Media outlets have been reporting early-stage development of a Crohn’s disease vaccine.  A phase 1 study to determine the safety and immunogenicity of this vaccine (ChAdOx2 HAV vaccine), which targets a subspecies of Mycobacerium avium, known as Mycobacterium avium paratuberculosis (MAP) has been completed. This study determined that the vaccine was safe for administration in humans. A phase 2 clinical trial involving Crohn’s patients is scheduled to begin, and will progress depending on results. 

Crohn’s disease is a type of inflammatory bowel disease. This chronic disorder has an incidence of approximately 5–15 per 100,000 and a prevalence of 140–200 per 100,00.  The typical age of onset occurs between ages 20-40. Any part of the gastrointestinal (GI) tract, from the mouth to the anus, may be affected by Crohn’s disease. 

Patients with Crohn’s disease may present with symptoms limited to the GI tract, or more generalized manifestations. Patients may report abdominal pain, fever, fatigue, and diarrhea (with or without blood). Patients may also demonstrate findings consistent with malnutrition secondary to malabsorption or profound diarrhea such as unintended weight loss and failure to thrive.  Patients with anorectal disease may present with anorectal fistulas or abscesses.

The most commonly affected areas of the GI tract include the terminal ileum or colon. Patients are typically referred to a gastroenterologist for diagnosis.  A sigmoidoscopy or colonoscopy is typically required for diagnosis.  On colonoscopy, typical findings include a “cobblestone” appearance of affected areas due to thickening of the submucosal tissue. The bowel appears inflamed and ulcerations may be present.  Another characteristic finding of Chron’s disease is the presence of “skip lesions” in the GI tract. This means that the areas of GI tract abnormalities may be discontinuous, which helps to differentiate this diagnosis from ulcerative colitis.

Treatment ranges from supportive care for mild disease to immunosuppressant therapy for severe disease. Patients with very severe disease may require total parenteral nutrition, treatment with glucocorticoids and immunosuppressive agents, highlighting the need for better treatment options.  A complete discussion of treatment regimens is outside the scope of this post. Patients should be referred to a gastroenterologist for determination of severity and choice of treatment regimen.

Harrison’s Manual of Medicine, 19e: Chapter 148: Inflammatory Bowel Diseases

Current Medical Diagnosis & Treatment 2018: Chapter 15: Gastrointestinal Disorders

Current Diagnosis & Treatment: Gastroenterology, Hepatology, & Endoscopy, 3e: Inflammatory Bowel Disease: Medical Considerations

Crohn’s and Colitis Foundation

ClinicalTrials.Gov