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Rare blood clots up to 10 times more likely from COVID-19 infection than from Johnson & Johnson vaccine, report says

The chief of neurology at Lifespan Corporation says blood clots aren’t the only long-term effects she has seen in patients who have had COVID-19.

The COVID-19 vaccine developed by the Janssen Pharmaceutical Companies of Johnson & Johnson, is at Rhode Island Hospital.Jonathan Wiggs/Globe Staff

PROVIDENCE — The same rare blood clot condition connected to the Johnson & Johnson COVID-19 vaccine is more of a risk following a COVID-19 infection, according to a newly released report.

The American Heart Association and the American Stroke Association’s Stroke Council Leadership released the report Friday, which examines the symptoms and treatment options for cerebral venous sinus thrombosis, which are blood clots in the brain’s veins.

Although rare in both scenarios, Dr. Karen L. Furie, a lead author of the report and chief of neurology at Lifespan Corporation, says the risk of developing the blood clots is eight to 10 times higher following a COVID-19 infection than it is after receiving the Johnson & Johnson vaccine.


Just last week, Rhode Island state health officials accepted recommendations from the Centers for Disease Control and Prevention and the US Food and Drug Administration to lift the pause on administering the Johnson & Johnson COVID-19 vaccine.

Dr. Karen L. Furie chair of the department of neurology at The Warren Alpert Medical School of Brown University, and chief of neurology at Rhode Island Hospital, The Miriam Hospital and Bradley Hospital in Providence, Rhode Island. Bill Murphy

Cerebral venous sinus thrombosis, or CVST, is similar to what happens in most strokes, but in combination with thrombocytopenia, which is a low blood platelet count. Together, CVST and thrombocytopenia is called thrombosis-thrombocytopenia syndrome, or TTS. And when TTS is linked to receiving a COVID-19 vaccine, it’s called vaccine-induced immune thrombotic thrombocytopenia, or VITT.

“COVID-19 infection is a significant risk factor for CVST,” said Furie, who is also the chair of the department of neurology at the Warren Alpert Medical School of Brown University. “The public can be reassured by the CDC’s and FDA’s investigation and these statistics — the likelihood of developing CVST after a COVID-19 vaccine is extremely low.”

Speaking on behalf of the Council, she said, “We urge all adults to receive any of the approved COVID-19 vaccines.”

The data in the report was based on a preliminary analysis of US data throughout the pandemic, but before April 15, 2021. It included data from 59 health care organizations, totaling 81 patients, more than 98 percent of whom were in the US.


Furie said that while CVST is “extremely rare,” further research and investigation is necessary as the pandemic continues. She said data and robust research on the people who did not develop blood clots after the vaccine is needed as well, to fully understand “the molecular and cellular mechanisms underlying CVST related to COVID-19 infection or after vaccination.”

She said the blood clots aren’t the only long-term effects that she has seen in patients who have previously been diagnosed with COVID-19.

“A significant proportion of patients go on to subsequently complain of new problems in many organ systems, but predominantly around neurological or neuropsychiatric issues,” she told the Globe.

She said the National Institutes of Health is funding a project to look at the long-haul side effects of COVID-19, which will include brain imaging and blood biomarkers that might help identify individuals who are at risk for developing complications.

“I would say that we’re only a year and a half into this pandemic in the US and we’re still learning things as we go,” said Furie. “But I expect research in this area to go on for the next several years.”

Alexa Gagosz can be reached at alexa.gagosz@globe.com. Follow her on Twitter @alexagagosz and on Instagram @AlexaGagosz.