U00-U49: Provisional assignment of new diseases of uncertain etiology or emergency use

U12: COVID-19 vaccines causing adverse effects in therapeutic use

COVID-19 vaccines may cause adverse effects in therapeutic use, as denoted under the ICD-10 WHO group U12. These effects can vary considerably and are usually temporary, often signaling that the body is building protection against the virus. Common symptoms include pain and swelling in the arm where you received the shot, as well as fever, fatigue, headache, muscle pain, chills, and nausea. It's lack of these responses does not suggest the vaccine is ineffective. These symptoms usually disappear on their own within a few days. However, some individuals may experience more serious reactions, such as severe allergic reactions, although these are extremely rare. It is important to distinguish between these side effects, which occur shortly after vaccination, and potential vaccine-related injuries that may manifest later. The latter are still being studied and will require ongoing monitoring and research.