Escalating a political fight over two deaths in Pennsylvania, the Centers for Disease Control and Prevention said on Friday that it did not have any records to indicate “measles is the underlying cause” of any deaths in the country this year. The phrasing on its website, part of the agency’s weekly update to measles tallies, is the latest development in a heated disagreement between state and federal officials over whether the two deaths were a result of measles or merely coincided with the infection.

The C.D.C.’s update came even as the coroner for Lancaster County, where the deaths reportedly occurred, announced on Friday that a 6-week-old child in the county had died from measles. The child, who died last month, had a rare genetic disorder called Amish microcephaly, according to the coroner, Dr. Stephen Diamantoni. The Department of Health and Human Services directed a request for comment to a social media post by Health Secretary Robert F. Kennedy Jr.

Pennsylvania has been at the center of a rapidly escalating measles outbreak. Nearly 600 people have contracted the disease in the state, and nearly 100 have been hospitalized. Nationwide, the number of measles cases this year has topped 3,000, the highest in 35 years. Last week, Gov. Josh Shapiro of Pennsylvania, a Democrat, announced the two deaths in his state and said the federal government was partly to blame for hesitancy surrounding measles vaccinations.

In its measles update last week, the C.D.C. added an asterisked statement that the “available information does not establish” whether measles caused or contributed to the deaths in Pennsylvania. The agency’s update this week retains the asterisk under the death tally but makes no reference to Pennsylvania’s reports, saying its National Center for Health Statistics “does not currently have any death records” indicating measles as a cause of death.