Background: 22q11.2 Deletion Syndrome (22q11.2DS) can result in array of congenital abnormalities including immune dysfunction. International guidelines recommend immune evaluation of 22q11.2DS patients prior to live vaccine administration. A rotavirus vaccination program for infants aged 2 and 4 months was implemented in British Columbia (BC) in 2012. Adherence to immune workup recommendations prior to 2 months of age in patients with 22q11.2DS and adverse events following immunization is not known.

Methods: A retrospective chart review of children diagnosed with 22q11.2DS in BC from January 1, 2012 to January 1, 2019 was conducted. Demographic, clinical, laboratory, immunization data and adverse reactions to vaccines were obtained. International guidelines were used as a reference for adherence to immunologic workup recommendations.

Results: Forty-two children with 22q11.2DS were included. Immunization records were available for 39 children, and 22 (52.3%) received at least one dose of a live rotavirus vaccine. No adverse events following immunization were noted in clinical records. While 25 out of 27 (92.6%) of patients who received an immunological workup had a CD4 + lymphocyte count to qualify for safe administration of a live vaccination, only 12 (44%) received the Rotavirus vaccine. Of 22 infants diagnosed with 22q11.DS prior to 8 weeks of age, only ten (45.5%) received an immune workup before the rotavirus vaccine.

Conclusions: The majority of our infant cohort did not receive medical care consistent with international 22q11.2DS vaccination and immunological surveillance recommendations. More effective dissemination of 22q11.2DS guidelines and improved immunological assessment for infants with 22q11.2DS in BC is necessary.