COVID-19 VACCINES NOT LINKED TO BLOOD CLOT: MAYO STUDY FINDS
To assess the association of COVID-19 vaccines and non-COVID-19 vaccines with cerebral venous sinus thrombosis (CVST).
Materials and method
Retrospective analysis a cohort of 771,805 vaccination events across 266,094 patients in the Mayo Clinic Health System between 01/01/2017 and 03/15/2021.
The primary outcome was a positive diagnosis of CVST, identified either by the presence of a corresponding ICD code or by an NLP algorithm which detected positive diagnosis of CVST within free-text clinical notes.
For each vaccine the relative risk was calculated by dividing the incidence of CVST in the 30 days following vaccination to that in the 30 days preceding vaccination.
Vaccination events were identified for all FDA-approved COVID-19 vaccines including Pfizer-BioNTech (n = 94,818 doses), Moderna (n = 36,350 doses) and Johnson & Johnson - J&J (n = 1,745 doses). Also identified were the vaccinations events for 10 common FDA-approved non-COVID-19 vaccines (n = 771,805 doses).
There was no statistically significant difference in the incidence rate of CVST in 30-days before and after vaccination for any vaccine in this population. The baseline CVST incidence in the study population between 2017 and 2021 was 45 to 98 per million patient years.
This real-world evidence-based study finds that CVST is rare and is not significantly associated with COVID-19 vaccination in the patient cohort.
Limitations include the rarity of CVST in our dataset, a relatively small number of J&J COVID-19 vaccination events, and the use of a population drawn from recipients of a SARS-CoV-2 PCR test in a single health system.
Source: PR Newswire
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