Unexplained Pauses Hit Nearly Half of Monthly-Updated CDC Databases, Raising Transparency Concerns

Despite remaining publicly accessible, 38 CDC databases updated at least monthly were no longer current without notice as of October 28, 2025, potentially compromising the quality and transparency of public health decision-making.¹

Gaps in CDC Surveillance and Data Transparency

The authors of a study published today in Annals of Internal Medicine explained that real-time CDC surveillance data serve as “critical infrastructure” for research, policy development, clinical guidance, and trust across all areas of public health. Despite this, federal health databases experienced unprecedented removal and undocumented alteration in 2025. Specifically, several CDC databases were completely removed from public access in early 2025, and others were discontinued or experienced substantial delays in updates.

They identified several factors likely contributing to these pauses, including shifting governmental policies, personnel losses, and budget constraints affecting data collection and analytics. Vaccination tracking, in particular, is vulnerable because it requires ongoing coordination across federal, state, and health care system data sources. As a result, public health officials and policymakers may be unable to identify groups facing greater barriers to vaccination access and equity, limiting their abilities to address these disparities. These gaps also hinder efforts to counter misinformation and target outreach.

Because of this, the researchers conducted a study of CDC databases to identify those compromised by unexplained pauses. They aimed to evaluate how common these pauses were among frequently updated CDC databases, characterize their timing in relation to recent policy and federal workforce changes, and examine patterns in the topics of paused databases.

The researchers extracted metadata for all databases in the CDC’s public catalog on October 28, 2025, including titles, identifiers, issue dates, and updating periodicity. They identified databases with live webpages and, among these, frequently updated databases, defined as those with at least monthly updates or a title indicating such periodicity.

For each eligible database, the primary outcome was whether it had an unexplained pause as of October 28, 2025. The researchers categorized databases by topic into 4 groups: vaccination, infectious diseases, public health, and unrelated to health care or public health. They also documented whether databases focused on specific populations, categorized by age, pregnancy status, insurance type, and state-level reporting.

Unexplained Surveillance Pauses Disproportionately Affected Vaccination Databases

The researchers manually reviewed 1359 CDC databases, but their study focused on the 82 (6%) with at least monthly updates as of early 2025. As of October 28, 2025, 44 (54%) of these databases were current, while 38 (46%) had unexplained pauses. Among the latter, 34 had experienced a pause at least 6 months before the review date, whereas the remaining 4 were paused more recently.

Compared with none of the current databases, 33 paused databases (87%) reported vaccine-related information, with the most commonly reported types being influenza (n = 14), COVID-19 (n = 11), and respiratory syncytial virus (n = 6); 2 databases included all 3 vaccines. Of the 5 paused databases on other topics, 4 focused on respiratory diseases, including disease burden and nonvaccine prevention measures, while 1 addressed public health by tracking drug overdose deaths. In contrast, 38 of the 44 current databases (86%) addressed infectious disease topics other than vaccination, and 5 (11%) pertained to public health.

The researchers highlighted that compared with lower proportions among current databases, paused databases more commonly reported information on older adults (53%), younger adults (47%), and children (45%). In addition, a small number of paused databases reported information on pregnant women or stratified data by insurance type, whereas none of the current databases did so.

The paused databases were also commonly viewed and downloaded as of October 28, 2025. Lastly, when the researchers reexamined the 38 paused databases on December 2, 2025, only 1 had resumed updates.

Strengthening Federal Surveillance Through Transparency Standards

The researchers noted that unexplained pauses began predominantly in March and April 2025, shortly after President Donald Trump took office and Robert F. Kennedy Jr. was confirmed as HHS secretary. This period also coincided with many federal employees, particularly at the CDC, being fired or encouraged to retire.²

Consequently, they underscored that personnel losses, in addition to changing governmental policy directives, may have contributed to the paused databases.¹ Budget constraints may have also played a role, as the CDC was directed to reduce spending by approximately $2.9 billion, or about 35%, within a few weeks.

The researchers added that it is “concerning” that nearly 90% of the paused databases were related to vaccination surveillance, with additional gaps in respiratory disease monitoring.

“…the absence of any public notice of these pauses…can compromise the quality and transparency of decision-making about immunizations and other aspects of public health, even if the CDC later resumes updates,” the authors wrote.

Lastly, they acknowledged several limitations, including restricting their analysis to databases updated at least monthly, meaning they may have missed less frequently updated databases with unexplained pauses. The researchers also could not determine the reasons for individual pauses or the extent to which they resulted from policy choices, staffing shortfalls, or longer-planned program changes.

Despite these limitations, they expressed confidence in their findings and warned that weakened federal health surveillance poses a threat to clinical practice and public health decision-making.

“Federal databases should adopt minimum transparency standards, including displaying the current update status, with a rationale if paused, and next expected update with criteria for resumption,” the authors wrote. “Without such standards, unexplained pauses in surveillance risk undermine evidence-based medicine and public trust.”

References

1. Jacobs JW, Booth GS, Brewer NT, Freilich J. Unexplained pauses in Centers for Disease Control and Prevention surveillance: erosion of the public evidence base for health policy. Ann Intern Med. Published online January 26, 2026. doi:10.7326/ANNALS-25-04022
2. Valencia N, Goodman B, Tirrell M, et al. ’It’s a bloodbath’: massive wave of job cuts underway at US health agencies. CNN. April 2, 2025. Accessed January 26, 2026. https://www.cnn.com/2025/04/01/health/staff-cuts-at-federal-health-agencies-have-begun