and treating measles?

—Anonymous

Let’s first state: the best protection against measles is the measles vaccine. If you are in an area with an active measles outbreak, it may make sense to vaccinate your child as early as six months.

Vitamin A does not prevent measles.

In developing countries, vitamin A has been shown to improve outcomes for children (especially under age 2) who are infected with measles. This may reflect a preexisting vitamin deficiency. In better-resourced environments (like the U.S., where vitamin A deficiency is far less common), there is little direct evidence for this treatment. One randomized trial in Italy showed that vitamin A supplementation had no impact on the clinical course of measles.

When a child is hospitalized for measles in the U.S., it is still common for doctors to consider a vitamin A supplement, because we have evidence of efficacy in some settings and there are limited downsides.

However, this should only be done under supervision of a doctor — the vitamins would be delivered directly, and the amounts closely monitored. Overdosing on vitamin A can be serious, possibly fatal. You should not give your child high doses of vitamin A (whether the vitamin itself or large amounts of foods like cod-liver oil) on your own, even if they have measles, and certainly not if they do not.