There is something very important to keep in mind here. This is a self-reporting system. The US has a similar system. It doesn't take long to find this disclaimer:

The information on this website relates to suspected side effects , i.e. medical events that have been observed following the use of a medicine, but which are not necessarily related to or caused by the medicine.

Information on suspected side effects should not be interpreted as meaning that the medicine or the active substance causes the observed effect or is unsafe to use. Only a detailed evaluation and scientific assessment of all available data allows for robust conclusions to be drawn on the benefits and risks of a medicine.

The European Medicines Agency publishes these data so that its stakeholders, including the general public, can access information that European regulatory authorities use to review the safety of a medicine or active substance. Transparency is a key guiding principle of the Agency.

http://www.adrreports.eu/en/index.html

I'm only posting this for the sake of transparency and providing information, because the OP provides an incomplete picture. There are many things to take into account here, but this system works as follows: I took a vaccine (or any medicine really), I had a reaction (related or not), I report it to the system. It is an important system that gives researchers information that they may follow up on, but the above disclaimer is very important. The takeaway is that with any mass-administered substance, you will have a large number of reports.

Edit: This post doesn't follow the dogma related to vaccines on this website (vaccine bad, orange man bad for pushing for creation of vaccine, facts challenging dogma bad). Bring on the downvotes, lol.

There is something very important to keep in mind here. This is a self-reporting system. The US has a similar system. It doesn't take long to find this disclaimer:

The information on this website relates to suspected side effects , i.e. medical events that have been observed following the use of a medicine, but which are not necessarily related to or caused by the medicine.

Information on suspected side effects should not be interpreted as meaning that the medicine or the active substance causes the observed effect or is unsafe to use. Only a detailed evaluation and scientific assessment of all available data allows for robust conclusions to be drawn on the benefits and risks of a medicine.

The European Medicines Agency publishes these data so that its stakeholders, including the general public, can access information that European regulatory authorities use to review the safety of a medicine or active substance. Transparency is a key guiding principle of the Agency.

http://www.adrreports.eu/en/index.html

I'm only posting this for the sake of transparency and providing information, because the OP provides an incomplete picture. There are many things to take into account here, but this system works as follows: I took a vaccine (or any medicine really), I had a reaction (related or not), I report it to the system. It is an important system that gives researchers information that they may follow up on, but the above disclaimer is very important. The takeaway is that with any mass-administered substance, you will have a large number of reports.