Measles was considered eliminated in the U.S. in 2000, meaning that there was not continuous transmission of the virus in the country for 12 months or more. But 2025 marked a record year with the most measles cases reported since 1991. Less than four months into 2026, cases in the U.S. are already nearing last year’s toll.
At the same time, the nation’s measles elimination status remains under review as health entities use genome sequencing to better understand the state of transmission. The Pan American Health Organization has pushed verification to November 2026, from its initially planned mid-April review.
In an April 9 episode of the Public Health On Call podcast, William Moss, MD, MPH, a professor in Epidemiology and executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health, explains what’s at stake with the verification of the U.S.’s elimination status and why this resurgence of measles is so concerning for immunization writ large.
