Serologic Protection to and Completion Of Vaccinations In Children With Inflammatory Bowel Disease

Abstract

BACKGROUND: In children with inflammatory bowel disease [IBD], data on serologic protection to vaccines along with adherence to vaccination schedules is limited. The study objectives were to determine the proportion of children with IBD with serologic protection to vaccines and evaluate adherence to vaccination schedules. METHODS: In this single-center cross-sectional study, children with IBD followed at the Alberta Children's Hospital were enrolled (September 2011-August 2012). Demographic data, IBD medication, infection risk factors, and vaccination records were collected. Serum was collected and analyzed by the Provincial Laboratory of Public Health. Serologic protection for rubella and hepatitis B virus (HBV) were defined by titers of IgG ≥15 IU/mL and antibody to HBV surface antigen ≥10 IU/ L, respectively. Serologic protection for hepatitis A virus (HAV) was defined by positive detection of HAV IgG. Serology results for varicella, measles, mumps, tetanus, and diphtheria are pending. From vaccination records, the proportion with complete series for each vaccine according to the Alberta schedule was evaluated. RESULTS: In total, 156 children (93 Crohn's disease, 47 ulcerative colitis, 16 IBDunclassified) completed the study and underwent serum collection; vaccine records were available for 152. At enrolment, 93 subjects (60%) were using immunosuppressive medications (20 systemic corticosteroids, 70 immunomodulators, 48 biologics); an additional 32 subjects had previously used immunosuppressive medications. For HBV (administered at 10 years of age), though 115 subjects completed the series, 33 (29%) lacked serologic protection. Twenty-five (16%) subjects received no (n = 14) or incomplete (n = 11) vaccine not accounted for by young age. In total, 57 (37%) subjects lacked serologic protection to HBV; potential risk factors in this naive subgroup included history of travel outside of Canada (n = 49), blood transfusion (n = 8), and body piercing (n = 15). There was no association between HBV serologic protection or completion of vaccine series and any current or past immunosuppressive medication use. For measlesmumps- rubella, though 140 subjects completed the series, 26 (18.6%) lacked serologic protection to rubella, including 15 subjects currently using immunosuppressive medications. Ten subjects received no or incomplete vaccine series not accounted for by young age. There was no association between rubella serologic protection and any current or past use of immunosuppressive medications. For varicella zoster virus (VZV), 60 subjects received ≥1 VZV vaccine dose and 83 non-vaccinated subjects had previously been infected with chickenpox. However 10 (6.5%) subjects had neither been infected nor vaccinated, including 7 subjects currently using immunosuppressive medications. For diphtheria-pertussis-tetanuspolio- haemophilus influenza b, though 131 subjects were up to date for age, 23 subjects received no or incomplete series not accounted for by young age. For HAV, 9 subjects received complete HAV series and all mounted serologic protection. Though 137 subjects had no prior history of HAV vaccination, 22 of these subjects mounted serologic protection. In total, 32 (20.5%) subjects had serologic protection to HAV. CONCLUSION(S): Children with IBD are at risk for vaccine-preventable illnesses due to lack of receiving or completing vaccine series and inadequate serologic protection despite vaccination. Therefore, clinicians caring for patients with IBD should be conscientious about vaccination schedule adherence, serology measurement, and booster vaccinations where appropriate.