Optimising immunisations in children with 22q11 microdeletion

Abstract

Background: 22q11 microdeletion syndrome has a broad phenotypic spectrum including immune disorders. The majority of patients with 22q11 microdeletion have a mild to moderate immunodeficiency leading to an increased susceptibility to infections3. As a result, immunisation is an important preventative disease measure in this cohort of patients. Live vaccines are often delayed due to safety concerns and there are currently no established guidelines regarding immunological testing prior to live vaccine administration. Queensland Children's Hospital Child Development Unit, based in Brisbane, cares for the majority of children with 22q11 microdeletion in Queensland. Here we describe the immunisation profiles of this cohort of children and our proposed immunological investigation pathway prior to live vaccine administration. Aim: To describe the immunisation profiles of this cohort of children and our proposed immunological investigation pathway prior to live vaccine administration. Methods: Retrospective review of medical, pathology and immunisation records of all children with 22q11 microdeletion under the care of the Child Development Unit at Queensland Children's Hospital between 2000 to 2018. Data captured included: current vaccination status, immunology work up proceeding live vaccine administration, adverse events following immunisation (AEFI) and the proportion of children who have appropriately received additional pneumococcal immunisation. Results: There were 134 patients over the study period, age range between 0-18 years. 124 individuals were eligible for live vaccinations: 82% had completed MMR dose 1, 77% had completed MMR dose 2 and 66% had completed varicella immunisation. There were no AEFI notifications in this cohort of patients. 18% of patients received medical at risk dose of prevenar 7 or 13 and 16% received their pneumovax 23 from 4 years of age. Following revision and implementation of Medical At Risk Immunisation Guideline in August 2018, 40% received their medical at risk doses of prevenar 7 or 13 and 31% completed their pneumovax 23 from 4 years of age. Immunology work up practices were demonstrated to vary widely prior to live vaccine administration. An immunological investigation and vaccination pathway was therefore developed. Most patients' immune profiles were consistent with mild to moderate immunodeficiency. Conclusion: Our study supports the findings of studies to date that live vaccination can be safely administered in patients with 22q11 microdeletion despite evidence of mild to moderate immunosuppression5. Further studies are required to support guidelines for immunology investigation and guidance for live vaccinations in this cohort of patients.L6279140412019-06-06 <br />