Inflammatory Bowel Diseases

Skip Navigation LinksHome > July 2013 - Volume 19 - Issue 8 > Risk of Inflammatory Bowel Disease following Bacille Calmett...
Inflammatory Bowel Diseases:
doi: 10.1097/MIB.0b013e318281f34e
Original Clinical Articles

Risk of Inflammatory Bowel Disease following Bacille Calmette–Guérin and Smallpox Vaccination: A Population-based Danish Case–Cohort Study

Villumsen, Marie MS*,†; Jess, Tine MD, DMSci; Sørup, Signe MS*; Ravn, Henrik MS, PhD*; Sturegård, Erik MD, PhD§; Benn, Christine Stabell MD, DMSci*; Aaby, Peter MDSci*; Roth, Adam MD, PhD*,§

Supplemental Author Material
Collapse Box


Background: Childhood immunology has been suggested to play a role in development of inflammatory bowel disease (IBD) based on the studies of childhood vaccinations, infections, and treatment with antibiotics. Bacille Calmette–Guérin (BCG) and smallpox vaccinations were gradually phased-out in Denmark for children born between 1965 and 1976, hence allowing the study of subsequent risk of Crohn’s disease and ulcerative colitis in a unique prospective design.

Methods: The Copenhagen School Health Records Register contains detailed documentation of vaccination. Among the background cohort of individuals born between 1965 and 1976 (N = 47,622), cases with Crohn’s disease (n = 218) and ulcerative colitis (n = 256) were identified through linkage to the Danish National Patient Registry. The vaccination status of the cases was compared with that of a subcohort (n = 5741) of the background cohort and analyzed in a case–cohort design.

Results: No difference in risk of IBD was observed between individuals vaccinated and unvaccinated with BCG (hazard ratio = 0.95; 95% confidence interval, 0.75–1.19) or smallpox vaccine (hazard ratio = 1.01; 95% confidence interval, 0.77–1.32). This was also the case for Crohn’s disease and ulcerative colitis separately. However, BCG given before 4 months of age may decrease the risk of IBD (hazard ratio = 0.43; 95% confidence interval, 0.20–0.93).

Conclusions: This prospective long-term case–cohort study shows that BCG and smallpox vaccination do not cause IBD later in life. These findings are important for the etiological understanding of IBD and of clinical importance because BCG is still one of the most commonly used childhood vaccinations, smallpox vaccine has been reintroduced in the U.S. military, and both vaccines may be used as vectors in new vaccines.

© Crohn's & Colitis Foundation of America, Inc.

You currently do not have access to this article.

You may need to:

Note: If your society membership provides for full-access to this article, you may need to login on your society’s web site first.


Article Tools


Article Level Metrics

Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.