More than 13.5 billion doses of COVID vaccines have been administered globally over the past three years.
The study published in the journal Vaccine found a small percentage
of the 99 million vaccinated individuals across eight countries analyzed experienced a higher risk of adverse events.
The report specifically looked at adverse events after administering the Pfizer, Moderna and AstraZeneca vaccines.
Researchers looked for 13 specific conditions. They found 190 cases of Guillain-Barré syndrome, which typically occurs after an infection but has been linked to some vaccines. They also found 69 cases of a type of blood clot that occurs in the brain.
Both mRNA vaccines from Pfizer and Moderna were associated with instances of myocarditis, inflammation of the heart muscle, which the study found consistently occurred more than was expected after the first, second and third doses.
COVID-19 itself can also cause side effects that affect the heart, including myocarditis.
While the observed side effects of the shots occurred more than anticipated, the number represents a tiny percentage of the millions of people overall who received the jabs, giving a clearer picture of the potential risk versus clinical benefit.
Researchers stressed that the “safety signals identified in this study should be evaluated in the context of their rarity, severity, and clinical relevance.”
Still, the study is likely to provoke additional largely partisan fighting over the vaccines. Researchers have noted the pandemic and associated partisanship has led to an increase in overall vaccine hesitancy among Americans, with troubling public health consequences.
