A healthcare worker holds syringes of Moderna and Pfizer vaccines for coronavirus disease (COVID-19) at a vaccination center in El Paso, Texas on May 6, 2021.
Jose Luis González | Reuters
Finland, Denmark and Sweden are restricting the use of Moderna’s Covid-19 vaccine in young people due to concerns about rare cardiovascular side effects.
Finland’s national health agency THL announced on Thursday that it would suspend the use of Moderna’s Covid vaccine in young men. All men aged 30 or younger would be offered the Pfizer BioNTech vaccine instead, THL said.
THL’s decision followed announcements by its Swedish and Danish colleagues on Wednesday that both would restrict the use of the Moderna vaccine in similar demographics.
In Sweden, the vaccine is discontinued in people born in 1991 or later, while in Denmark Moderna vaccination is on hold for anyone under the age of 18.
What is the problem?
The three countries’ decision to restrict the use of the Moderna vaccine is based on concerns that may be linked to cases of myocarditis, a disease in which the heart muscle becomes inflamed. All three health authorities cited an unpublished Nordic study that, according to Reuters, had been sent to the European Medicines Agency for evaluation.
In most cases, people with myocarditis recover without complications, but in some rarer and more severe cases, the heart can be damaged.
According to the Finnish THL, myocarditis was most likely to develop in younger men and boys after they received their second dose of the Moderna vaccine.
In a press conference on Thursday, Mika Salminen, director of health safety at THL, said the potential risks of the Moderna vaccine appeared to be higher for younger males.
“The instruction from THL is that the Moderna vaccine should not be given to men and boys under the age of 30 for the time being, and that the Pfizer vaccine should be used instead,” he said, according to local media reports.
Finland offers Covid-19 vaccinations for everyone over 12 years of age. Of the population eligible for vaccination in Finland, 84% received their first dose and 72% received two doses.
Sweden’s health authority, meanwhile, said data suggested cases of myocarditis and pericarditis – an inflammation of the outer lining of the heart – were more common in young people who were vaccinated, Reuters reported Wednesday.
A Moderna spokesman was not immediately available for comment when contacted by CNBC. The company told Reuters that these “are usually mild cases and people recover quickly after standard treatment and rest”.
“The risk of myocarditis is significantly increased for those who contract COVID-19, and vaccination is the best way to protect yourself from it,” the spokesman added.
Benefits vs. Risks
Despite the risks associated with vaccination for young men, THL’s Salminen said Thursday that it was still important for anyone eligible for two doses of a vaccine.
According to the U.S. Centers for Disease Control and Prevention, the known risks of Covid-19 and its potentially serious complications far outweigh the possibility of a rare side effect of vaccination. This includes the potential risk of developing myocarditis.
In August, a US study found that men between the ages of 12 and 17 – the population most likely to develop myocarditis – are six times more likely to get heart infections from Covid-19 infection than from vaccination against the virus .
After a second dose of vaccine, there were 67 cases of myocarditis per million men in this age group. After contracting the coronavirus, the rate of myocarditis in this age group rose to 450 cases per million, the study found.
Meanwhile, an investigation by Imperial College London in March found that half of patients hospitalized with severe cases of Covid had heart damage.
According to the US CDC, most post-vaccination myocarditis occurs after a second dose of the Pfizer BioNTech or Moderna vaccine in adolescent males and young adults. Symptoms – including chest pain or tightness, shortness of breath, and palpitations – usually appear within days of vaccination.