​​The adverse reaction report summarises all reports of suspected adverse reactions that we have assessed to date following the vaccination of more than 2.8 million people. Events following vaccination are reported on the basis of suspicions, which means that there is not necessarily any causal relationship. The challenge is to distinguish symptoms and medical conditions which occur randomly from those which could be linked to vaccination. All reports are included in the report, regardless of whether or not an event is believed to be linked to vaccination. 


Reports of serious events are given priority and assessed first. The figures therefore do not give a complete picture of the distribution between serious and non-serious events. 

Click here to go to an overview of reports of suspected adverse reactions (the adverse reactions report)​ ​

A vital tool 

The reporting scheme is a vital tool in the monitoring of vaccines.  The reports submitted by health professionals and members of the public give us signals as to whether there are any events that we should investigate further. It is not known with any certainty what proportion of these events are being reported, while a report does not necessarily indicate a causal relationship. As a result, the number of reports submitted to the Norwegian Medicines Agency cannot normally be used to determine how often or how many adverse reactions a vaccine could give rise to, or to compare the safety profiles of different vaccines.  

Same type of vaccines being offered 

The two vaccines offered under the vaccination programme, Comirnaty (BioNTech/Pfizer) and Spikevax (Moderna), are both mRNA vaccines and provide good protection against COVID-19. These vaccines can give rise to a number of ailments during the first two or three days after vaccination. These are normally transient adverse reactions, such as pain around the injection area, headaches and general malaise with an accompanying fever. These adverse reactions are known from studies and are mentioned in the product information for the vaccines. They usually appear on the first or second day after vaccination and last around two to three days.   

The studies suggest that slightly more people experience these common and transient adverse reactions following vaccination with Spikevax than with Comirnaty.  Serious adverse reactions are rare for both vaccines.  

“The adverse reaction profile of the vaccines is similar. There is therefore no reason to prefer one vaccine over the other or to delay vaccination. You should take the vaccine you’re offered,” urges Medical Director Steinar Madsen. 

The Norwegian Medicines Agency has previously described cases of what is known as "COVID arm", a delayed local reaction in the vaccination arm which normally occurs five to ten days after vaccination. Experience suggests that this reaction occurs more frequently following vaccination with Spikevax than with Comirnaty. ​

Please remember to include the following information when reporting adverse reactions: ​

  • name of the vaccine and date of vaccination 
  • detailed description of the sequence of events 
  • when the adverse reaction first started 
  • whether the reaction is persistent or has passed 
  • any previous medical conditions and the taking of medication 
  • if/when you have taken a COVID-19 test, and the result 
  • whether the reaction occurred after the first or second dose 
  • whether a different type of vaccine was given as the second dose 
  • results of any blood tests 
  • whether a doctor has been contacted  ​

It is particularly important to report reactions where any of the following are suspected: 

  • new adverse reactions not referred to in the patient information leaflet
  • unexpected adverse reactions
  • ​serious adverse reactions
  • vaccine failure (severe COVID-19 following full vaccination)  


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