There has been conflicting data concerning Moderna’s COVID vaccine. But a Danish study published in the British Medical Journal this week showed data that found Moderna’s vaccine is more likely than Pfizer’s vaccine to cause inflammation of the heart muscle.
Reuters reported that this study showed that Moderna is up to four times more likely than Pfizer to cause myocarditis or myopericarditis (heart inflammation).
This study comes after Sweden and Finland halted the Moderna vaccine due to these possible cardiovascular side effects, as CNBC reported in October.
About 4.9 million individuals in Denmark aged 12 and older, which is about 85 percent of population, participated in this study, according to Reuters.
“Vaccination with mRNA-1273 (Moderna’s vaccine) was associated with a significantly increased risk of myocarditis or myopericarditis in the Danish population,” the study said.
The Danish study found only 1 case per 71,400 vaccinated with Pfizer-BioNTech and 1 case per 23,800 vaccinated with Moderna. Most of the cases had been mild, the study concluded, as Reuters reported.
“In general, the rate of myocarditis or myopericarditis was about threefold to fourfold higher for mRNA-1273 (Moderna) vaccination than that for BNT162b2 (Pfizer-BioNTech) vaccination,” the study found.
Denmark is not alone in this study, however. Other countries and researchers have been looking into the side effects of the vaccines and COVID itself.
In Israel and the United States, studies were also conducted that showed an increased risk of cardiovascular side effects from the mRNA-vaccines. Moderna seems to have the highest risk, though, of all the mRNA vaccines.
In the U.K., another study was recently published that looked at the cardiovascular side effects of both the vaccines and the COVID-19 itself.
The study looked at 38 million people over the age of 16 in the U.K., and tracked the occurrence of cardiovascular issues within 28 days of either a vaccination or a positive COVID-19 test.
The study concluded that the “extra cases of myocarditis were between 1 and 10 per million persons in the month following vaccination, compared with 40 such events per million after infection with SARS-CoV-2,” NDTV News reported.
Scientists all over the world are still researching the side effects of the vaccines to fully understand the risks, even though the vaccines have already been widely rolled out all over the world.
“We know the Covid-19 vaccines are highly effective at reducing risks of severe outcomes. However, it is important that we know about and identify the risks of these rare conditions from vaccines as well, to ensure that clinicians know what to look for, aid earlier diagnosis, and inform clinical decision-making,” said Julia Hippisley-Cox, a professor of clinical epidemiology and general practice at Oxford, according to NDTV News.
While the cardiovascular side effects from both COVID and the vaccines may be low, they are still significant enough that researchers continue to run studies to investigate the risks.
However, though the risks of the vaccines are being studied and clarified, Danish researchers also commented that these findings do not mean that the vaccine is altogether dangerous.
“Our findings do not generally overshadow the many benefits that come with being vaccinated,” Anders Hviid, the study’s author, said in a statement, as Reuters reported. “One must keep in mind that the alternative of getting an infection with COVID-19 probably also involves a risk of inflammation in the heart muscle.”