Abstract | OBJECTIVE: DESIGN: Self-controlled case series study using national data on covid-19 vaccination and hospital admissions. SETTING: Patient level data were obtained for approximately 30 million people vaccinated in England between 1 December 2020 and 24 April 2021. Electronic health records were linked with death data from the Office for National Statistics, SARS-CoV-2 positive test data, and hospital admission data from the United Kingdom's health service (NHS). PARTICIPANTS: 29 121 633 people were vaccinated with first doses (19 608 008 with Oxford-AstraZeneca ( ChAdOx1 nCoV-19) and 9 513 625 with Pfizer-BioNTech ( BNT162b2 mRNA)) and 1 758 095 people had a positive SARS-CoV-2 test. People aged ≥16 years who had first doses of the ChAdOx1 nCoV-19 or BNT162b2 mRNA vaccines and any outcome of interest were included in the study. MAIN OUTCOME MEASURES: RESULTS: The study found increased risk of thrombocytopenia after ChAdOx1 nCoV-19 vaccination (incidence rate ratio 1.33, 95% confidence interval 1.19 to 1.47 at 8-14 days) and after a positive SARS-CoV-2 test (5.27, 4.34 to 6.40 at 8-14 days); increased risk of venous thromboembolism after ChAdOx1 nCoV-19 vaccination (1.10, 1.02 to 1.18 at 8-14 days) and after SARS-CoV-2 infection (13.86, 12.76 to 15.05 at 8-14 days); and increased risk of arterial thromboembolism after BNT162b2 mRNA vaccination (1.06, 1.01 to 1.10 at 15-21 days) and after SARS-CoV-2 infection (2.02, 1.82 to 2.24 at 15-21 days). Secondary analyses found increased risk of CVST after ChAdOx1 nCoV-19 vaccination (4.01, 2.08 to 7.71 at 8-14 days), after BNT162b2 mRNA vaccination (3.58, 1.39 to 9.27 at 15-21 days), and after a positive SARS-CoV-2 test; increased risk of ischaemic stroke after BNT162b2 mRNA vaccination (1.12, 1.04 to 1.20 at 15-21 days) and after a positive SARS-CoV-2 test; and increased risk of other rare arterial thrombotic events after ChAdOx1 nCoV-19 vaccination (1.21, 1.02 to 1.43 at 8-14 days) and after a positive SARS-CoV-2 test. CONCLUSION: Increased risks of haematological and vascular events that led to hospital admission or death were observed for short time intervals after first doses of the ChAdOx1 nCoV-19 and BNT162b2 mRNA vaccines. The risks of most of these events were substantially higher and more prolonged after SARS-CoV-2 infection than after vaccination in the same population.
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Authors | Julia Hippisley-Cox, Martina Patone, Xue W Mei, Defne Saatci, Sharon Dixon, Kamlesh Khunti, Francesco Zaccardi, Peter Watkinson, Manu Shankar-Hari, James Doidge, David A Harrison, Simon J Griffin, Aziz Sheikh, Carol A C Coupland |
Journal | BMJ (Clinical research ed.)
(BMJ)
Vol. 374
Pg. n1931
(08 26 2021)
ISSN: 1756-1833 [Electronic] England |
PMID | 34446426
(Publication Type: Journal Article)
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Copyright | © Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY. No commercial re-use. See rights and permissions. Published by BMJ. |
Chemical References |
- COVID-19 Vaccines
- ChAdOx1 nCoV-19
- BNT162 Vaccine
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Topics |
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- BNT162 Vaccine
- COVID-19
(diagnosis, epidemiology, prevention & control)
- COVID-19 Vaccines
(administration & dosage, adverse effects)
- ChAdOx1 nCoV-19
- England
(epidemiology)
- Female
- Humans
- Male
- Middle Aged
- Pandemics
- Risk Assessment
- SARS-CoV-2
- Thrombocytopenia
(epidemiology)
- Thromboembolism
(epidemiology)
- Vaccination
(statistics & numerical data)
- Young Adult
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