An observational study with a case-control design was conducted to analyze the prevalence of cerebral venous thrombosis (CVT) in adenovirus vector-based COVID19 vaccine recipients. All published cases and case series between March 01 and April 30, 2021, were screened, and specific reports from the United States Centers for Disease Control and Prevention and the European Medicines Agency providing patient-level data were assessed. 77 cases of CVT were identified. Patients’ age was below 40 in 46.5%, below 60 in 95.8%, and between 60 and 69 years in 4.2% cases. 87.9% of women were affected by CVT.
Vaccine-associated CVT was lower in men. 5.2% of patients used contraceptives and 1.3% of patients received estrogen therapy. After vaccination, the first symptoms of CVT were observed in 8 days. 49.4% of the patients reported the presence of headaches. Among the patients with headaches, 92.1% of patients reported the presence of other systemic or neurological symptoms. Intracranial hemorrhage was present in 42.9% of cases, multiple location thrombosis was reported in 24.7% of cases, and 24.7% succumbed to the disease.
Headache attributed to vaccine-related cerebral venous sinus thrombosis was reported in patients on or after the 6th-day post-vaccination. The CVT-related clinical symptoms started earlier in patients with headaches when compared to patients without headaches. In patients with CVT, the presence of headache was associated with the presence of intracranial hemorrhage.
To conclude, delayed onset of headache following an adenovirus vector-based COVID-19 vaccine is associated with CVT. Patients with new-onset headache, 1 week after vaccination with an adenovirus vector-based vaccine, should receive a thorough clinical evaluation and CVT must be considered in the diagnostic work-up.