Abstract
BACKGROUND: Vaccine safety is a primary concern among those with a history of adverse reactions to coronavirus disease 2019 (COVID-19) mRNA vaccines. Retrospective data and cohorts of individuals with severe previous reactions suggest that revaccination is safe and well tolerated. However, prospective data are limited. OBJECTIVE: We sought to prospectively assess safety and tolerability of COVID-19 mRNA vaccines in individuals with a history of adverse vaccine reactions and in individuals with long COVID. METHODS: Adults with a self-reported adverse reaction to COVID-19 mRNA vaccination and/or long COVID underwent COVID-19 mRNA revaccination at the University of Michigan with 30-minute observations. Participants were contacted by telephone after 7 days to review interval adverse events. RESULTS: A total of 103 participants received COVID-19 mRNA revaccination-91 with history of adverse vaccine reaction, 20 with long COVID, and 8 with both. Mean age at enrollment was 41.8 years, and women were 67% of the cohort. Five individuals (4.9%) developed immediate symptoms with revaccination. All 5 events were mild (Consortium for Food Allergy Research severity level 1). Vital signs were assessed prevaccination and 30 minutes postvaccination. At 7-day follow-up, 77% of participants reported at least 1 adverse event, with fatigue (33.7%), headache (29.7%), and muscle pain (28.7%) most commonly reported. No follow-up reactions were severe. Five of the 103 participants had incidentally elevated baseline serum tryptase. None of these participants experienced immediate symptoms with revaccination. CONCLUSIONS: Revaccination with COVID-19 mRNA vaccines was safe and well tolerated among individuals with previous adverse COVID-19 mRNA vaccine reaction and/or long COVID.