(CNN) — About a year ago, doctors began to notice that COVID-19 patients were coming to emergency rooms with strokes, complaining that blood clots were clogging dialysis machines and other equipment used to keep patients alive. coronavirus patients.
Frantic specialists in the intensive care unit reported “dramatic” blood clots in the heart, liver and other organs. Autopsies of coronavirus victims in New Orleans showed their lungs were clogged with clots.
Some young, apparently healthy patients suffered from massive strokes caused by Covid-19.
“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 have been doing this for a quarter of a century. I’ve never seen these levels of blood clots. “
Spyropoulos and his colleagues have conducted a series of studies showing that treating Covid-19 patients with blood thinners can dramatically reduce or even prevent these clots. And getting vaccinated against covid-19 can completely prevent them by avoiding infection in the first place.
So they feel that it is ironic that fears about a type of blood clot that is much, much, rarer, can now scare people, so much that they do not want to be vaccinated.
Last week, the U.S. Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) recommended pausing the distribution of the Johnson & Johnson’s coronavirus vaccine as experts investigate whether it can cause blood clots and, if so, what to do about it.
The European Medicines Agency said Tuesday that it had found a possible link, but said the overall benefits of the vaccine outweigh the risks. For use in the European Union, the agency said the vaccine must include a warning about “unusual blood clots with low platelets” as “very rare side effects.”
The CDC 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 both 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. Blood clots are estimated to kill about 100,000 people each year. The most common clots are those 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 surgeries, accidents, cancer treatments and even sitting for too long, said Dr. Mark Crowther, a hematologist and thrombosis expert at the American Society of Hematology.
“There are some minor risk factors, for example, air travel 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 the coronavirus greatly increases this risk.
“The vaccine, without a doubt, dramatically reduces the risk of any of the blood clots associated with COVID-19,” Crowther said.
The underlying cellular mechanism that may be involved in blood clots related to the Johnson & Johnson vaccine in the United States and the AstraZeneca vaccine in the United Kingdom and Europe is extremely rare and appears to involve a poorly understood immune response.
“The chances of getting what we call immune thrombotic thrombocytopenia caused by vaccines or VITT [por sus siglas en inglés] it’s one in a million, ”said Spyropoulos.
“The probability that you will be hospitalized with covid-19 is approximately 1 in 100 for the adult population. The probability of having a blood clot once you are hospitalized is likely 1 in 5 or 1 in 6 ”. That risk increases to 1 in 3 for people in an intensive care unit (ICU), Spyropoulos said.
“The benefits of any vaccine far outweigh the risks. Period, ”he said.
“This complication of the vaccine is extremely rare. Certainly more people are going to die from firearms in the United States than from these complications, ”agreed Crowther.
Many common blood clots go unnoticed, something the CDC wants to change. CDC is participating in an awareness campaign about blood clots that, if left untreated, can cause minor strokes or pulmonary embolisms that damage the lungs.
The rare blood clots associated with vaccines are an obvious clot type as they block the veins leading out of the brain and cause severe headaches or severe abdominal pain.
However, these develop slowly, allowing people the opportunity to receive the appropriate treatment if they seek it in time.
Now reports are beginning to appear in the media about people suffering from common blood clots after being vaccinated. These are unlikely to be caused by the vaccine, but it’s hard to tell the difference for people who aren’t trained in medicine, Crowther said.
Getting vaccinated, especially against covid-19, is a memorable event and it is natural for people who suffer from a health problem to associate it with the 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.
“The anticoagulant that is most likely to be used for many of these patients is exactly the one that would be used for ordinary blood clots,” Crowther said.
Options include pills like apixaban, sold as Eliquis, and rivaroxaban, sold as Xarelto. The American Society of Hematology also says that giving an antibody-based product called intravenous immunoglobulin can help restore a healthy balance of platelets.
“Any hospital in the United States would be well positioned to handle these blood clotting complications,” Crowther said.
The important thing at the moment is that doctors avoid the use of 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 going on with vaccines and blood clots.
Telltale signs of this rare reaction include not only blood clots, but also a low level of platelets that help the blood to clot.
That seems like a contradiction, but Spyropoulos says that what happens 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,” Spyropoulos said.