The U.S. Centers for Disease Control and Prevention (CDC) has updated its measles dashboard, but it has not yet included four reported deaths in Pennsylvania, where the outbreak is growing and cases are presenting in unfamiliar ways. Members of Congress have asked for an "immediate briefing" on the CDC's decision to change how measles deaths are reported, as cases are rising across the U.S. to levels not seen in decades. Recently, a potential measles exposure was reported in the neonatal intensive care unit (NICU) at Children’s Hospital of Philadelphia, raising concerns about the spread of the disease among vulnerable populations. Debra Houry, a former CDC chief medical officer, called the delay in reporting deaths "curious," even after the CDC updated its reporting process. It usually takes one to two days for the CDC to receive updated data from states after death investigations are completed. Houry noted that Pennsylvania had already concluded its investigation into the first two deaths, so the CDC should have those records now. Dr. John Goldman, an infectious disease specialist at the University of Pittsburgh Medical Center, said the outbreak is "accelerating," and doctors are now treating congenital measles — a rare condition where newborns contract the virus in the womb or at birth. "We’re literally seeing new forms of measles," Goldman said. "We don’t have a lot of information about what happens with it." Pennsylvania has reported 731 cases, but experts believe the number is likely an undercount. Measles is a highly contagious viral illness that can lead to severe complications and death. On average, one to three people out of every 1,000 infected will die, and one in five will require hospitalization. However, Houry said the current death and hospitalization rates in Pennsylvania are "definitely not proportional" to what is typically expected. She believes the official numbers are "very much an undercount," and under-testing can make contact tracing difficult, increasing the risk of further spread. The CDC collects data from states, including causes of death, but death certificates are issued at the state or local level, not the federal level. The agency is working with the Council of State and Territorial Epidemiologists to define what constitutes a measles death. Until a specific definition is created, the CDC relies on data from the National Center for Health Statistics (NCHS), which identifies measles as the underlying cause of death based on information submitted by states. CDC Director Erica Schwartz denied that deaths were being miscounted for political reasons, instead pointing to the process of defining what constitutes a measles death. She used an example of someone who dies from a car accident but also has a concurrent illness, such as COVID-19, to explain how deaths are categorized. However, Houry said such a scenario would not apply to measles deaths in Pennsylvania, as the state’s definition clearly excludes unrelated causes. Robert F. Kennedy Jr., the U.S. Secretary of Health and Human Services, has cast doubt on the reported deaths and reportedly instructed Schwartz not to include them in the CDC tally. During a speech at an anti-vaccine conference, Kennedy mentioned the outbreak briefly, asking for more attention on vaccine side effects, which are rare compared to the risks of measles. Pennsylvania has taken aggressive steps to combat the outbreak, setting up more than 100 pop-up clinics and requesting additional vaccination support from the CDC. The state’s health department has been praised for its rapid response, including quick turnaround times for testing and support for health systems. Dr. Goldman noted that the undercount of cases is not due to a lack of testing but rather people staying home when they are sick. Goldman, who hasn’t seen a measles case since 1992, said the outbreak has been a wake-up call. He fears the resurgence of measles may signal a broader decline in vaccination rates, which could lead to the re-emergence of other preventable diseases. "In a way, I think this is a warning," he said. "What worries me is measles is conceivably the canary in the coal mine."