wsj | As U.S. health authorities expand use of the leading Covid-19 vaccines, researchers investigating heart-related risks linked to the shots are exploring several emerging theories, including one centered on the spike protein made in response to vaccination.
Researchers aren’t certain why the messenger RNA vaccines, one from Pfizer Inc. PFE -2.07% and partner BioNTech SE BNTX -5.83% and the other from Moderna Inc., MRNA -3.40% are likely causing the inflammatory heart conditions myocarditis and pericarditis in a small number of cases.
Some theories center on the type of spike protein that a person makes in response to the mRNA vaccines. The mRNA itself or other components of the vaccines, researchers say, could also be setting off certain inflammatory responses in some people.
One new theory under examination: improper injections of the vaccine directly into a vein, which sends the vaccine to heart muscle.
To find answers, some doctors and scientists are running tests in lab dishes and examining heart-tissue samples from people who developed myocarditis or pericarditis after getting vaccinated.
Myocarditis describes inflammation of the heart muscle, while pericarditis refers to inflammation of the sac surrounding the muscle.
Covid-19 itself can cause both conditions. They have also been reported in a smaller number of people who got an mRNA vaccine, most commonly in men under 30 years and adolescent males.
About 877 confirmed cases of myocarditis in vaccinated people under 30 years have been reported in the U.S., out of 86 million mRNA vaccine doses administered, according to the Centers for Disease Control and Prevention.
0 comments:
Post a Comment