Neurological Events Reported after COVID-19 Vaccines: An Analysis of VAERS

Abstract

Objective: To identify the rates of neurological events following administration of mRNA (Pfizer, Moderna) or adenovirus vector (Janssen) vaccines in the U.S..

Methods: We utilized publicly available data from the U.S. Vaccine Adverse Event Reporting System (VAERS) collected between January 1, 2021-June 14, 2021. All free text symptoms that were reported within 42 days of vaccine administration were manually reviewed and grouped into 36 individual neurological diagnostic categories. Post-vaccination neurological event rates were compared between vaccine types and to age-matched baseline incidence rates in the U.S. and rates of neurological events following COVID.

Results: Of 306,907,697 COVID vaccine doses administered during the study timeframe, 314,610 (0.1%) people reported any adverse event and 105,214 (0.03%) reported neurological adverse events in a median of 1 day (IQR0-3) from inoculation. Guillain-Barre Syndrome (GBS), and cerebral venous thrombosis (CVT) occurred in fewer than 1 per 1,000,000 doses. Significantly more neurological adverse events were reported following Janssen (Ad26.COV2.S) vaccination compared to either Pfizer-BioNtech (BNT162b2) or Moderna (mRNA-1273; 0.15% versus 0.03% versus 0.03% of doses, respectively,P<0.0001). The observed-to-expected ratios for GBS, CVT and seizure following Janssen vaccination were ≥1.5-fold higher than background rates. However, the rate of neurological events after acute SARS-CoV-2 infection was up to 617-fold higher than after COVID vaccination.

Interpretation: Reports of serious neurological events following COVID vaccination are rare. GBS, CVT and seizure may occur at higher than background rates following Janssen vaccination. Despite this, rates of neurological complications following acute SARS-CoV-2 infection are up to 617-fold higher than after COVID vaccination. This article is protected by copyright. All rights reserved.

FIGURE 1

Neurological adverse events per 1,000,000 vaccine doses reported in VAERS stratified by COVID vaccine type. Note that the rates of headache, fatigue, dizziness and syncope exceed the y‐axis scale for the Janssen vaccine and event rates are listed above these bars. Significance was set at p < 0.0004 after Bonferroni correction for multiple comparisons. ADEM = acute disseminated encephalomyelitis; ALS = amyotrophic lateral sclerosis; IPH/IVH = intraparenchymal hemorrhage/intraventricular hemorrhage; TIA = transient ischemic attack. # p < 0.0004 Janssen v Pfizer, Janssen v Moderna, and Pfizer v Moderna; *p < 0.0004 Janssen v Pfizer, and Janssen v Moderna; ^p < 0.0004 Janssen v Pfizer, and Pfizer v Moderna; !p < 0.0004 Janssen v Moderna, and Pfizer v Moderna; & p < 0.0004 Janssen v Moderna; ❡ p < 0.0004 Pfizer v Moderna. [Color figure can be viewed at www.annalsofneurology.org]

FIGURE 2

Median age and sex proportions for each adverse event reported in VAERS between January 1, 2021‐June 14, 2021, inclusive of all COVID vaccine brands. [Color figure can be viewed at www.annalsofneurology.org]

FIGURE 3

Median time (days) from vaccine injection to adverse event onset, inclusive of all COVID vaccine types, and proportion of events which were reported after the first or second dose of a mRNA vaccine (using data available in 235,293/275,575 [85%] of patients who received either Pfizer or Moderna vaccines). [Color figure can be viewed at www.annalsofneurology.org]