Nordic countries are restricting the use of Moderna’s Covid vaccine. Here’s why

A healthcare worker holds syringes with the Moderna and Pfizer vaccines against the coronavirus disease (COVID-19) at a vaccination centre, in El Paso, Texas, May 6, 2021.

Jose Luis Gonzalez | Reuters

Finland, Denmark and Sweden are limiting the use of Moderna‘s Covid-19 vaccine in young people over concerns around 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 PfizerBioNTech vaccine instead, THL said.

The decision by THL followed announcements from its Swedish and Danish counterparts on Wednesday that both would be restricting the use of the Moderna vaccine in similar demographics.

In Sweden, the use of the vaccine will be stopped in people born in 1991 or later, while Denmark is pausing the Moderna shot in everyone under the age of 18.

What’s the issue?

Finland offers Covid-19 vaccinations to everyone over the age of 12. Of the population eligible for vaccination in Finland, 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, Reuters reported Wednesday.

A spokesperson for Moderna was not immediately available for comment when contacted by CNBC. 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 added.

Benefits vs. risks

After a second dose of a vaccine, there were 67 cases of myocarditis per million males in that age group. After contracting the coronavirus, the rate of myocarditis in that age group shot up to 450 cases per million, the study found.

Meanwhile, research from Imperial College London in March found that half of patients hospitalized with severe cases of Covid were left with damage to their hearts.

According to the U.S. CDC, most cases of post-vaccination myocarditis occur after a second dose of the Pfizer-BioNTech or Moderna vaccine in male adolescents and young adults. Symptoms — which include pain or tightness in the chest, shortness of breath and heart palpitations — usually occur within days of vaccination.

(With inputs from CNBC)