No FDA admission about long-term blood clot risk for Covid-vaccinated

"FDA Admits Covid-Vaccinated at Risk of Blood Clots for Up to 15 Years," is the headline of a February 25, 2025 article by Slay News, which has previously spread health misinformation.

Screenshots of the article and replications of its text appeared across social media on Facebook, Instagram and X, including in French.

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Screenshot of Slay News article taken March 17, 2025

Vaccine misinformation is rampant online and has particularly affected conversations about the Covid-19 shots, which experts estimate saved millions of lives (archived here). The pandemic and the vaccine mandates imposed in many countries broadened the audience for skepticism.

Plummeting US immunization rates and outbreaks of once-vanquished childhood diseases such as the measles (archived here and here) have experts warning of a looming public health crisis.

There were reports of thrombosis linked to the AstraZeneca and Janssen vaccines released early in the coronavirus pandemic. This risk of blood clotting led to restrictions on these shots in several countries, including the United States and France, even as public health organizations such as the US Centers for Disease Control and Prevention (CDC) noted that cases were rare (archived here, here and here). 

But these were adenovirus vaccines, which use a different type of technology than the messenger RNA (mRNA) vaccines mentioned in the Slay News article (archived here).

Nicolas Gendron, a hematologist at the Georges Pompidou European Hospital in Paris, said the article is incorrect in claiming proof of decade plus-long risks associated with Covid-19 vaccines (archived here).

"Scientifically, to prove that patients are at risk for 15 years, they would have to be followed for at least 15 years," Gendron told AFP in a March 7 interview. "So, we cannot know if this risk is persistent, because vaccination started in 2021. In this case, we could only talk about a four-year risk."

Other purported evidence in the Slay News article also fails to prove any long-term risk of blood clots. 

Unrelated document

Advanced keyword searches surfaced no recent press releases mentioning "vaccines" or "blood clots" on the FDA's website.

One document cited by Slay News does come from the FDA, but it was advising on follow-up practices after human gene therapy treatments (archived here).

Text in the statement says it was published in January 2020, before any public roll-out of Covid-19 vaccines and as the first known Covid-19 cases were reported in the United States. The document discusses long-term observation after receiving gene therapy and states in a footnote that its guidance does not apply to vaccines.

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Screenshot of an FDA document with a footnote highlighted by AFP taken March 17, 2025

While false claims online have repeatedly confused the mRNA shots with gene therapies, these claims have been consistently debunked (archived here).

"Messenger RNA vaccines simply give cells information so that they temporarily code for something else," Gendron said. "This isn't gene therapy; pretending otherwise is just word manipulation."

Single-subject case report

Slay News also referenced a supposed "peer-reviewed study" published in a medical journal. However, the document is classified as a "case report" looking at one individual who died after receiving a vaccine, rather than a large-scale study observing multiple subjects.

One of the authors of the paper, Peter McCullough, has repeatedly spread misleading and false claims about Covid-19 vaccines fact-checked by AFP.

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Screenshot of a case report taken March 17, 2025

Gendron said a singular case was not enough to prove a hypothesis and that the scientific community prioritizes large, randomized trials to establish evidence.

"A 'case report' is when we report a case, but what we really like to know is if there have been others," he said.

Gendron also took issue with the conflation between the "acute pulmonary hemorrhage" mentioned in the case report and blood clots discussed in the Slay News article (archived here). A hemorrhage refers to blood loss from a damaged vessel, whereas blood clots are gel-like clumps forming inside the veins (archived here and here).

AFP has previously debunked misleading claims linking vaccines to clots found in corpses by embalmers, as well as allegations that the FDA admitted Pfizer's mRNA caused thrombosis -- which lacked context about the research.

As of March 18, 2025, the CDC continues to recommend that every person over the age of six months receive a Covid-19 vaccine and subsequent boosters (archived here).

Read more of AFP's reporting on vaccine misinformation here.