The little-known database at the heart of Kennedy's vaccine conspiracy theory

Yahoo

30-04-2025

For as long as Robert F. Kennedy Jr. has falsely claimed that vaccines cause widespread harm — from autism to sudden death — he has pointed to the one source he says could immediately prove it.
In speeches, interviews and writings, Kennedy has repeatedly claimed that the evidence of a massive public health cover-up lies buried in a little-known database of medical records of some 12 million Americans: the Vaccine Safety Datalink, or VSD.
'For decades, the CDC has kept a tight grip on the Vaccine Safety Datalink, concealing vital vaccine safety information from the public,' Kennedy said in 2023.
Kennedy now oversees the Centers for Disease Control and Prevention — including the Vaccine Safety Datalink — and one of his first initiatives as health secretary was to launch his long-dreamed-of study using the VSD to investigate the link between childhood vaccines and autism. It's a theory that has already been disproven in dozens of studies, many using VSD data.
'We're going to be able to get into these databases and give answers to the American public,' Kennedy said last month. He told President Donald Trump at recent Cabinet meeting that he would reveal the cause of autism by September.
However, in recent weeks, Kennedy's anti-vaccine allies have begun casting doubt on this pledge, once again alleging a government conspiracy to block access to the truth.
Without evidence, anti-vaccine lawyer Aaron Siri and activist Del Bigtree have claimed on the internet show "The HighWire" that the CDC scattered the vaccine safety data after Kennedy took office, making it unavailable for Kennedy's team to examine. The goal, according to Siri, was to 'thwart the ability for the current administration to actually conduct a study in the VSD.'
It's a pattern that has echoed through the first months of the Trump administration: Onetime outsiders who had long asserted that the federal government was hiding the truth suddenly had access to all the government documents they could want — only to reveal that, perhaps, there were no nefarious secrets after all. The JFK assassination files exposed little about his killing that wasn't already known. The release of records in the Jeffrey Epstein sex trafficking case was a dud. Trump and Elon Musk's claims that millions of people over 100 were receiving Social Security quickly fell apart.
Now, it appears that anti-vaccine activists are similarly girding for the possibility that Kennedy's promises may fall short — and they're already laying the groundwork for someone to blame.
'We've been saying that database is where the answers are,' Bigtree, who was communications director for Kennedy's 2024 presidential campaign, said of the VSD on 'The HighWire' last week. 'You could do the study in probably minutes with AI and computer learning and everything that's possible. Then the moment before Bobby gets in there to be able to do that study, what did they do? They obliterated it.'
It's not clear exactly what Bigtree and Siri meant; neither responded to requests for comment. Kennedy also didn't respond. A spokesperson for the Department of Health and Human Services initially said he would 'look into it,' but did not respond to further requests for comment. A CDC spokesperson confirmed that nothing about the stewardship of VSD data had changed in the last year.
There's one thing that Bigtree and Siri have right: The data in the VSD is not actually housed at the CDC — but that's not a recent change.
The VSD is a collaboration between a small team at the CDC's Immunization Safety Office and 11 private health care organizations. Since the 1990s, it's been used to monitor vaccine safety and conduct studies of rare side effects.
'These studies that use the VSD are able to tell the difference between a condition that coincidentally happens after vaccination and a condition that may actually be the result of vaccination,' said Dr. Joshua Sharfstein, vice dean for public health practice at the Johns Hopkins Bloomberg School of Public Health.
The health care organizations used to send their anonymized medical data to the CDC each year for analysis, but since 2001, the organizations have kept the data on their own servers, to ensure it stays secure.
'Sometimes people have the image that if there's a vaccine safety study, there must be one giant database with all the information in it,' Sharfstein said. 'If you're not familiar with how distributed networks of data are designed and used in studies, then it can be confusing. Because there is no one big dataset. There is no single file that can just be sent or released.'
The conspiracy lore around the VSD began in the early aughts, around the time that Kennedy, then an environmental lawyer, was being introduced to the anti-vaccine movement.
At that point, the only groups with access to the VSD were the CDC and the participating health care organizations. The studies they produced relied on the data they collected, including from doctor and hospital visits, vaccinations, pharmacies and lab results.
Then in 2002, Rep. Dan Burton, R-Ind., who had a grandson he believed had been injured by vaccines, allied with several parent-led autism groups. Frustrated with anti-vaccine researchers' lack of access to data that might prove the link, Burton threatened to subpoena the VSD's patient records.
At a hearing on the topic, Rep. Henry Waxman, D-Calif., urged Burton not to do it.
'A subpoena could have the effect of driving HMOs from the program and destroying CDC's ability to scientifically test hypotheses relating to adverse events potentially associated with vaccines,' Waxman warned, referring to the health care organizations. (Burton and Waxman left Congress in the mid-2010s.)
Subpoenaing millions of medical records 'would have been a profound invasion of privacy,' said Johns Hopkins' Sharfstein.
The CDC offered a solution: It would work with the participating health organizations to get independent researchers access to the data. Among the earliest beneficiaries — with the help of former Rep. Dave Weldon, R-Fla., the recently withdrawn CDC director nominee — were the anti-vaccine researchers Mark and David Geier, a father-son pair who baselessly theorized that autism was the result of an interaction between a preservative in vaccines and testosterone.
(Mark Geier died this year in Florida, over a decade after being stripped of his medical license in several states, partly for improperly treating autistic children with hormone blockers. David Geier, who was disciplined by the Maryland Board of Physicians for practicing medicine without a license in 2012, was hired at HHS this year as a senior data analyst to reanalyze vaccine safety data under Kennedy, according to two sources familiar with the plan.)
The Geiers' work with VSD data was marked by alleged ethical breaches. In 2003 and 2004, the Geiers visited the CDC's Maryland data center to access VSD data for a study looking at whether the diphtheria, tetanus and pertussis vaccine increased risks for harmful side effects.
Instead, according to a letter of complaint from one of the health care groups, Kaiser Permanente Northern California, the Geiers violated protocol and began comparing rates of autism in children who received vaccines with different amounts of a preservative. Further, Kaiser Permanente said the Geiers tried to merge datasets in a way that would have risked patients' confidentiality, then tried to remove files from the datacenter. Subsequently, Kaiser Permanente suspended the Geiers' access to the VSD.
The Geiers denied the accusations and published their findings in journals known more for conspiracy theories than rigorous science. At an Institute of Medicine panel in 2004, Mark Geier claimed the VSD data they analyzed showed that vaccines were linked to autism. Their published papers have been widely criticized by scientists and their findings never replicated or supported by mainstream research.
In 2006, they were approved for another study using VSD data, and again, stopped after violating protocol, according to lawyers representing the government in a set of test cases known as the Omnibus Autism Proceedings. Lawyers representing the parents of autistic children — for whom the Geiers had been providing research — suggested in legal filings that the Geiers had been unfairly banned at the whims of CDC.
For the Geiers, the experience was one of oppression. At anti-vaccine conferences, they presented PowerPoints alleging that the CDC had 'restricted' their access to data and 'attacked' their findings.
At the same conferences, Kennedy, who has consistently praised the Geiers, told a similar story.
'Oh, they've hidden it, and they won't let anybody in it, except their own guys who cherry-pick and design these fabricated studies and change the protocols constantly to try to use it to defend vaccines,' Kennedy said in a 2017 keynote at AutismOne, an anti-vaccine conference for parents of autistic children where the Geiers also presented. 'It's being used instead to craft these fabricated, fraudulent studies,' he said, 'to fool the public about vaccine safety.'
That same year, as Trump considered chairing a committee to review vaccine safety, Kennedy and a group of anti-vaccine activists met with Francis Collins, then the director of the National Institutes of Health, to ask him to 'open up' the VSD to scientists who would 'investigate whether vaccines are associated with the epidemic of health disorders plaguing our children today.'
In a letter following the meeting, Collins, who resigned from the NIH last month, told Kennedy that because of privacy concerns, access was limited to researchers who made formal requests and met certain criteria. Further, Collins said the kind of study Kennedy had suggested would be difficult because the sample population of unvaccinated children in the VSD — already just a fraction of the U.S. population — would be too small.
Now, with Kennedy at the helm of HHS and Geier working for him, there are no roadblocks left.
This article was originally published on NBCNews.com