Finland, Denmark and Sweden are limiting the use of Moderna’s Covid-19 vaccine in young people over concerns surrounding rare cardiovascular side effects.
Finland’s national health authority, THL, announced Thursday that it would pause the use of Moderna’s Covid vaccine in young men. All males aged 30 or younger would be offered the Pfizer vaccine instead, THL said.
THL’s decision followed announcements from its Swedish and Danish counterparts on Wednesday that both would be restricting the use of the Moderna vaccine in similar demographics for the same reasons.
Exact policies vary between the countries. In Sweden, the use of the vaccine will be stopped in people born in 1991 or later, while Denmark is pausing the use of the Moderna shot in everyone under the age of 18.
The decision the three countries have made to limit the use of the Moderna vaccine is based on evidence it could be linked to cases of myocarditis, a condition where the heart muscle becomes inflamed. All three health authorities cited an unpublished Nordic study which had been sent to the European Medicines Agency for assessment, Reuters reported.
In most cases, people with myocarditis recover without any complications, but in some rare and more severe cases, there can be damage to the heart.
Myocarditis was most likely to develop in younger men and boys after receiving their second dose of the Moderna vaccine, according to Finland’s THL.
Speaking at a coronavirus press briefing on Thursday, Mika Salminen, director of health security at THL, said the possible risks posed by the Moderna vaccine seemed to be higher for younger male individuals.
“THL’s instructions are that the Moderna vaccine should not be given to men and boys under the age of 30 for the time being, but that the Pfizer vaccine should be used instead,” he said.
Finland offers Covid-19 vaccinations to everyone over the age of 12. Of the population eligible for vaccination, thus far 84% have received their first dose and 72% have received two doses.
Sweden’s health body, meanwhile, said data suggested that instances of myocarditis and pericarditis — an inflammation of the outer lining of the heart — were higher among young people who had been immunized.
A spokesperson for Moderna was not immediately available for comment. The company told Reuters that these are “typically mild cases and individuals tend to recover within a short time following standard treatment and rest.”
“The risk of myocarditis is substantially increased for those who contract COVID-19, and vaccination is the best way to protect against this,” the spokesperson elaborated.
