A large real-world case-control study from Israel finds that the Pfizer Covid-19 vaccine triples the risk of heart inflammation known as myocarditis.
"Vaccination had a strong association with an increased risk of myocarditis," concluded the study authors.
Myocarditis was already an acknowledged known risk of the vaccinations, particularly in young people.
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The study also found the Pfizer vaccine caused a increased risk of lymphadenopathy [swelling or inflammation of lymph nodes], appendicitis, and herpes zoster infection.
CDC says the benefits of Covid-19 vaccine outweigh the known risks, and that there is no cause for concern.
The Biden administration is mandating the vaccine for all employees and contractors, even those who have better protection than the vaccines provide because they have natural immunity after recovering from Covid-19. More than 120 million Americans fit into that category, according to CDC.
An August 10 study in JAMA Cardiology urged caution in giving Covid-19 vaccine to certain high risk patients due to the vaccine link to a serious blood disorder: thrombocytopenia with thrombosis. "One of the devastating manifestations of this syndrome, termed vaccine-induced immune thrombotic thrombocytopenia (VITT), is cerebral venous sinus thrombosis (CVST)," say the study authors. The link involves the AstraZeneca/Oxford and Johnson & Johnson vaccines, according to the study. The AstraZeneca vaccine is not administered in the U.S. currently.
CDC countered the news by saying that myocarditis is far more common in young people who have Covid-19 than in their uninfected peers. However, scientists say most young people don't get symptomatic Covid-19.
Another August 10 study in the same journal confirms the previously identified Pfizer vaccine's myocarditis (heart inflammation) risk in young boys.