Disproportionality analysis of adverse neurological and psychiatric reactions with the ChAdOx1 (Oxford-AstraZeneca) and BNT162b2 (Pfizer-BioNTech) COVID-19 vaccines in the United Kingdom

Abstract

ABSTRACTObjectiveThe information on neurologic or psychiatric adverse reactions to the COVID-19 vaccines is limited. Our objective was to examine the odds of neurological and psychiatric adverse reactions to BNT162b2 (Pfizer-BioNTech) and ChAdOx1 (Oxford-AstraZeneca) COVID-19 vaccines.MethodsWe analyzed all Adverse Vaccine Reaction reports to the United Kingdom Medicines and Healthcare products Regulatory Agency between December 9, 2020 and June 30, 2021 that mentioned the BNT162b2 or ChAdOx1 vaccines. We compared the rates of adverse neurological and psychiatric reactions with ChAdOx1 to those with BNT162b2. P-values were obtained by a Bonferroni-adjusted Z-test for proportions.ResultsAs of June 30, 2021, 53.2 M doses of ChAdOx1 and 46.1 M doses of BNT162b2 had been administered. We extracted information from 300,518 distinct reports. The number of individual adverse neurologic or psychiatric reaction reports were less than 200/M doses administered, except headache which was reported in 1,550 and 395 cases/M doses of ChAdOx1 and BNT162b2, respectively. Compared to BNT162b2, cerebral hemorrhagic or thrombotic events, headaches and migraines, Guillain-Barre syndrome and paresthesias, tremor and freezing, delirium, hallucinations, nervousness, poor sleep quality, and postural dizziness were more frequently reported with ChAdOx1. Reactions more frequently reported with BNT162b2 than ChAdOx1 were Bell’s palsy, facial paralysis, dysgeusia, anxiety, and presyncope or syncope.ConclusionSignificant differences in the neurologic and psychiatric adverse event profiles of the ChAdOx1 and BNT162b2 vaccines may exist, emphasizing the need for additional research. The beneficial and protective effects of the COVID-19 vaccines far outweigh the low potential risk of neurologic and psychiatric reactions.