Evaluating the safety of XBB.1.5-containing COVID-19 mRNA vaccines using a self-controlled case series study
Yuanyi Pan, Yun Han, Chuan Zhou, Lili Zhao, Jie Zheng, Xianwei Ye, Yongqun He, Christopher G. Chute
Abstract
The safety of XBB.1.5-containing COVID-19 mRNA vaccines warrants investigation. We assessed the relative risk of 15 adverse events following the XBB.1.5 vaccination using a self-controlled case series study design with data from the National COVID Cohort Collaborative (N3C) from September 11, 2023, to June 1, 2024 in the USA. Based on a baseline population of 244,494 patients, adverse events included Guillain-Barré syndrome, seizure, non-hemorrhagic stroke and transient ischemic attack, hemorrhagic stroke, narcolepsy or cataplexy, anaphylaxis, acute myocardial infarction, myo/pericarditis, coagulopathy, multisystem inflammatory syndrome, Bell’s palsy, transverse myelitis, appendicitis, pulmonary embolism, and encephalitis. We found an association between vaccination and anaphylaxis (IRR [95% CI]: day 0–17.35 [9.32–30.03], day 1–9.35 [5.12–15.95], day 2–6.20 [3.40–10.57], <20 patients in each risk period). No other outcomes showed significantly increased risk following vaccination. Our results contribute to the safety profile evaluation for XBB.1.5-containing COVID-19 mRNA vaccines utilizing N3C big data. SARS-CoV-2 vaccines containing Omicron subvariant XBB 1.5 were introduced in the United States in 2023. Here, the authors assess the safety of these vaccines by analysing the occurrence of 15 adverse events of special interest following vaccine receipt using electronic health record data.