Rhabdomyolysis Following Administration of Comirnaty®

Introduction: Vaccination against COVID-19 is essential to control the pandemic. The vaccines developed so far have good safety profiles but full knowledge of adverse effects will only be acquired with time and through case reports. Case Description: We present the case of a man admitted with rhabdomyolysis 3 days after receiving his first dose of the Pfizer coronavirus vaccine Comirnaty® Other traumatic, infectious, endocrine, electrolyte disturbance and autoimmune causes of rhabdomyolysis were excluded. The temporal relationship between vaccine administration and disease onset indicated possible causality. The patient had a favourable evolution after receiving fluids and completely recovered. To our knowledge, there have been only 69 reports of rhabdomyolysis following Comirnaty® administration in Europe, as stated by the European Medicines Agency, and this is the first case report in Portugal. Discussion: When a patient presents with rhabdomyolysis without an obvious traumatic or exertional cause, other aetiologies need to be excluded. Drug use is one of the most common causes of rhabdomyolysis in adults. Conclusion: We present a case compatible with an adverse effect of Comirnaty® in order to raise awareness of this condition in vaccinated patients.