Pennsylvania has given the Centers for Disease Control and Prevention a clear deadline: publicly recognise four measles-associated deaths or the state will pull its request for a federal Epi-Aid. That condition was set out in a letter sent Wednesday from Debra Bogen, Pennsylvania’s secretary of health, to CDC director Erica Schwartz.

Bogen framed the demand as a matter of transparency and operational effectiveness, writing, "The CDC’s choice not to publicly recognize the deaths undermines our response." She added, "For this reason, if CDC is unable to transparently and accurately communicate information about those measles-associated deaths, the Department will respectfully rescind our request for a CDC Epi-Aid."

The appeal marks a reversal for state health officials, who had earlier signalled they could manage the outbreak without federal help. That shift follows a sharp worsening of the epidemic in Pennsylvania: the state has confirmed 731 measles cases across 38 counties this year, and reported four measles-related deaths as of Tuesday.

The demand sits inside a larger clash between state leaders and the federal health apparatus. Robert F. Kennedy Jr., the US health secretary, has questioned whether the Pennsylvania fatalities were caused by measles or by other conditions, and he instructed the CDC not to include the state's reported deaths in the national measles mortality count last month. Public health experts called that instruction highly unusual and warned it could understate the threat posed by measles.

Separately, the CDC has begun to rely on mortality figures from the National Center for Health Statistics, a counting method officials say is better for tracking trends over time. Reports note the reason for that adjustment has not been clarified, leaving uncertainty about how short-term death counts will be reflected in national totals.

The dispute plays out as the United States confronts its largest measles resurgence in more than three decades, which officials attribute to increasing vaccine hesitancy. Political pressure is mounting: Senator Bill Cassidy, chair of the Senate health committee, blamed the Trump administration’s vaccine-skeptical stance for recent measles deaths in Pennsylvania.

The immediate outcome now hinges on whether the CDC will publicly recognise the four deaths and whether federal and state health agencies can agree on a path forward. The CDC and the Pennsylvania Department of Health did not immediately respond to requests for comment.