Real-time analysis of a mass vaccination effort confirms the safety of FDA-authorized mRNA COVID-19 vaccines

McMurry, Reid; Lenehan, Patrick; Awasthi, Samir; Silvert, Eli; Puranik, Arjun; Pawlowski, Colin; Venkatakrishnan, A. J.; Anand, Praveen; Agarwal, Vineet; O’Horo, John C.; Gores, Gregory J.; Williams, Amy W.; Badley, Andrew D.; Halamka, John; Virk, Abinash; Swift, Melanie D.; Carlson, Katie; Doddahonnaiah, Deeksha; Metzger, Anna; Kayal, Nikhil; Berner, Gabi; Ramudu, Eshwan; Carpenter, Corinne; Wagner, Tyler; Rajasekharan, Ajit; Soundararajan, Venky

Background As the COVID-19 vaccination campaign unfolds, it is important to continuously assess the real world safety of FDA-authorized vaccines. Curation of large-scale electronic health records (EHRs) enables near real-time safety evaluations that were not previously possible. Methods In this retrospective study, we deployed deep neural networks over a large EHR system to automatically curate the adverse effects mentioned by physicians in over 1.2 million clinical notes between December 1st 2020 and April 20th 2021. We compared notes from 68,266 individuals who received at least one dose of BNT162b2 (n = 51,795) or mRNA-1273 (n = 16,471) to notes from 68,266 unvaccinated individuals who were matched by demographic, geographic, and clinical features. Findings Individuals vaccinated with BNT162b2 or mRNA-1273 had a higher rate of return to the clinic, but not the emergency department, after both doses compared to unvaccinated controls. The most frequently documented adverse effects within 7 days of each vaccine dose included myalgia, headache, and fatigue, but the rates of EHR documentation for each side effect were remarkably low compared to those derived from active solicitation during clinical trials. Severe events including anaphylaxis, facial paralysis, and cerebral venous sinus thrombosis were rare and occurred at similar frequencies in vaccinated and unvaccinated individuals. Conclusions This analysis of vaccine-related adverse effects from over 1.2 million EHR notes of more than 130,000 individuals reaffirms the safety and tolerability of the FDA-authorized mRNA COVID-19 vaccines in practice.