Accepted for/Published in: JMIR Public Health and Surveillance
Date Submitted: Oct 19, 2023
Open Peer Review Period: Oct 19, 2023 - Nov 9, 2023
Date Accepted: May 21, 2024
(closed for review but you can still tweet)
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
Ischemic Stroke after Bivalent COVID-19 Vaccination: A Self-Controlled Case Series Study
ABSTRACT
Background:
The potential association between bivalent COVID-19 vaccination and ischemic stroke remains uncertain, despite several studies conducted thus far.
Objective:
The purpose is to evaluate the risk of ischemic stroke following bivalent COVID-19 vaccination.
Methods:
A self-controlled case series study was conducted among members aged ≥12 years who experienced ischemic stroke between September 1, 2022 and March 31, 2023 in a large California health care system. Ischemic strokes were identified using ICD-10 codes in Emergency Department and inpatient settings. Exposures were Pfizer-BioNTech or Moderna bivalent COVID-19 vaccination. Risk intervals were pre-specified as 1–21 days and 1–42 days after bivalent COVID-19 vaccination; all non-risk-interval person-time served as control interval. We conducted overall and subgroup analyses by age, history of SARS-CoV-2 infection, and co-administration of influenza vaccine. When an elevated risk was detected, we performed chart review of ischemic strokes, and re-evaluated the risk.
Results:
With 4933 cases, we found no increased risk within 21-day risk interval across vaccines and by subgroups. However, an elevated risk emerged within 42-day risk interval among individuals <65 years who received co-administration of Pfizer-BioNTech bivalent vaccine and influenza vaccine on the same day; relative incidence (RI) was 2.14 (95% CI, 1.02–4.49). Among those who also had history of SARS-CoV-2 infection, RI was 3.94 (95% CI, 1.10–14.16). After chart review, RIs were 2.35 (95% CI, 0.98–5.65) and 4.33 (95% CI, 0.98–19.11), respectively. Among individuals <65 years who received Moderna bivalent vaccine and had history of SARS-CoV-2 infection, RI was 2.62 (95% CI, 1.13–6.03) before chart review and 2.24 (95% CI, 0.78–6.47) after chart review.
Conclusions:
The potential association between bivalent COVID-19 vaccination and ischemic stroke in the 1-42-day analysis warrants further investigation among individuals <65 years with influenza vaccine co-administration and prior SARS-CoV-2 infection.
Citation
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Copyright
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