Scientists and public health leaders are taking stock of the Trump administration's abrupt decision to pull down web pages, datasets and selected information from federal health websites.
Some of the pages on the Center for Disease Control and Prevention website that went offline last week have since reappeared.
The Atlas Tool, used by policymakers to track rates of infectious diseases such as HIV and STIs, disappeared but now is back. Pages that explained the Youth Risk Behavior Surveillance System, which monitors adolescent health, were gone but can now be seen again. And the CDC's data site, which was taken offline over the weekend, is back up with datasets available for download.
But there is uncertainty about what may be different.
"Across the country, folks like me are trying to catalogue what is missing and what has changed in terms of what's back up," says Dr. Megan Ranney, an emergency physician and dean of Yale University's School of Public Health.
Some of it is obvious, she says — broken links and pages that are no longer there. She's noticed how some pages have been scrubbed of certain words or categories of people. For example, pages on the CDC website that previously referred to "pregnant people" now refer to "pregnant women." But, she notes, researchers are systematically comparing archival data with the updated datasets that have been reposted online.
Meanwhile, other pages — including a tool that assesses social factors that make communities vulnerable in the event of a disaster — remain offline. In other cases, such as with the Youth Risk Behavior Surveillance System, pages appear to be restored, but key links to results are dead.
In response to a request for comment on the missing and altered content on its website, a CDC spokesperson wrote in an email: "All changes to the HHS website and HHS division websites are in accordance with President Trump's January 20 Executive Orders, Defending Women from Gender Ideology Extremism and Restoring Biological Truth to the Federal Government and Ending Radical And Wasteful Government DEI Programs And Preferencing. The Office of Personnel Management has provided initial guidance on both Executive Orders and HHS and divisions are acting accordingly to execute."
President Trump's executive orders on gender and diversity, equity and inclusion have prompted the purge that spanned many of the agencies overseen by the Department of Health and Human Services.
The move swept up many resources on the CDC website, ranging from data on adolescent health and infectious disease to clinical guidelines on reproductive care and HIV.
Still, the agency's entire website carries a caveat: "CDC's website is being modified to comply with President Trump's Executive Orders."
A fight to preserve vital datasets
Opposition to last week's changes erupted quickly from across the scientific and medical community.
"This is completely unprecedented," says Dr. Nirav R. Shah, a senior scholar at Stanford University and former commissioner of the New York State Department of Health. "We're actually dimming the lights on our ability to protect and preserve the health of all Americans."
As news spread late last week, so did an internet-wide effort among scientists, journalists and concerned citizens to archive reams of data and web pages. Some of the clinical guidelines, like those on reproductive health, are now being hosted by physician groups, including the American Congress of Obstetricians and Gynecologists.
A group at Harvard University is one of several efforts among academics to preserve the data and keep it accessible. Jonathan Gilmour, a data scientist at the Harvard T.H. Chan School of Public Health, helped organize a "datathon" to help preserve health data on Jan. 31. He says the efforts to preserve data started back in November 2024 but were not complete by Friday's purge.
"These federal websites are gigantic, and result in terabytes of data," he says. While they've succeeded in preserving certain tools and datasets, "We're not sure yet to what extent we've captured all the webpages that have disappeared," he says.
Meanwhile, Doctors for America, a progressive advocacy group representing physicians, filed a lawsuit against the federal health agencies in response to the "sudden unannounced removal" of web pages and datasets.
The lawsuit argues that doing so violates the Administrative Procedures Act and the Paperwork Reduction Act, according to James Hodge, director of the ASU Center for Public Health Law and Policy.
"Both of these arguments may have some merit, but also seem mere initial 'shots across the bow' related to the larger legal issues at play," he wrote in an email to NPR. Hodge anticipates broader legal challenges regarding the constitutionality of President Trump's executive orders and the public's First Amendment rights to accessing governmental information, among others.
CDC advisors demand explanations
Shah and others who sit on the CDC's Advisory Committee to the Director, have asked the acting CDC director, Susan Monarez, a Trump appointee, for an explanation of why the data was taken down and the plans to safeguard and restore access to it.
The committee members requested a written response by February 7, according to a copy of the letter reviewed by NPR. So far, Shah says, they have not heard back yet.
Dr. Perry Halkitis, dean of the Rutgers School of Public Health, says he was struck by the "haphazard" manner in which sites were scrubbed or pulled down.
"I think limits are being tested," he says. "The question is how much will be tolerated."
Halkitis now worries about the future of other critical databases maintained by the federal government, including the National Institutes of Health's PubMed, which houses millions of manuscripts related to biomedical literature.
"Those of us who do science with marginalized populations, we're going to have to piece it together from our own research somehow," says Halkitis, noting that he and his colleagues scrambled to download HIV data last week in anticipation that references to gender and race, both of which are key to understanding the epidemiology of the disease, might be removed.
Fallout will stymie public health
The loss of essential data on infectious disease outbreaks affects the American public, beyond certain populations that appear to be targeted, says Dr. Josh Barocas, an infectious disease physician and public health researcher at the University of Colorado School of Medicine.
"These data help us understand, as scientists and clinicians, where infectious diseases and outbreaks are, so even if you are not part of that group, it helps us keep you safe," he says.
The lack of communication about this data and information gap also disrupts the relationship between the CDC and its partners, Shah says.
"All of the work that happens between scientists, communities, the CDC and others takes decades to build up over trust, and trust is based on transparency. That trust has been violated," he says.
Irma Elo, a sociologist at the University of Pennsylvania, points out this data belongs to taxpayers — and it's incumbent on the federal government to maintain its integrity.
"The government should restore all the data that had been previously collected and make it available," says Elo, who is president of the Population Association of America, which protested the changes made by the Trump administration. She describes the federal statistical system, which collects population-level census and health data, as "the only independent source of data that we have."
"You cannot just replace it without having a huge influx of resources," she says, or without the expertise of statistical agencies that have collected and published these data for decades.
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