Over roughly the past year, a large number of federal health‑related datasets have been removed, frozen, or altered, especially at CDC and HHS. These aren’t all formally “abolished,” but for researchers they function as disappearing data because access, documentation, or ongoing collection has been cut off.
Below is a focused map of major healthcare datasets that have gone dark or been curtailed.
Big national health surveys
BRFSS – Behavioral Risk Factor Surveillance System (CDC)
Long‑running telephone survey tracking chronic disease, risk behaviors, and preventive care; widely used in public health and health‑services research.
In early 2025, data files for all years were briefly taken offline, reappearing without key documentation like questionnaires and codebooks, which are essential for rigorous analysis.
For a period, the BRFSS section on CDC’s site only showed “page not found,” raising concern about whether past and future waves would stay accessible.
YRBS/YRBSS – Youth Risk Behavior Surveillance System (CDC)
Tracks adolescent behaviors (smoking, alcohol and drug use, sexual behavior, diet, exercise, etc.) going back to 1990.
Was taken off the CDC website in January 2025; researchers received notice that the YRBS “has been removed” from public access.
Later restored only after legal and political pressure, with new disclaimers about “gender ideology”, and concerns that future data collection could be curtailed or reshaped.
PRAMS – Pregnancy Risk Assessment Monitoring System (CDC)
A key survey on maternal and infant health outcomes, linked to maternal mortality research.
CDC has restricted access and stopped collecting new data, effectively halting the time series and preventing analysis of recent trends in maternal and infant mortality.
HIV, STI, and infectious‑disease data
CDC AtlasPlus and HIV/STI/TB surveillance dashboards
AtlasPlus provided 15+ years of data on HIV, viral hepatitis, STDs, TB, and social determinants of health; HIV surveillance reports dating back to the early epidemic were also affected.
As of early 2025, AtlasPlus and several HIV data pages were taken down, returning “page not found,” and historic HIV surveillance reports were removed from public view.
HIV Nexus and related clinical resources
The “HIV Nexus: CDC Resources for Clinicians” site, along with “HIV Data” links, generated page‑not‑found errors in January 2025, effectively cutting off easy access to clinical guidance and surveillance data.
Broader infectious‑disease data
Advocacy groups and researchers documented removal of datasets on infectious diseases, LGBTQ+ care, and reproductive services, leading to a lawsuit by Doctors for America on February 4, 2025.
Equity‑relevant and environmental health indices
CDC Social Vulnerability Index (SVI)
Census‑tract–level index used for disaster planning, vaccination targeting, and health‑equity work.
Went offline or became inaccessible during the late‑January 2025 removals; in some cases data files or documentation were missing even when pages partially returned.
Area Health Resource Files (AHRF)
Comprehensive county‑level dataset on health professionals, facilities, and related socio‑economic indicators used in workforce and access‑to‑care research.
These files were among the dashboards taken offline or partially offline in early 2025.
Environmental Justice Index (EJI)
Census‑tract–level composite of environmental, social, and health factors to identify at‑risk communities.
Also listed as one of the indices taken down or disrupted in that January 31, 2025 wave of removals.
Gender, reproductive, and LGBTQ+ health data
Datasets with gender fields and LGBTQ+ measures (CDC/HHS/VA)
A study by Freilich and colleagues found that nearly 13% of CDC online datasets disappeared between Jan 21 and Feb 11, 2025, and many that remained were altered, often substituting “gender” with “sex” and removing some categories.
By March 2025, datasets with explicit gender information were most affected, particularly after an anti‑DEI directive aimed at removing public‑facing references to “gender ideology.”
Reproductive and fertility care data
The same analysis and subsequent legal actions highlight removed data covering reproductive, fertility, and LGBTQ+ care, which are crucial for understanding access to services and health outcomes in these populations.
“Paused” databases and silent alterations
A 2026 Washington Post piece summarizing this work notes that between January and March 2025, over 200 CDC datasets (about 13% of their online collection) were removed, with only some later restored and many others significantly modified without documentation.
Among regularly updated health databases that suddenly stopped updating between May and October of the previous year, 87% of those paused were vaccine‑related, suggesting targeted interruption of vaccination surveillance.
In a separate Lancet Digital Health analysis, nearly half (49%) of the examined health datasets across CDC, HHS, and VA showed significant unannounced modifications to structure or content; only 13% documented that changes had been made.
Scale of what’s gone missing
KFF’s early 2025 review counted multiple major surveys and dashboards (BRFSS, YRBS, HIV AtlasPlus, PRAMS, AHRF, SVI, EJI, and others) as offline or partially missing documentation in the immediate aftermath of January 31 removals.
Later estimates from journalists and advocates suggest that since Trump returned to office, over 3,000 public datasets and thousands of web pages, many related to public health and healthcare, have been removed or significantly changed from federal websites.