What to know about vitamin A's toxic risks after RFK Jr. promotes it for measles

Context: An unvaccinated Texas school-age child died of measles in February, marking the first reported measles death in the U.S. in a decade. A second death in New Mexico, also an unvaccinated person, is under investigation.

• Two doses of the measles, mumps, and rubella vaccine are 93% effective against measles.

State of play: Some unvaccinated child measles patients in Texas — the state with the most cases — have shown signs of vitamin A toxicity, including abnormal liver function, multiple outlets reported.

• Kennedy has said in multiple interviews that vitamin A and cod liver oil are effective measles treatments, per ABC News. He also blamed poor diets for severe measles cases.
• Kennedy also cast the measles outbreak as "not uncommon" in a Cabinet meeting, but the disease was declared eliminated from the U.S. in 2000.
• The Centers for Disease Control and Prevention updated its vitamin A recommendation "as part of supportive management" for children with severe measles.

Threat level: Taking too much vitamin A can cause headaches and increased intracranial pressure in both acute and chronic toxicity cases, according to the Merck Manual, a medical reference publication.

• Acute toxicity can also include nausea, vomiting, drowsiness, irritability and abdominal pain.
• Chronic toxicity causes changes in skin, hair and nails; generalized weakness; liver damage; and fetal birth defects.

Zoom in: Vitamin A deficiencies are uncommon in the U.S., according to the Mayo Clinic.

• However, supplements could be recommended for children who are diagnosed with measles.

What they're saying: The Council for Responsible Nutrition, a trade association for the dietary supplement industry, said in a statement that it is concerned about the inappropriate use of high-dose vitamin A, especially in children.

• "Vitamin A may be administered therapeutically to individuals who are already infected with measles, particularly in children with vitamin A deficiency, where it has been shown to help reduce the severity and complications of the disease," the statement said.

• "However, this use is a targeted, short-term medical intervention—not a preventive measure—and should only be done under the direction of a qualified healthcare professional."

By the numbers: As of March 27, a total of 483 confirmed measles cases were reported in 20 states, per the CDC.

• Of those, 97% of patients are unvaccinated or their vaccination status is unknown.
• 93% of confirmed cases were outbreak-associated, with five reported outbreaks.
• 42% of cases have been 5-19 year olds, and 33% have been children under 5.

Behind the scenes: Leaders at the CDC ordered staff not to release an expert assessment on measles, ProPublica reported.

• The report would have emphasized the importance of vaccination, as "risk of catching measles is high in areas near outbreaks where vaccination rates are lagging."

Go deeper: https://www.axios.com/2025/03/04/texas-measles-outbreak-cdc-rfk-jr-trump