This is a summary, written by members of the CITF Secretariat, of:

Kuenzig ME, Widdifield J, Bernatsky S, Kaplan GG, Benchimol EI. Uptake of third doses of SARS-CoV-2 vaccines among people with inflammatory bowel disease in Ontario, Canada. The Lancet Gastroenterology & Hepatology. 2022 Feb 23. DOI:

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

In this short correspondence published in The Lancet Gastroenterology and Hepatology, CITF-funded researchers Dr. Jessica Widdifield of the University of Toronto, Dr. Sasha Bernatsky of McGill University, and colleagues presented the frequency of SARS-CoV-2 vaccination in Ontario patients with inflammatory bowel disease (IBD). Among 107,059 patients identified with IBD, 89.9% had one dose, 88.6% had two doses, and 58.3% had three doses as of January 9, 2022.

Using health administrative data, researchers identified all patients with IBD, aged 18 years or older, living in Ontario as of September 1, 2021, and compared their vaccination status to people without IBD. A total of 107,059 patients with IBD were identified and more than 12 million individuals without IBD were included.

Key findings:

  • 9% of patients with IBD had one dose of a SARS-CoV-2 vaccine, 88.6% had two doses, and 58.3% had three doses.
  • By comparison, 85.6% of people without IBD had one dose, 83.8% had two doses, and 44.3% had three doses.
  • Among individuals with IBD, those between 18 and 39 years of age were least likely to receive a third dose. Notwithstanding that, this group had higher uptake of third doses compared to the same age group in the general population.

People with IBD are potentially at high risk of contracting and developing severe COVID-19 disease due to their prolonged use of immunosuppressant medications. As has been shown in this study and others, people with IBD are more likely to get vaccinated than the general population. However, the percentage of vaccinated people is still suboptimal. Identifying why people with IBD may be hesitant to receive third vaccine doses is especially important given their particular vulnerability.