Vaccine-induced thrombotic thrombocytopenia, a rare but severe case of friendly fire in the battle against COVID-19 pandemic: What pathogenesis?

Cerebral venous sinus thrombosis (CVST) associated with SARS-CoV-2 vaccines: clues for an immunopathogenesis common to CVST observed in COVID-19

Severe acute respiratory syndrome coronavirus type 2 has been responsible for an unprecedented pandemic, and nowadays, several vaccines proved to be effective and safe, representing the only available strategy to stop the pandemic. While millions of people have safely received vaccine, rare and unusual thrombotic events have been reported and are undergoing investigations to elucidate their nature. Understanding initial trigger, underlying pathophysiology and the reasons for specific site localization of thrombotic events are a matter of debate.

We here propose that rare cases of cerebral venous sinus thrombosis, a clinical event that may rapidly evolve to brain death, reported after COVID-19 vaccine, might be consequent to an immune response resulting in inflamed/damaged endothelium, an event similar to that described for cases of cerebral venous sinus thrombosis reported during COVID-19 and not necessarily related to anti-Platelets Factor 4 antibodies, as recently described. Remarkably, in the two patients presenting at our hospital with cerebral venous sinus thrombosis and evolved to brain death, proper tissue perfusion and function maintenance allowed organ donation despite extensive thrombosis in the organ donors, with favorable outcome at 6 months.

Increased vigilance, close multidisciplinary collaboration, and further prospective research will help to better elucidate a very rare and still not fully understood pathophysiological event associated with vaccines for severe acute respiratory syndrome coronavirus 2.