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Adverse reactions

The use of COVID-19 vaccines, like any other vaccines or pharmaceuticals, may be associated with adverse reactions. However, not all users get them, or the adverse reactions may be very mild and transient.

There may also be serious adverse reactions. Pharmaceutical trials always include a limited number of patients, and the very rare adverse reactions do not necessarily appear among the trial subjects.

The information on the efficacy and safety of vaccines and medicines is expanding and becoming more precise as the products are used by larger numbers of people.

It is therefore important that the information on all possible adverse reactions is gathered. This information is the basis for the continuous safety follow-up by pharmaceutical companies and the authorities. 

Based on the follow-up, we also get information on whether certain adverse reactions appear, for example, in certain population groups more frequently than in others, or whether the volume of already known adverse effects is growing from earlier observations. Based on this data, it will be possible to limit the use of a pharmaceutical product or vaccine and ensure their safe and correct use.

A notification of a suspected adverse reaction caused by a medicine or vaccine can be filed by anyone who becomes aware of such a reaction, also by the medicine user or a vaccinated individual. A mere suspicion of an adverse reaction to a medicine is enough to file a notification. In Finland, the notifications are made to the Finnish Medicines Agency Fimea or the company holding the marketing authorisation of the medicine or vaccine.

Further reading


Page published 28.04.2021 | Page edited 29.10.2021