On Tuesday, November 10, 2026, a growing number of U.S. counties are falling below the 95 percent measles vaccination threshold.
The measles-mumps-rubella vaccine is highly effective, but childhood vaccination rates are dropping. A vaccination rate of 95 percent or higher is needed to control measles in a community, and a growing number of counties now see that level fall below the protective threshold. The number of children entering kindergarten with vaccine opt-outs has climbed steadily for at least a decade.