ABSTRACT
In response to the COVID-19 pandemic, two mRNA vaccines (Comirnaty and Spikevax) received emergency use authorization from the European Medicines Agency. This case report aimed to report a delayed adverse reaction to the mRNA-1273 vaccine against COVID-19 from a Portuguese vaccination center.A case report was performed with medical observation and reported to the Portuguese Pharmacovigilance System, then investigated based on the WHO-UMC Causality Categories. A 66-year-old female patient with a clinical history of dyslipidemia, essential arterial hypertension, obesity, multinodular goitre and cholecystectomy, who presented delayed large cutaneous hypersensitivity reaction following Spikevax COVID-19 mRNA (mRNA-1273) vaccine administration.Our clinical findings (time and clinical appearance), along with evidence of previously reported histological findings, are strongly suggestive of T-cell-mediated hypersensitivity. There is no contraindication to the inoculation of subsequent doses in patients developing these clinical conditions, and vaccination should continue to be strongly encouraged.