Multisystem Inflammatory Syndrome after Ad26.COV2.S vaccination.

Background: The multisystem inflammatory syndrome (MIS) is a rare and sometime life-threatening post-infectious complication of coronavirus disease 2019 (Covid-19) in children and adults. To date, only a very few reports have associated such systemic reaction with SARS-CoV-2 vaccination.

Case Report: we describe a case that resembled MIS, in a 46-year-old White man, 12 days after vaccination with Ad26. COV2. S vaccine (Johnson &Johnson/Janssen), a recombinant adenovirus serotype 26 vector encoding the SARS-CoV-2 spike glycoprotein. The patient experienced high grade fever, cutaneous rash, severe weakness, pericardial effusion and raised inflammatory markers, which met the criteria for definition of MIS. The symptoms improved with steroidal therapy.

Conclusions: Our case suggests that MIS could occur after SARS-CoV-2 vaccination.