Hwang J, Park SH, Lee SW, et al. - A significant correlation of fibrinogen levels, age, platelet count, and the presence of intracerebral hemorrhage (ICH) and cerebral venous thrombosis (CVT) was observed with mortality following thrombosis with thrombocytopenia syndrome (TTS) after adenoviral COVID-19 vaccine administration.

• Included were a total of 6 case series and 13 case reports (64 patients) of TTS after ChAdOx1 nCoV-19 vaccination.

• TTS after ChAdOx1 nCoV-19 vaccination was linked with an overall mortality of 35.9% (23/64).

• The following factors were significantly linked with death: age ≤ 60 years, platelet count < 25 × 10³/µL, fibrinogen <150 mg/dL, the presence of ICH, and the presence of CVT.

• A novel scoring system, FAPIC (fibrinogen, age, platelet count, ICH, and CVT), was developed including these factors (1 point each).

• The C-statistic for the FAPIC score was 0.837.

• There appeared an increase in expected mortality with each point increase in the FAPIC score.