The Norwegian Institute of Public Health (NIPH) has suspended vaccination with the AstraZeneca COVID-19 vaccine after we became aware of cases of serious suspected adverse reactions involving a combination of blood clots, bleeding and low platelet count. As of 23 March, five such cases had been reported, three of which concerned deaths and the other two are receiving treatment in hospital.
The Norwegian Medicines Agency believes there is a probable link between the AstraZeneca vaccine and these rare cases. Further research is needed to clarify what is triggering the rare combination of symptoms. NIPH will reach a decision concerning future use of the AstraZeneca vaccine and will issue an update at the end of the week commencing 22 March.
The reports of adverse reactions that we have received do not provide a basis for revising the current recommendations regarding vaccination with the Comirnaty (BioNtech/Pfizer) and Moderna COVID-19 vaccines.
Click here to go to an overview of reports of suspected adverse reactions (the adverse reactions report)
Most of the reports concern common adverse and expected reactions, such as pain at the injection site, headache, general malaise with fever, fatigue, nausea and pain in the body. These adverse reactions are known from the studies which formed the basis for the vaccine authorisations.
Signal detection – detecting possible links
The Norwegian Medicines Agency, European Medicines Agency (EMA), World Health Organization (WHO) and pharmaceutical companies review the adverse reaction reports and prepare statistics in order to detect unknown adverse reactions. In addition, the Norwegian Medicines Agency has established procedures for identifying individual reports concerning particularly serious suspected adverse reactions, or groups with similar reports which should be analysed in more detail. This is known as signal detection.
These adverse reaction signals undergo a validation process where we look in more detail at whether the information provided in the adverse reaction report is sufficient. We can then assess whether there are other obvious causes behind the suspected adverse reactions. We also consider whether the suspected adverse reactions could be linked to the vaccine. If we suspect this to be the case, we will investigate the signal further. It may then be appropriate to obtain more information and carry out further analyses. Known adverse reactions are not set up as a signal.
The following signals are currently being closely monitored for all COVID-19 vaccines in the European medicines collaboration:
- Blood clots (thromboses)
- ITP (immunological thrombocytopenia)
- Swelling in vaccinated persons who have had dermal filler injections
The receipt of a single report of a suspected adverse reaction rarely constitutes a signal, because it can be difficult to assess possible causal links based on a single event. The work relating to the signals is therefore carried out at international level, enabling small numbers of cases from different countries to be combined and collectively made into a valid signal.
How to report adverse reactions
Health professionals are obliged to report suspected new, unexpected and serious adverse reactions via melde.no as soon as possible (remember to quote the batch number). Staffing levels at the Norwegian Institute of Public Health (NIPH) have been strengthened, and RELIS is assisting NIPH in the assessment of reports, enabling them to be assessed more rapidly. The processing of serious reports is given priority, and these reports are processed as soon as possible.
The general population can report adverse reactions via helsenorge.no, but you should consult a doctor or other health professional in the case of suspected serious or unexpected adverse reactions following vaccination. It is not necessary to report a possible adverse reaction if a health professional has already reported the reaction.
International cooperation
Reports of adverse reactions following vaccination are followed up by the Norwegian Medicines Agency in partnership with the Norwegian Institute of Public Health and the regional medicines information and pharmacovigilance centres (RELIS). The Norwegian Medicines Agency is responsible for the National ADR Register, and exchanges adverse reaction data with the European Medicines Agency (EMA) and the World Health Organization (WHO). This provides us with a better basis for assessing causation and implementing measures to safeguard patient safety.
