US measles outbreak in 2025 fuels dangerous vitamin A supplement trend

Measles cases in the US reached 2,288 in 2025—the highest number since 1991. Nearly all infections occurred in people who were unvaccinated or only partially protected. At the same time, online searches for unproven treatments like vitamin A and cod liver oil spiked sharply after public discussions about their use. Between January and March 2025, poison control centres saw a 38.7% rise in reports of children exposed to vitamin A. The increase followed claims that the supplement could help with measles, despite no evidence supporting its use as a preventive measure. While vitamin A deficiency can worsen measles symptoms, such deficiencies are uncommon in the US.

Search interest in vitamin A hit its highest point on March 22, 2025, with a relative volume of 100%. Cod liver oil, another supplement promoted in discussions, saw its peak search volume of 52.6% on March 5. Overall, searches for vitamin A were 7.5 percentage points above expected levels, while cod liver oil queries exceeded projections by 1.3 percentage points. Medical professionals warn that incorrect vitamin A dosing can lead to serious health risks. Short-term effects include nausea and vomiting, while long-term consequences may involve bone thinning and liver damage. The supplement is only recommended under strict medical supervision for measles recovery—not as a replacement for vaccination.

The surge in measles cases coincided with a rise in unproven supplement searches and accidental vitamin A exposures. Health officials continue to stress that vaccination remains the most effective way to prevent infection. Without proper medical guidance, self-administered treatments pose unnecessary risks.