Vitamin A won’t save you from measles (but it might ruin your liver)

File under: Still not taking health advice from a lawyer

Apr 03, 2025

TL:DR:

➡️ Vitamin A will not prevent or cure measles

➡️ High doses of Vitamin A can be dangerous.

➡️ Vaccination is the best way to prevent measles.

With measles cases on the rise, you may have heard “rumors” from a certain lawyer that taking Vitamin A is an effective treatment for measles that can “dramatically reduce" deaths from the disease.

The truth?

As with many things from this particular source, it’s a tiny truth wrapped in a big, misleading claim.

First, let’s review some basic infectious disease epidemiology:

Host-Pathogen Interactions:

The outcome of almost any infection is a function of not only the pathogen itself, but an interaction of the “host”—the person being infected, and the infectious agent. A pathogen will have some “intrinsic” severity or pathogenicity depending on its biology. This is the difference between the severity of the common cold (mild) vs. smallpox (deadly). But how that translates into severity in a particular human body depends on things that affect the host’s immune response- including age, underlying health, nutritional status, co-infections, how well they sleep, etc.

Vitamin A deficiency weakens immune defenses, especially mucosal surfaces like the eyes, respiratory tract, and gut. So, when a malnourished child gets measles, the infection can be more severe: pneumonia, blindness, or even death.

This is why the World Health Organization and CDC recommend two doses of Vitamin A for children already infected with measles under a physician’s care—especially in low-resource settings where deficiency is common. It’s not a cure. It’s supportive care. And it works—if the child is Vitamin A deficient.

In well-nourished children (like most in the U.S. and other high-income countries), Vitamin A has no meaningful effect on measles outcomes. Vitamin A deficiency is exceedingly rare in higher-income countries, as most kids get enough of the vitamin through foods like eggs, milk, cheese, vegetables, fish, and meat, as well as breast milk and infant formula.

A stylized example of this type of host-pathogen interaction is shown here:

The figure illustrates the basic idea of an interaction—Vitamin A supplementation can reduce measles severity, but only for children who are Vitamin A deficient. In other words, the effect of Vitamin A on measles severity depends on the nutritional status of the child. The flat line shows that for well-nourished children, measles severity is the same whether they take Vitamin A or not.

Vitamin A's lack of effect in high-income countries was confirmed during a recent measles outbreak in Italy, where researchers found that supplementation did not reduce the length of hospitalization or complications.

Source: Lo Vecchio, Andrea MD, PhD; Cambriglia, Maria Donata MD; Bruzzese, Dario PhD^†; Guarino, Alfredo MD. Vitamin A in Children Hospitalized for Measles in a High-income Country. The Pediatric Infectious Disease Journal 40(8):p 723-729, August 2021

But with measles swirling around, you may be asking, “what’s the harm in trying to boost my child’s defenses with extra Vitamin A?”

⚠️ High doses of Vitamin A can be dangerous.

Vitamin A is a fat-soluble rather than water-soluble vitamin. This means that when we consume too much, it can accumulate in our bodies—we don’t just pee it out. At high doses, vitamin A can cause liver damage; nausea, dry, peeling skin; hair loss; and rarely seizures, and coma.

The danger of Vitamin A toxicity is no longer hypothetical. In Texas, a hospital recently reported multiple unvaccinated children with liver abnormalities after taking high doses of Vitamin A. This is a stark reminder that misleading information about “natural” remedies is not benign. Statements encouraging at home Vitamin A supplementation for measles in the US are directly harming real children.