Sweden and Denmark have stopped the administration of Moderna’s COVID vaccines on young age groups over rising incidences of side effects, including myocarditis.
The Swedish health agency said it would pause the vaccine for people born in 1991 and later, as data pointed to an increase of myocarditis and pericarditis among youths and young adults who had been vaccinated, Reuters reported.
“The connection is especially clear when it comes to Moderna’s vaccine, ‘Spikevax,’ especially after the second dose,” the health agency said in a statement.
Earlier this week, the Swedish health agency said 12- to 15-year-olds would only get Pfizer’s COVID vaccine.
Denmark said that, while it was already using the Pfizer/BioNTech vaccine as the main option for 12- to 17-year-olds, it had decided to pause the Moderna vaccine for people under 18 as a “precautionary principle.”
READ ALSO: Bad news for those who took COVID vaccine, here is why
“In the preliminary data … there is a suspicion of an increased risk of heart inflammation, when vaccinated with Moderna,” the Danish Health Authority said in a statement.
The agency referred to data from a yet unpublished Nordic study, which will be sent to the European Medicines Agency (EMA) for further assessment once the data is finalized, the agency added.
Norway, which already recommends the Comirnaty vaccine for minors, reiterated Wednesday rare side effects could happen, particularly in boys and young men, and mainly after receiving a second dose.
The EMA approved the use of Comirnaty in May, while Spikevax was approved for use in children over 12 in July, U.S. News reported.
Myocarditis is inflammation of the heart muscle that can lead to cardiac arrhythmia and death. According to the National Organization for Rare Disorders, myocarditis can result from infections, but “more commonly the myocarditis is a result of the body’s immune reaction to the initial heart damage.”
Pericarditis is inflammation of the tissue surrounding the heart that can cause sharp chest pain and other symptoms.
According to the the Vaccine Adverse Event Reporting System, there have been 6,561 cases of myocarditis and pericarditis reported following COVID vaccines, with 5,874 cases attributed to Pfizer, 1,515 cases to Moderna and 161 cases to Johnson & Johnson’s COVID vaccine between Dec. 14, 2020 and Sept. 24, 2021.
Among 12- to 17-year-olds, there have been 617 reports of myocarditis and pericarditis, with 603 cases attributed to Pfizer’s vaccine.
On June 25, the U.S. Food and Drug Administration (FDA) added a warning to patient and provider fact sheets for both Pfizer and Moderna COVID vaccines suggesting an increased risk of myocarditis and pericarditis — particularly following the second dose and with onset of symptoms within a few days after vaccination.
The FDA’s update followed a June 23 meeting which included a review of information and discussion by the Advisory Committee on Immunization Practices — a committee within the Centers for Disease Control and Prevention (CDC) that provides advice and guidance on effective control of vaccine-preventable diseases.