Thrombosis with thrombocytopenia syndrome following adenovirus vector-based vaccines to prevent COVID-19: Epidemiology and clinical presentation in Spain

Abstract

Background: We describe the epidemiological and clinical characteristics of thrombosis with thrombocytopenia syndrome (TTS) cases reported in Spain. Methods: We included all cases of venous or arterial thrombosis with thrombocytopenia following administration of adenoviral vector vaccines (AstraZeneca or Janssen) against COVID-19 disease between 1 February and 26 September 2021. We describe the crude rate and the standardised morbidity ratio. We assessed the predictors of mortality. Results: Sixty-one cases were reported and 45 fulfilled eligibility criteria; 82% of patients were women. The crude TTS rate was 4 cases/1 000 000 doses, and 14-15 cases/1 000 000 doses among patients aged 30-49 years. The number of observed cases of cerebral venous thrombosis was 6-18 times higher than that expected in patients younger than 49 years. Symptoms started a median (quartiles 1 and 3 [Q1-Q3]) of 10 (7-14) days after vaccination. Eighty percent (95% confidence interval [CI]: 65%-90%) had thrombocytopenia at the time of the emergency department visit, and 65% (49%-78%) had D-dimer levels > 2000 ng/mL. Patients had thromboses affecting multiple locations in 36% of cases and fatal outcomea in 24%. Platelet nadir 2.000 ng/mL). La trombosis fue de múltiples localizaciones en 36% y fatal en 24% de los pacientes. Un valor nadir de trombocitopenia < 50.000/μL (odds ratio (OR): 7,4; IC95%: 1,2-47,5) y la presencia de hemorragia cerebral (OR: 7,9; IC95%: 1,3-47,0) se asociaron a un desenlace fatal. Conclusiones: Debe sospecharse el STT en pacientes que presenten síntomas unos 10 días tras la vacunación y presenten trombocitopenia y/o elevación de dímero D.

Keywords

• MeSH Terms
• COVID-19
• Efectos adversos de medicamentos y reacciones adversas
• Vacunas
• Embolia y trombosis
• Trastornos plaquetarios