Inclusion Criteria:  • Active Crohn's disease  Exclusion Criteria:  Active perianal or fistulising disease Pregnant Enteropathy or colitis other than Crohn's disease Symptomatic stricture likely to require surgical treatment Presence of a stoma Presence of an ileoanal pouch Immunodeficiency (beyond that caused by immune suppressants used with IBD) e.g. HIV or Common variable immune deficiency Prednisolone dose >20mg or budesonide dose >6mg Active gastrointestinal infection Alcohol consumption of a dependent nature Primary sclerosing cholangitis Recent overseas travel Contact with COVID-19 positive or DHHS-defined close contact of COVID-19 positive individual in 8 weeks prior to study entry