Rapid onset of chronic urticaria after Moderna COVID-19 booster vaccine

Abstract

A substantial number of patients with newly onset of chronic urticaria was observed rapidly after the booster vaccine against COVID-19. This observation was unprecedented compared to the primary series of vaccination. To address this concern, we initiated an online observational study with the help of local allergists. We found a striking association between the booster dose, the Moderna vaccine, and the new onset of chronic urticaria within the following 10 days. These data were confirmed when reviewing all cases of CSU related to COVID-19 vaccination reported to Swissmedic, the Swiss regulatory agency. These data should not discourage patients from being vaccinated, as this vaccination campaign has been instrumental in reducing COVID-19 burden and preventing millions of deaths. Yet, there is an urgent need to establish appropriate guidelines and monitor this adverse event more closely, considering that a fourth dose is currently being administered.