As people grow up and they encounter new germs, their immune system builds up ways to protect itself from getting sick. But what happens when a disease is so powerful that it can make your immune system forget how to defend itself, leaving you more vulnerable to illnesses like pneumonia or chickenpox? That’s what measles can do.
The phenomenon, called immune amnesia, can be a long-lasting side effect of getting measles. With no treatments for immune amnesia, individuals may face an increased risk of getting sick for at least two years, research shows.
Measles continues to spread throughout the United States, with at least 483 confirmed cases reported so far in 2025 and a recent case being found in Colorado. Experts like Michelle Barron, MD — a professor of infectious diseases in the University of Colorado Department of Medicine and the senior medical director of infection prevention and control for UCHealth — are raising concerns about this highly contagious disease and its potential impacts on people’s health.
We recently spoke with Barron about what people should know about measles and immune amnesia and ways to stay protected.
The following interview has been edited and condensed.