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Course: Incidence of Cerebral Venous Thrombosis Following SARS-CoV-2 Infection vs mRNA SARS-CoV-2 Vaccination in Singapore

CME Credits: 1.00

Released: 2022-03-17

Key Points

Question What is the risk of cerebral venous thrombosis (CVT) after diagnosis of SARS-CoV-2 infection compared with after messenger RNA (mRNA)-based SARS-CoV-2 vaccination?
Findings In this observational cohort study of 62,447 individuals with SARS-CoV-2 infection and 3,006,662 individuals who received mRNA-based SARS-CoV-2 vaccine in Singapore from January 23, 2020, to August 3, 2021, the incidence rate ratio of CVT requiring hospitalization within 6 weeks of SARS-CoV-2 infection was 32 times higher compared with after mRNA-based SARS-CoV-2 vaccination.
Meaning These findings suggest that the risk of CVT after SARS-CoV-2 infection is higher than after mRNA-based SARS-CoV-2 vaccination.

Abstract

Importance Reports of cerebral venous thrombosis (CVT) after messenger RNA (mRNA)-based SARS-CoV-2 vaccination has caused safety concerns, but CVT is also known to occur after SARS-CoV-2 infection. Comparing the relative incidence of CVT after infection vs vaccination may provide a better perspective of this complication.
Objective To compare the incidence rates and clinical characteristics of CVT following either SARS-CoV-2 infection or mRNA-based SARS-CoV-2 vaccines.
Design, Setting, and Participants Between January 23, 2020, and August 3, 2021, this observational cohort study was conducted at all public acute hospitals in Singapore, where patients hospitalized with CVT within 6 weeks of SARS-CoV-2 infection or after mRNA-based SARS-CoV-2 vaccination (BNT162b2 [Pfizer-BioNTech] or mRNA-1273 [Moderna]) were identified. Diagnosis of SARS-CoV-2 infection was based on quantitative reverse transcription-polymerase chain reaction or positive serology. National SARS-CoV-2 infection data were obtained from the National Centre for Infectious Disease, Singapore, and vaccination data were obtained from the National Immunisation Registry, Singapore.
Exposures SARS-CoV-2 infection or mRNA-based SARS-CoV-2 vaccines.
Main Outcomes and Measures Clinical characteristics, crude incidence rate (IR), and incidence rate ratio (IRR) of CVT after SARS-CoV-2 infection and after mRNA SARS-CoV-2 vaccination.
Results Among 62,447 individuals diagnosed with SARS-CoV-2 infections included in this study, 58,989 (94.5%) were male; the median (range) age was 34 (0-102) years; 6 CVT cases were identified (all were male; median [range] age was 33.5 [27-40] years). Among 3,006,662 individuals who received at least 1 dose of mRNA-based SARS-CoV-2 vaccine, 1,626,623 (54.1%) were male; the median (range) age was 50 (12-121) years; 9 CVT cases were identified (7 male individuals [77.8%]; median [range] age: 60 [46-76] years). The crude IR of CVT after SARS-CoV-2 infections was 83.3 per 100,000 person-years (95% CI, 30.6-181.2 per 100,000 person-years) and 2.59 per 100,000 person-years (95% CI, 1.19-4.92 per 100,000 person-years) after mRNA-based SARS-CoV-2 vaccination. Six (66.7%) received BNT162b2 (Pfizer-BioNTech) vaccine and 3 (33.3%) received mRNA-1273 (Moderna) vaccine. The crude IRR of CVT hospitalizations with SARS-CoV-2 infection compared with those who received mRNA SARS-CoV-2 vaccination was 32.1 (95% CI, 9.40-101; P?<?.001).
Conclusions and Relevance The incidence rate of CVT after SARS-CoV-2 infection was significantly higher compared with after mRNA-based SARS-CoV-2 vaccination. CVT remained rare after mRNA-based SARS-CoV-2 vaccines, reinforcing its safety.


Educational Objective
To identify the key insights or developments described in this article


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