Pharmacoepidemiology
COVID-19 Vaccination and Ischemic Stroke in Adults ≥65 Years: Application of Rapid Safety Signal Assessment in Real-World Data Jenny Sun* Jenny Sun Susan Mather Michelle Iannacone Reema Mehta Heather Rubino Kofi Asomaning
Background: In Jan 2023, the US FDA and CDC announced a preliminary statistical signal for ischemic stroke in adults ≥ 65 years administered a booster dose of Pfizer-BioNTech (BNT) Bivalent (BA.4/5) COVID-19 vaccine. The statistical signal was seen in the CDC’s ongoing surveillance but not in other safety systems. Additional real-world evidence was sought to rapidly assess the statistical signal.
Objective: To rapidly estimate the crude incidence of ischemic stroke after Pfizer-BNT Bivalent COVID-19 and comparator vaccinations using near real-time electronic health record (EHR) data.
Methods: Adults aged ≥65 years who received the Pfizer-BNT Bivalent (BA.4/5) COVID-19 vaccine, Moderna Bivalent (BA.4/5) COVID-19 vaccine, or a flu vaccine from 10/01/22-11/30/22 were identified from the Truveta database, which captures daily-refreshed EHR data from 14 US health systems. Individuals were followed from 1-21 days post vaccination for ischemic stroke. Follow-up continued 22-42 days post vaccination for use as a control window. Demographics and the crude incidence of ischemic stroke was summarized using descriptive statistics.
Results: 86,650 individuals received the Pfizer-BNT Bivalent COVID-19 vaccine, 38,342 received the Moderna Bivalent COVID-19 vaccine, and 406,707 received a flu vaccine. There was no difference in the crude incidence of ischemic stroke during the 1-21 day window vs. the 22-42 day window following administration of the Pfizer-BNT Bivalent COVID-19 vaccine (0.05% vs. 0.05%). The crude incidence of ischemic stroke in each window was similar for the other vaccine groups (Moderna: 0.06% vs. 0.07%; flu vaccine: 0.04% vs. 0.04%).
Conclusion: This rapid, large-scale assessment was planned, completed, and disseminated in <2 weeks, quickly providing additional data on the safety of the Pfizer-BNT Bivalent COVID-19 vaccine. Further development of similar infrastructure can provide faster investigation of future drug and vaccine safety signals.