Introduction:

Vaccine-associated autoimmunity is a well-known phenomenon attributed to either the cross-reactivity between antigens or the effect of adjuvant. The reactogenicity of COVID-19 mRNA vaccine in individuals suffering from immune-mediated diseases has not been investigated. We would like to present a case of Crohn’s disease flare up after receiving COVID-19 Pfizer vaccine.

Case description/methods:

33 years old male with history of Crohn’s Disease (CD) complicated by fistula formation s/p Right hemicolectomy with ileocolic anastomosis in 2014 was admitted due to abdominal pain, diarrhea and rectal bleeding for 2 days. Patient reported he did not have any CD symptoms and was off maintenance medications therapy for 1.5 years. He had first dose of COVID Pfizer vaccine 2 days before his symptoms have started. Physical examination was significant for tenderness in RLQ, vitals were stable and patient afebrile. A laboratory work up was significant for elevated ESR (22), iron deficient anemia, B12 deficiency, hypophosphatemia and hypomagnesemia. Stool studies were negative for signs of infection Abdominal and Pelvic CT scan with contrast shown stable enlarged mesenteric lymph nodes and no signs of acute inflamatory process.Colonoscopy showed Rutgeerts score i1 and no evidence of of colonic CD involvement. Colonoscopy also revealed active inflammation, ulceration and adenomatous change at ileocolic anastomosis. Patient was consulted with Gastroenterology and treated with Prednisone 40 mg, IV Iron, B12 and electrolytes with rapid improvement of patient’s symptoms.

Discussion:

During the past decades, there has been growing awareness of possible adverse events associated with vaccinations. When coming to COVID-19 vaccine, it is further complicated by the nucleic acid formulation and the accelerated development process imposed by the emergency pandemic situation. Currently formulated mRNA vaccines coding for the SARS-CoV-2 full-length spike protein have shown the highest level of evidence according to the efficacy and safety profile in clinical trials. Although the results from phase I and II/III studies have not raised serious safety concerns, patients with underlying immune-mediated disease were not specifically studied. mRNA vaccines may give rise to a cascade of immunological events eventually leading to the aberrant activation of the innate and acquired immune system that can be potentially associated with exacerbation of conditions involving dysregulated immune responses such as Crohn’s disease.