Rhabdomyolysis after COVID-19 Comirnaty Vaccination: A Case Report.

Rhabdomyolysis is an acute disruption in skeletal muscle integrity, leading to the rapid release of 4 muscle contents into the bloodstream, such as creatine kinase (CK). It can have various causes, including infections. Throughout the pandemic, multiple cases of rhabdomyolysis following COVID-19 infections have been reported. However, rhabdomyolysis subsequent to COVID-19 vaccinations appears to be relatively rare. Here, we report such a case after a second COVID-19 Comirnaty (BioNTech/Pfizer) vaccination. Our patient developed rhabdomyolysis 1 day after the second Comirnaty vaccination with high creatine kinase (CK) levels, generalized weakness, and kidney failure. CK levels and muscle weakness resolved after treatment with intravenous fluids, but unfortunately, he remained hemodialysis dependent after discharge. To our knowledge, this is one of the first case reports describing a patient with rhabdomyolysis after a Comirnaty vaccination. However, as millions of people have received the Comirnaty vaccine, it is unclear whether the rhabdomyolysis in our patient is a rare side effect or an unrelated, coincidental event. Large observational studies are needed to elucidate the causality between the Comirnaty vaccination and rhabdomyolysis. Awareness is warranted in patients with myalgia and muscle weakness shortly after COVID-19 vaccination, in order to initiate treatment early and prevent life-threatening complications.