Development of immediate and chronic spontaneous urticaria following mRNA COVID-19 vaccination: Tolerability of revaccination and immunological study

Coronavirus 2019 (COVID-19) vaccination remains one of the key public health measures against the SARS-CoV-2 infection, significantly reducing illness severity and mortality rates. Urticaria and/or angioedema are cutaneous reactions that have been reported in response to messenger RNA (mRNA) COVID-19 vaccination and potentially affect fitness for revaccination.1 The development of chronic spontaneous urticaria (CSU) post-COVID-19 vaccination2 may further discourage patients from revaccination or preclude revaccination to keep vaccinations updated. We describe a Singapore case series of 64 patients with urticaria post-COVID-19 vaccination, studying patient tolerance to revaccination, immunological profile and development of CSU.