In a press release issued in Denmark by the Danish Medicines Agency, media have been informed that a side effect of taking Moderna's COVID vaccine, also known as Spikevax, may result in chronic hives.
Based on a total of 360 European cases, it is assessed that there is a 'probable' connection in 58 cases, while a 'possible' connection exists in 228 cases.
A suspected side effect is categorized as either probable, possible, or not probable.
The category depends on the strength of the evidence that a symptom could be induced by the medication, or whether other factors are considered more likely causes, the agency writes.
Team leader at the Danish Medicines Agency, Martin Zahle Larsen, told that these are preliminary results.
Therefore, further studies are necessary to determine whether there is an actual connection.
"When we say possible, it's because there is a likelihood that it could be caused by the vaccine," the team leader said.
"The side effect comes in with the frequency labeled 'unknown', because we cannot estimate how rare it is."
Most cases of chronic hives have occurred 7-13 days after the third vaccine dose.
It is concluded that individuals who have received Spikevax have three times the risk of developing chronic hives compared to the general population.
Young men are at particularly high risk, it is reported.
"We do not have proof of the cause, but a qualified guess is that it is due to a very active immune system in young men," says Martin Zahle Larsen.
The vaccine works by introducing a piece of genetic code resembling something from the coronavirus into the cells, preparing the immune system to defend itself if one were to become infected.
