“As an expert on blood clots, I can tell you that it is the most blood-clotting disease we’ve ever seen,” said Dr. Alex Spyropoulos, a professor at the Feinstein Institutes for Medical Research in New York.
“I’ve been doing this for a quarter of a century. I’ve never seen these levels of blood clots.”
So they feel it is ironic that fears about a much, much rarer type of blood clot can now scare people into not getting vaccinated.
Last week, the U.S. Centers for Disease Control and Prevention and the U.S. Food and Drug Administration recommended a pause in the distribution of Johnson & Johnson’s Janssen coronavirus vaccine while the Experts are investigating whether it can cause blood clots and, if so, what to do about it.
The European Medicines Agency said Tuesday it had found a possible link, but said the overall benefits of the vaccine outweigh the risks. For use in the EU, the agency said the vaccine must include a warning about “unusual blood clots with low platelets” as “very rare side effects.”
CDC’s Advisory Committee on Immunization Practices met last week to discuss the issue and decided to wait for more information after discussing the cases of six women who developed a very unusual type of blood clot after receiving the J&J vaccine, as well as other possible cases. They will meet again on Friday to present recommendations, which could include an additional warning to help vaccine recipients and doctors look for symptoms, or restrictions on who should get the J&J vaccine.
Whatever the risk from vaccines, experts agree that it is extremely low.
“You are as much at risk of being struck by lightning as you are of having one of these rare blood clots,” Spyropoulos told CNN.
Multiple risk factors
Blood clots in general are extremely common, affecting 900,000 Americans a year, according to the CDC. An estimated 100,000 people are killed each year. Especially common are clots in the brain. Approximately 795,000 people suffer strokes each year in the United States, according to the American Heart Association. The group estimates that between 10% and 15% of these are adults under the age of 45.
Common risk factors for blood clots include surgery, accidents, cancer treatments and even sitting too long, said Dr. Mark Crowther, a hematologist and thrombosis expert at the American Society of Hematology.
“There are some weak risk factors, for example, traveling by plane if you fly from Hawaii to Los Angeles,” Crowther told CNN. “Long car trips are risk factors,” added Crowther, chair of the department of medicine at McMaster University in Canada.
And being infected with coronavirus greatly increases this already common risk.
“The vaccine, without a doubt, dramatically reduces the risk of any of the blood clots associated with Covid,” Crowther said.
“The chances of getting what we call vaccine-induced immune thrombotic thrombocytopenia, or VITT, are one in a million,” said Spyropoulos.
“The chances that you will be hospitalized with Covid are about one in 100 for the adult population. The chances of having a blood clot once you are hospitalized are probably one in five or one in six.” That risk increases to 1 in 3 for people in the ICU, Spyropoulos said.
“The benefits of any vaccine far outweigh the risks, period,” he said.
“This vaccine complication is excruciatingly rare. Certainly, more people are going to die from firearms in the United States than from these complications,” concurred Crowther.
Rare blood clots associated with vaccines are one type that becomes obvious. They block the veins coming out of the brain and cause severe headaches or severe abdominal pain.
But they develop slowly, giving people the opportunity to receive the appropriate treatment, if they seek it in time.
Now, media reports are starting to appear about people suffering from more common blood clots after being vaccinated. They are unlikely to be caused by the vaccine, but it is difficult for people who are not trained in medicine to tell the difference, Crowther said.
Getting vaccinated, especially against Covid, is a memorable event, and it is natural for people who suffer from a health problem shortly after being vaccinated to associate it with that vaccine.
“Vaccine hesitancy is a real problem. There is no way the average person can understand the magnitude of the risks,” Crowther said. The results can be more deadly than blood clots.
The good news is that VITT is not difficult to treat, the experts agreed.
“Any hospital in the United States would be well positioned to handle these complications of blood clotting,” Crowther said.
The important thing at the moment is that doctors avoid using another common blood thinner known as heparin. Heparin itself can cause the same antibody reaction seen in VITT, and in fact, it was doctors familiar with the heparin-related reaction who noticed what might be happening with vaccines and blood clots.
Telltale signs of this rare reaction include not only blood clots, but also a low level of platelets, which help the blood to clot.
That seems like a contradiction, but Spyropoulos says that what is happening is an immune reaction in which the antibodies target platelets. “They form a complex that causes platelets to clump together,” he said.
Platelets disappear from the circulation as they stick together. “You see some kind of grime,” said Spyropoulos.