The article explains the rare and dangerous side effects of the COVID-19 vaccines. mRNA vaccines from Pfizer-BioNTech and Moderna cause myocarditis, inflammation of the heart muscle[1][3]. Janssen vaccine can induce thrombosis with thrombocytopenia (TTS) and Guillain-Barré syndrome[1]. Adenovirus vaccines such as AstraZeneca and Johnson & Johnson lead to VITT syndrome through antibodies against the PF4 protein, which activates platelets and causes both blood clots and bleeding[4][6][7]. About 900 cases of VITT following these vaccines have been reported in Europe, including 200 deaths[4]. A study identified genetic variants of antibody light chains that enhance binding to PF4 and trigger a chain reaction[4]. Intramuscular vaccination can cause specific shoulder injuries, such as acute bursitis or tendon and nerve damage[1]. Future studies may change conclusions about causality where the evidence is insufficient[1].