As a measles outbreak spreads across the United States, doctors are now seeing a new and unexpected danger: children getting sick from taking too much vitamin A.

Confirmed measles cases in the US grew by 28% in a week to reach 483 this year, worsening a deadly outbreak that has already surpassed last year’s total.

The unidentified individual traveled to Washington DC, and may have spread the virus while visiting several locations.

A person with measles visited multiple high-traffic spots in Washington, DC while contagious — and now local health officials are racing to track down anyone who may have been exposed. DC Health confirmed the case on Tuesday,

The U.S. has already seen more measles cases in 2025 than it did in all of 2024. Here’s how to know if you need a vaccine or booster shot.