Chicago – August 30, 2026
The share of American kindergartners considered susceptible to measles has increased by more than half since 2019, raising concerns about declining vaccination coverage and the risk of outbreaks.
Recent public-health data indicate that fewer children are entering kindergarten with documented protection against measles, primarily because fewer are receiving the recommended two doses of the measles, mumps and rubella (MMR) vaccine or because vaccination records are incomplete.
Measles is one of the most contagious infectious diseases and can spread rapidly in communities where vaccination coverage falls below levels needed to maintain herd immunity. Health officials generally recommend maintaining very high vaccination coverage to prevent sustained transmission.
The decline has occurred amid growing vaccine hesitancy, disruptions to routine healthcare during the COVID-19 pandemic and exemptions from school vaccination requirements in some states.
Public-health experts warn that increasing susceptibility among young children could make the United States more vulnerable to larger measles outbreaks, particularly when cases are introduced through international travel.
