An audit of the U.S. Centers for Disease Control and Prevention (CDC) public databases published in Annals of Internal Medicine has found that nearly half of routinely updated federal health surveillance systems have stopped or delayed updates in 2025.

The lack of updates matters because gaps in data, particularly on vaccinations and respiratory disease infections, undermines doctors' and public health officials and ultimately the public's ability to be aware of and prepared for outbreaks of infectious diseases. More broadly, the lack of up-to-date information will affect public health policy and erode public trust.

Eighty-nine percent of the paused databases had pauses lasting more than six months.

Researchers from Vanderbilt University, University of North Carolina, Chapel Hill and Boston University School of Law reviewed the CDC's public data catalog to check for updates in late October 2025. They examined more than 1,300 listed databases, focusing on those that had previously been updated at least monthly.

Using each database's stated update schedule, they classified whether updates were current or paused.

Of 82 databases that had monthly updates, 44 (54 percent) were current and 38 (46 percent) had unexplained pauses. Eighty-nine percent of the paused databases had pauses lasting more than six months.

Eighty-seven percent of the paused databases involved vaccines and vaccination-related topics. A check on whether the paused databases had been updated by 2 December 2025 found that only one had been updated, though some CDC databases may have been updated since early December.

The failure to update federal databases that are important to protect Americans from infections and other diseases leaves health care leaders and providers without the information they need to offer guidance on ways to deliver care. Out-of-date information may reduce public trust in information from the CDC. Data regarding immunizations had the biggest gap, compromizing this important form of care.

The authors conclude that prolonged, unexplained pauses in federal health surveillance data risk weakening evidence-based decision-making and recommend minimum transparency standards, including clear status updates, reasons for delays and timelines for resuming data publication.

Two limitations are worth noting. The research only looked at databases that were updated monthly or more frequently, and the study was not designed to determine reasons for the pauses.

Without reliable data, the U.S. is not only flying blind in the face of emerging and re-emerging threats to human health and well-being but also is deprived of the data that have proven effective against emerging and infectious diseases.

In an editorial accompanying the study, the chief executive officer of the Infectious Disease Society of America, Jeanne Marrazzo, MD, MPH, noted that without reliable data, the U.S. is not only flying blind in the face of emerging and re-emerging threats to human health and well-being, but also is deprived of the data that have proven effective against emerging and infectious diseases.

“Ideally, the generation of community-based health interventions aimed at infectious diseases follows a virtuous cycle,” she writes. “A need is identified, typically through routine epidemiologic surveillance (for example, an uptick in emergency visits for influenza-like respiratory infections) or through the spontaneous appearance of an event of concern (a fatal case of foodborne listeriosis in a pregnant woman). These observations prompt action ranging from the deployment of existing medical countermeasures (vaccines, therapeutics, and monoclonal antibodies) or their urgent development, withdrawal of contaminated products, or mitigation of environmental threats.”

The study and a Summary for Patients are published in Annals of Internal Medicine.