Researchers have identified two new but extremely rare side effects of the AstraZeneca COVID-19 vaccine, which are types of inflammation in the brain and spinal cord, in the largest vaccine safety study conducted to date. The Australian study, which included over 99 million people from Australia, Argentina, Canada, Denmark, Finland, France, New Zealand, and Scotland, confirmed the rarity of known vaccine complications, asserting that the benefits "still far outweigh the risks."
The researchers, who are part of a global vaccine data network, used information from participants after they received the Pfizer, Moderna, and AstraZeneca vaccines. According to the results published in the journal "Vaccine" on Friday, the study identified two new rare side effects, which are types of brain and spinal cord inflammation, as being associated with the AstraZeneca vaccine.
The study reported that "the incidence of these two types of inflammation is 0.78 cases per million and 1.82 cases per million, respectively, for each side effect." Alongside these two new side effects, the study confirmed with a high degree of accuracy the previously known associations between the Pfizer and Moderna vaccines and the rare side effects of myocarditis and pericarditis. It also reaffirmed known rare side effects of the AstraZeneca vaccine related to immune system attacks on nerves and venous sinus thrombosis.
