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Oral Presentation

Vaccines

Session: Evaluating the Vaccines Against the Nasty Bugs: Safety First Round II

COVID-19 Vaccination and Acute Neurological Events in England: A Self-controlled Case Series Using the OpenSAFELY Platform

Sunday, August 28, 2022

2:00 PM – 2:15 PM CEST

Location: C1M1

Publication Number: 273

Background: COVID-19 vaccines save lives, but it is important to identify and quantify the risk of rare adverse events.

Objectives: To investigate the potential association between vaccination against COVID-19 and Guillain-Barré syndrome (GBS), transverse myelitis and Bell's palsy, by vaccine brand.

Methods: With the approval of NHS England we analysed primary care data from >17 million patients in England in the OpenSAFELY platform linked to emergency care, hospital admission and mortality records to identify cases of GBS, transverse myelitis and Bell's palsy occurring between 1st Jul 2020 and 7th July 2021. We used a self-controlled case series design, controlling for time-invariant confounding, to estimate the incidence rate ratio (IRR) for each outcome in pre-specified risk periods following the first and second dose of each brand of vaccine (4—42 days for GBS, 4—28 days for transverse myelitis and Bell's palsy) compared to a within-person baseline, using conditional Poisson regression. We included a pre-exposure period (28 days for GBS and transverse myelitis, 14 for Bell's palsy) to account for potential delays in vaccination following the outcomes.

Results: Among 7,783,441 Astra Zeneca (AZ) vaccinees, there was an increased rate of GBS (N=517; 2.85; 95% CI2.33—3.47) and Bell's palsy (N=5,350; 1.39; 1.27—1.53) following a first dose of the AZ vaccine, corresponding to 11.0 additional cases of GBS and 17.9 cases of Bell's palsy per 1 million vaccinees, but no evidence of an association with transverse myelitis (N=199; 1.51; 0.96—2.37). Among 5,729,152 Pfizer vaccinees, there was no evidence of any association with GBS (N=283; 1.09; 0.75—1.57), transverse myelitis (N=109; 1.62; 0.86—3.03) or Bell's palsy (N=3,984; 0.89; 0.78—1.01). Among 258,238 Moderna vaccine recipients there was no evidence of an association with Bell's palsy (N=3,609; 0.89; 0.76—1.03); numbers were too low to look at other outcomes. Results were robust in numerous sensitivity analyses, including adjustment for calendar time, restricting the baseline time period to post-vaccination time only and (in analyses of Bell's palsy) restricting to cases recorded in primary care. There was no increased rate of GBS following a second dose of either AZ or Pfizer vaccines; weak evidence of an association between a second dose of AZ and Bell's Palsy was not robust to sensitivity analyses. 12.6% of Bell's palsy cases were recorded in emergency care only.

Conclusions: We observed an increased rate of GBS and Bell's palsy following the first dose of AZ COVID-19 vaccine. The attributable risk, assuming a causal effect, was low. Record linkage allowed for greater power when studying these rare events, as well as the identification of Bell's palsy cases that would otherwise have been missed.

Presenting Author(s)

Anna Schultze

London School of Hygiene and Tropical Medicine
London, United Kingdom

Slides

Co-Author(s)

JW

Jemma Walker

London School of Hygiene and Tropical Medicine
London, United Kingdom
John R. Tazare

London School of Hygiene and Tropical Medicine
London School of Hygiene & Tropical Medicine
London, United Kingdom
AT

Arina Tamborska

NIHR Health Protection Research Unit (HPRU) in Emerging and Zoonotic Infections, Institute of Infection, Veterinary and Ecological Science, University of Liverpool AND Division of Neurology, Walton Centre NHS Foundation Trust, Liverpool, L9 7LJ, United Kingdom
BS

Bhagteshwar Singh

NIHR Health Protection Research Unit (HPRU) in Emerging and Zoonotic Infections, Institute of Infection, Veterinary and Ecological Science, University of Liverpool AND Tropical and Infectious Diseases Unit, Royal Liverpool University Hospital, Liverpool, L7 8XP, United Kingdom
Katherine Donegan, PhD

Pharmacoepidemiology Research and Intelligence Manager
Medicine and Healthcare products Regulatory Agency (UK)
London, United Kingdom
JS

Julia Stowe

UK Health Security Agency, United Kingdom
CM

Caroline Morton

The DataLab, Nuffield Department of Primary Care Health Sciences, University of Oxford, OX26GG, United Kingdom
SE

Stephen Evans, MSc

Professor
Department of Medical Statistics, London School of Hygiene and Tropical Medicine, United Kingdom
TS

Tom Solomon

. NIHR Health Protection Research Unit (HPRU) in Emerging and Zoonotic Infections, Institute of Infection, Veterinary and Ecological Science, University of Liverpool AND Division of Neurology, Walton Centre NHS Foundation Trust, Liverpool, L9 7LJ, United Kingdom
NA

Nick Andrews

Senior Statistician
UK Health Security Agency, United Kingdom
ID

Ian Douglas, PhD

Professor
Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
BG

Ben Goldacre

The DataLab, Nuffield Department of Primary Care Health Sciences, University of Oxford, OX26GG, United Kingdom
LS

Liam Smeeth

London School of Hygiene and Tropical Medicine, United Kingdom
HM

Helen McDonald

Clinical Assistant Professor
London School of Hygiene and Tropical Medicine, United Kingdom