P486 Immunization status of children and adolescents with inflammatory bowel disease or autoimmune hepatitis in Germany

Background: Long-term immunosuppressed patients with inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH) are at risk of severe infections with vaccination preventable diseases. Several recent studies demonstrated insufficient immunization coverage in children and adolescents with IBD. Therefore, we evaluated the vaccination rate of children and adolescents with IBD and AIH in Germany. Methods: As part of the German multicentre clinical trial called “VARICED”, the immunization rate of patients with IBD and AIH below 18 years of age was assessed from the certificate of vaccination, medical history of chicken pox and by analysing varicella zoster virus (VZV) IgG and measles virus IgG antibody titres by ELISA. Results: To date 229 patients (51% female, mean age at diagnosis 9.9 years) are registered: 137 have Crohn's disease (CD), 53 ulcerative colitis (UC), 19 IBD-unclassified (IBD-U) and 20 AIH. The majority of the patients (n=190, 83%) are on immunosuppressive therapy (AIH 100%, CD 89%, UC 68%). A complete basic immunisation consisting of 4 doses of a hexavalent vaccine were given to 89% of the total cohort. A combined inoculation for measles, mumps, and rubella (MMR) was documented in 225 (98%) patients, 208 (92%) received two doses. VZV vaccination was introduced in 2004 to the vaccination schedule from the German Standing Committee on Vaccination (STIKO). A good implementation with 90% was found in the birth cohorts from 2005 onwards. In children born before 2005 (n=190) only 22% received VZV vaccination catch up. VZV vaccination was documented in only 77 (34%) patients, but 17 patients (22%) did not display sufficient VZV IgG titres. Already 144 (63%) patients had a medical history of chicken pox. However, three of them did not have verifiable VZV IgG antibodies. In addition, 37 patients had neither a history of a chicken pox infection nor VZV inoculation, but 11 out of them were found to have sufficient VZV IgG titres. Conclusions: There is a good implementation of the vaccination schedule from the German Standing Committee on Vaccination (STIKO) in the group of children and adolescents with IBD and AIH. Our data suggests a gap in VZV immunity in birth cohorts before 2005 in Germany. Moreover, neither the certificate of vaccination nor the medical history of chicken pox infection is reliable for assessing VZV immunity. Serologic investigations demonstrated that some non-immunized patients may undergo occult immunization, and immunized patients did not present sufficient VZV-IgG titres. Thus, we recommend VZV IgG serology within the check-up in newly diagnosed IBD or AIH and VZV vaccination before initiating immunosuppressive therapy, if applicable.