Epidemiologist Professor Rickard Ljung of the Swedish Medical Products Agency and his colleagues further explored this in a recent study investigating health data on a total of some 23.1 million people from Denmark, Finland, Norway and Sweden from late December 2020 to early October 2021.
The team looked for incidences of myocarditis and pericarditis and, for each case, considered the subject’s sex, age and vaccination specifics.
They focussed in particular on cases where the inflammatory heart conditions developed within 28 days of either an initial or second vaccination shot.
By the end of the study period, the researchers reported, 81 percent of the subjects had been vaccinated.
Overall, the team identified 1,077 cases of myocarditis and 1,149 of pericarditis among their four study cohorts.