People on immunosuppression therapies require timely access to the second dose of COVID-19 vaccines

COVID-19 vaccination

Research raises questions over safety of delaying the second vaccine dose

The COVID-19 & IBD Task Force calls on the National Advisory Committee on Immunization (NACI) to include IBD patients on immunosuppression therapies on the list of exceptions for extended dosing intervals. Provincial Ministries of Health should allow IBD patients to have the second dose of their vaccine at the time indicated on vaccine labels (as indicated by the manufacturers).  

Crohn’s disease and ulcerative colitis, the most common forms of inflammatory bowel disease (IBD), are chronic diseases where the body's immune system attacks mostly the bowel, causing a number of debilitating symptoms.

“People living with inflammatory bowel disease often require regular treatments to manage a number of excruciating symptoms and bring their disease under control,” says Dr. Eric Benchimol, a pediatric gastroenterologist at The Hospital for Sick Children as well as Chair of Crohn’s and Colitis Canada’s Scientific and Medical Advisory Council. “We use medications that suppress the immune system to get patients into remission. However, this has become much more complicated in the context of the pandemic.” 

In March 2020, Crohn’s and Colitis Canada formed the COVID-19 & IBD Task Force, led by Dr. Benchimol and Dr. Gil Kaplan, gastroenterologist and Professor of Medicine at the University of Calgary, along with infectious diseases and IBD experts, patient representatives, and community leaders. The Task Force meets regularly to compile evidence-based guidelines and advice designed to “keep people living with IBD safe and their disease under control during the pandemic.” 

The Task Force cites the results of the CLARITY IBD study from the UK for people living with IBD. The study provides substantial biologic plausibility that individuals with IBD on immunosuppression therapies (such as azathioprine, methotrexate and biologics like infliximab) should receive their second vaccine dose as indicated in the manufacturer’s randomized clinical trials (3 weeks after the first dose for the Pfizer mRNA vaccine; 4 weeks after the first dose for the Moderna mRNA vaccine and Oxford-AstraZeneca adenovirus-vector vaccine).
In short, people with IBD on immunosuppression therapies have a much lower antibody response and may be less protected after one dose of the vaccine. 

The Crohn's and Colitis Canada COVID-19 & IBD Task Force recommends:

  • People with IBD should be vaccinated against COVID-19;
  • People with IBD who are using immunosuppression therapy should not delay the second dose of their COVID-19 vaccine beyond the time recommended by the manufacturers;
  • People with IBD who have received one dose of a COVID-19 vaccine (Pfizer, Moderna, or AstraZeneca) should consider themselves susceptible to COVID-19; and 
  • While COVID-19 vaccines continue to be studied, those with IBD, regardless of vaccination, should practice physical distancing, wear a mask, use good hand hygiene, and follow the recommendations of the COVID-19 & IBD Task Force and local public health authorities.

To learn more about the COVID-19 & IBD, visit

  • Canada has among the highest incidence rates of Crohn's and colitis in the world.
  • 1 in 140 Canadians lives with Crohn’s or colitis.
  • Families new to Canada are developing these diseases for the first time.
  • Incidence of Crohn’s in Canadian kids under 10 has doubled since 1995.
  • People are most commonly diagnosed before age 30.

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