As the United States battles its largest measles outbreak since the disease was declared eradicated in 2000, a new study has found that public interest in vitamin A and cod liver oil surged sharply after influential figures promoted supplements as treatments for measles, raising fresh concerns about misinformation, self-medication and vaccine hesitancy.

Researchers analysing Google search behaviour across the US found that online searches linking vitamin A and measles jumped dramatically between late February and March 2025, coinciding with media statements that promoted vitamin A as a treatment during the outbreak. The findings come at a time when health officials are struggling to contain rising measles cases and growing public distrust of vaccines.

The study, published in JAMA Network Open, examined daily Google search trends from January 1 to June 1, 2025. Researchers used search data as a measure of public interest and compared it with media coverage and public statements made during the outbreak. Their analysis employed advanced statistical techniques, including Bayesian interrupted-time series modelling to determine whether media attention was associated with changes in public behaviour.

Searches for "vitamin A" and measles remained relatively low until February 25. The following day, interest climbed by 44 per cent before reaching its highest level on March 22. Searches connecting cod liver oil and measles also spiked, peaking on March 5. Researchers found that vitamin A-related searches were significantly higher than expected after media coverage began.

The timing was striking.

Several public figures publicly discussed vitamin A as a potential measles treatment. While the researchers focused primarily on government-linked media statements, they noted that other influential personalities, including podcaster Joe Rogan and vaccine critic Suzanne Humphries, also made comments that may have amplified public interest.

Vitamin A does play a recognised role in measles care under medical supervision. Doctors may prescribe it to children with severe measles because it can help reduce complications and support recovery. However, experts stress that it does not prevent infection and is not a substitute for vaccination. Excessive intake can also be dangerous.

That warning appears increasingly relevant. According to America’s Poison Centers, reports of vitamin A exposure increased by 38.7 per cent between January and March 2025. High doses of vitamin A can cause headaches, liver damage, blurred vision, nausea, and, in severe cases, serious toxicity.

Researchers cautioned that search data cannot prove people actually consumed vitamin A or cod liver oil after reading about them online. Yet the findings highlight how quickly health messages can influence public behaviour during emergencies.

Public health experts say the resurgence of measles calls for stronger vaccination campaigns and clearer science-based communication. In an era where social media posts can spread faster than official guidance, they argue that trusted health information may be as important as medical treatment itself in preventing future outbreaks.