Finland paused the use of Moderna's COVID vaccine for younger males on Thursday (October 7).
It comes after reports of a rare cardiovascular side effect, myocarditis.
Finnish officials said they would instead give Pfizer's vaccine to men born in 1991 and later.
The country currently offers shots to people aged 12 and over.
Both Sweden and Denmark limited the use of Moderna on Wednesday (October 6) for all young adults and children.
They cited the same unpublished Nordic study as Finland.
Sweden's lead epidemiologist Anders Tegnell.
"It is, as I said, a very rare side effect we're talking about even if one has received the Moderna vaccine. Almost all the cases appear after a few weeks following vaccination and after one month one doesn't see this problem at all."
Another Scandinavian country - Norway - recommended this week that men under the age of 30 choose the Pfizer vaccine.
The Finnish health institute said the report would be published within a couple of weeks.
And that the data had been sent to the European Medicines Agency for further assessment.
The EMA found in July that such inflammatory heart conditions could occur in very rare cases following vaccination with Spikevax or the Pfizer jab in younger men after the second dose.
A Moderna spokesperson said late Wednesday it was aware of the decision made by Sweden and Denmark.
The drugmaker said the cases were typically mild and individuals usually recovered within a short time frame following standard treatment and rest.
Adding that the risk of myocarditis is substantially increased for those who get COVID, with vaccination the best way to protect against this.