A video has flooded Facebook claiming that 62% of people given an mRNA vaccine for COVID-19 have developed blood clots. However, experts told Reuters there is no evidence of this.
The clip was posted on July 7 and has been viewed 142,000 times (here , here). It shows a Canadian going by the name of "Dr Charles Hoffe" who says that blood clots caused by mRNA vaccines like Pfizer/BioNTech and Moderna are microscopic and can only be detected through a D-dimer blood test.
Public health experts at the Meedan Health Desk (here) explain that D-dimer is a blood protein released when a blood clot begins to dissolve or break down. When the D-dimer level is high, it can be because of a clot, but there are many other possible causes including pregnancy, cigarette smoking, inflammation, and advanced age (here).
In his video, Hoffe claims to have carried out D-dimer tests on people who received mRNA COVID-19 vaccines in the previous seven days. “I’m still trying to accumulate more information but, on the ones I have so far, 62% of them have evidence of clotting, which means that these blood clots are not rare,” Hoffe said. He added that the clots would lead to permanent cell damage in the heart and lungs.
Scientists have found a possible link between AstraZeneca and Johnson & Johnson COVID-19 vaccines and blood clots, but the risk for most people is low.
Reuters asked if Hoffe had any printed evidence to support his claims, but he said the results were preliminary and currently unpublished.
“I have realised that I need to publish it, even though the numbers of subjects that I was planning to have in my study are far smaller than my original intention,” Hoffe wrote in an email.
He said his research has been prevented by a fire that destroyed his medical practice. Hoffe is from the western Canadian town of Lytton (here , here , here) which suffered forest fires in July this year (here , here).
Tom Wingfield, a senior clinical lecturer at the Liverpool School of Tropical Medicine (here), told Reuters that he disagrees with Hoffe’s conclusions.
“If the D-dimer test is raised, this does not mean that that person has had a blood clot but, rather, further investigations such as a scan of the chest or leg may be required, depending on their symptoms,” he explained in an email.
Wingfield said a raised D-dimer can be caused by many factors and that the test is not done routinely after vaccination. Experts also told the AFP news agency that elevated D-dimer levels are not proof of blood clots (here).
Current research has not shown a link between mRNA COVID-19 vaccines and blood clots (here).
Wingfield said that blood clots with low platelets, including blood clots in the brain, occur at an estimated rate of 5 to 16 cases per million people annually. Reports by Britain’s Medicines and Healthcare products Regulatory Agency (MHRA) suggest that after the first dose of the AstraZeneca vaccine, the incidence rate stood at 14.9 events per million, and 1.8 per million after the second. (here , or here).
Wingfield concluded: “I strongly encourage those eligible to come forward to get this life-saving vaccine and advocate for more equitable roll-out of Covid-19 vaccines to people and communities around the world.”
False. Experts told Reuters that there is no evidence for mRNA vaccines being linked to blood clots and that methods used by Dr Charles Hoffe are unreliable.
This article was produced by the Reuters Fact Check team. Read more about our fact-checking work here .
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