U12.9: Unassigned code U12.9

You have suffered one or more adverse side effects after being vaccinated against the SARS-CoV-2 coronavirus.

When someone is infected by this coronavirus it may trigger the Covid-19 disease. The aim of the vaccination is to prevent Covid-19.

2 different types of vaccines are used for the vaccinations. The vector vaccines are one type. They contain viruses that pose no risk to humans. A small piece of the coronavirus blueprint has been packed into these harmless viruses. The mRNA vaccines are the other type. In the case of mRNA vaccines, a small piece of the coronavirus blueprint has been packed into a tiny particle of lipid. Once the vaccines are injected into the muscle the small piece of the coronavirus blueprint is transported to the body’s cells.

The small piece of the coronavirus blueprint stimulates the body’s cells to produce the same pieces of coronavirus for a short time. In contrast to a real infection, however, these are not complete coronaviruses, but rather small fragments of the virus surface. The small piece of the coronavirus blueprint is then broken down and it does not remain in the body’s cells. The immune system now recognizes a part of the virus surface and it produces certain substances that can combat the coronaviruses. If someone comes into contact with coronaviruses later on, the immune system can act against them more rapidly. So the coronaviruses are then unable to damage the body as badly.

You have suffered an unintended effect after your vaccination. These include symptoms such as pain, and redness at the vaccination site. You can then get a fever, a rash or diarrhea. You may also feel very tired or have pain in your limbs. Your lymph nodes may thicken. These symptoms indicate that the body is dealing with the vaccine and they usually only last for a few days.

In rare cases a serious adverse effect can also occur. For example, facial palsies can occur. Another possibility is an inflamed heart. Blood may also clump and it can then block the blood vessels. When blood clumps certain substances and cells are used up. These substances and cells normally seal bleeding wounds. The person may then bleed more heavily than usual.

People can have an allergic reaction to a vaccination. With an allergy, the immune system reacts too strongly to a foreign substance, such as a vaccine component.

Additional indicator

On medical documents, the ICD code is often appended by letters that indicate the diagnostic certainty or the affected side of the body.

  • G: Confirmed diagnosis
  • V: Tentative diagnosis
  • Z: Condition after
  • A: Excluded diagnosis
  • L: Left
  • R: Right
  • B: Both sides

Further information


This information is not intended for self-diagnosis and does not replace professional medical advice from a doctor. If you find an ICD code on a personal medical document, please also note the additional indicator used for diagnostic confidence.
Your doctor will assist you with any health-related questions and explain the ICD diagnosis code to you in a direct consultation if necessary.


Provided by the non-profit organization “Was hab’ ich?” gemeinnützige GmbH on behalf of the Federal Ministry of Health (BMG).