Study says influenza immunization is safe in children with IBD

Influenza immunization rates in children with inflammatory bowel disease (IBD) are low despite its safety according to a new study by researchers at the Institute for Clinical Evaluative Sciences (ICES), Children's Hospital of Eastern Ontario (CHEO), the Ottawa Hospital Research Institute (OHRI), and the University of Ottawa.

Yearly influenza immunization is recommended in patients with IBD, including sub-types of Crohn's disease and ulcerative colitis. However, concern about vaccine-related adverse events may limit uptake. Given that Ontario has the highest rates of childhood-onset IBD in the world, and offers universal influenza immunizations to everyone more than six months old, this locale offers the optimal setting to evaluate rare outcomes in children with IBD, such as adverse events following immunization.

"While influenza immunization rates in children with IBD are low, immunization did not result in increased adverse events or contacts with the health system," says Dr. Eric Benchimol, lead author, adjunct scientist at ICES, and principal investigator at the CHEO Research Institute.

The study examined all children under 19-years-old diagnosed with IBD, in Ontario between 1999 to 2009 and matched them to non-IBD controls, and found:

25.3 per cent of IBD patients received immunization from a physician or nurse practitioner.

No increased adverse event rates existed in IBD cases after receiving the immunization, compared to control periods.

IBD-related visit rates were lower after receiving the immunization compared to control periods.

"There is no risk of IBD flare following influenza immunization. In fact, in the years they were immunized, children with IBD had lower rates of IBD-related outpatient physician visits compared to years they were not immunized. This may indicate that receiving the influenza vaccine protects against having a flare of IBD, or at least prevents visits to doctors for IBD-related symptoms," says Benchimol.

The researchers add no increase in health services use for IBD-related concerns in the post-vaccine risk period in IBD patients, and evidence of a protective effect of influenza immunization against IBD-related health services use should encourage improvement of poor coverage rates.

The study "Safety and utilization of influenza immunization in children with inflammatory bowel disease," was published today in Pediatrics.