The Swedish health agency on Wednesday (October 6) said the country is suspending the use of Moderna's COVID-19 vaccine for people born in 1991 and later.
That announcement came after reports of possible rare side effects among youths and young adults such as myocarditis, an inflammation of the heart muscle, which the Mayo Clinic says can include symptoms that resemble a heart attack.
In a statement, the health agency said the connection is especially clear when it comes to Moderna's vaccine Spikevax, especially after the second dose.
It added that the risk of being affected was very small.
The health agency now recommended the Comirnaty vaccine from Pfizer/Biontech instead.
Some 81,000 people born in 1991 or later had received a first Moderna shot.
They would not be getting a second jab.
Earlier this week the Swedish health agency said people aged 12-15 would only get the Pfizer/Biontech vaccine.
The European Medicines Agency approved the use of Comirnaty in May, while Spikevax was given the nod for children over 12 in July.