Nicolas Hulscher, an epidemiologist affiliated with the McCullough Foundation, briefly vanished from X search results on October 27 after sharing a report that claimed vaccines were the leading preventable risk factor for autism, sparking a new round of questions about free speech on Elon Musk’s platform.

The disappearance occurred in the late afternoon or early evening, according to multiple users who began flagging the issue shortly after Hulscher posted excerpts from the study.

At 5:49 pm, Hulscher appeared to acknowledge the development himself. “This is our study that appears to have resulted in a removal of my account from the search results,” he wrote in a response post.

The Dallas Express independently verified that Hulscher’s account and posts were not visible at 9:29 pm local time that same day.

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His post quoted an earlier thread introducing what he described as “The Most Comprehensive Analysis Ever Conducted on the Causes of Autism.” The 300-study review, attributed to the McCullough Foundation, asserted that “combination and early-timed routine childhood vaccination constitutes the most significant modifiable risk factor for ASD.” The study also listed other potential contributors, including parental age, premature delivery, and environmental toxicants.

Hulscher’s affiliation with the McCullough Foundation—a US-based medical research organization led by cardiologist Dr. Peter McCullough—has drawn increased public attention since both men appeared at a Children’s Health Defense event in Highland Park last month, where they discussed President Donald Trump’s recent remarks questioning Tylenol and childhood vaccine safety, DX reported.

In an email to The Dallas Express, Hulscher said he received no advance notice from X about the change to his account’s visibility. “I did not receive any notification from X regarding the removal of my account from search results. However, after intense public backlash, X restored my account’s visibility a few hours later,” he wrote.

He added that he believes the post about vaccines and autism triggered the incident.

“I do believe that my sharing of our landmark autism report resulted in this apparent censoring of my account. This is gravely worrisome as X is supposed to be the flagship social media site of ‘free speech.’ Nonetheless, their sudden reversal of the obvious shadowban eases some of these fears,” Hulscher said.

Hulscher confirmed that he and the McCullough Foundation had contacted X for clarification.

“We have already sought clarification from X and have not received an adequate response explaining what happened. Nonetheless, no further action is required since they have reinstated my account in search results,” Hulscher said.

X, formerly known as Twitter, did not respond to an emailed request for comment from The Dallas Express by publication time.

The episode has drawn comparisons to earlier controversies involving the platform’s handling of speech on politically or scientifically charged issues.

In December 2024, X users who criticized Elon Musk’s and Vivek Ramaswamy’s defense of the H-1B visa program alleged they lost verification badges or monetization access, reviving debate over whether the company’s stated commitment to open dialogue aligns with its actions, DX reported.

Hulscher, a Michigan native with a Master of Public Health degree in epidemiology from the University of Michigan, has published several papers examining potential vaccine-related injuries and complications. His most recent work, co-authored with McCullough, revisited long-disputed claims about the relationship between vaccination and neurodevelopmental disorders.

The co-authors described the report as a “major breakthrough through the iron grip of censorship imposed by the Bio-Pharmaceutical Complex on the issue of vaccination and autism.”