The US Centers for Disease Control and Prevention is working with the Council of State and Territorial Epidemiologists to develop a standardized case definition for measles deaths, the agency said Friday, as the outbreak grows across the country.
The CDC reported 3,471 confirmed measles cases in the United States as of September 17, up from 3,294 a week earlier, with no deaths recorded for 2026 in its national tally.
The Pennsylvania Department of Health earlier this week reported two more measles-associated deaths, both in unvaccinated individuals, bringing the state’s total outbreak-linked fatalities to four.
The CDC, however, has not included the deaths after the agency shifted to using mortality data from the National Center for Health Statistics for its national measles death count, moving away from its previous reliance on state health departments – a change that has drawn scrutiny.
The Pennsylvania health department on Thursday sought emergency support from the CDC to tackle its measles outbreak, on the condition that the agency recognize four measles-associated deaths reported by the state.
The CDC said it would update its reporting as more information becomes available and relevant reviews are completed.
On Wednesday, the US Senate health committee’s Republican chairman blamed the Trump administration’s approach to vaccines for recent measles deaths in Pennsylvania.
