Live vaccines are generally contraindicated in patients with DiGeorge syndrome (DGS), a congenital disorder characterized by cellular immune deficiency. Vaccine utilization and safety in this population are not well described. This study examined vaccination patterns and adverse events following live immunization (AEFLI) in these individuals.
A multicenter retrospective cohort study was conducted in subjects with DGS confirmed by fluorescence in situ hybridization assay (chromosome 22q11.2 microdeletion). Live vaccine-preventable illnesses, vaccination coverage and timeliness, and AEFLIs in the 56-day window after live vaccination were examined. Bivariate and multivariable analyses assessed the impact of demographics medical history, timing of diagnostic confirmation, and preceding immune function on vaccination patterns and AEFLIs.
Of 194 subjects, 77% and 75% received measles-mumps-rubella (MMR) and varicella vaccines, respectively; 58% completed recommended vaccinations by age 19 to 35 months. Adverse events occurred after 14% and 20% of MMR and varicella vaccine doses, respectively. Most events were minor, few were serious, and no deaths were reported in post–live vaccination windows. Although early diagnostic confirmation negatively affected live vaccination coverage and timeliness (P < .001), baseline CD4% did not differ between subjects who did or did not receive live vaccines by 12 to 18 months. Among varicella vaccine recipients, those with a subsequent adverse event had a lower preceding CD4% (24.8% ± 7.3%) than those without (35.5% ± 11.7%) (P < .05); no CD4% differences were observed with MMR vaccination. Fourteen unvaccinated subjects experienced live vaccine–preventable illnesses.
Live vaccines were frequently given and generally well-tolerated among patients with DGS with mild-to-moderate immunosuppression.
Comments
Live vaccine use and safety in DiGeorge syndrome revisited
This is a wonderful study on live vaccine safety in a large immune deficient population. While overall useful and larger than any previous study, there are two points worth making.
1) Since all patients had a chromosome 22q11.2 deletion, it is preferable to use that terminology to distinguish this cohort from subjects who have the phenotype of DiGeorge syndrome due to any one of a number of causes.
2) The overall vaccine safety was high, as has been previously reported, but it is extremely important to reiterate that live viral vaccines are still contraindicated in settings of profound immune deficiency. This cohort had mild to moderate decrements in CD4, as defined by the percent of CD4 cells. While the sample size was the largest to date, it was not large enough to capture a significant number of children with profound immune deficiency. Therefore a caution is in order. CD4% is not the optimal filter as CD4 counts are more likely to reflect the intactness of the T cell compartment. Each child should have an immunologic evaluation prior to live viral vaccine administration and those with significantly compromised immunity, CD4 counts <400 in two prior studies, should be counseled regarding the risks and benefits specifically for their situation. No child with absent T cells should receive ANY live viral vaccination and should be treated as a SCID patient.
Conflict of Interest:
None declared