April 07, 2014
By Will Boggs MD
NEW YORK - Live vaccines may be safe for individuals with mild to moderate immunosuppression related to DiGeorge syndrome, according to a retrospective study.
DiGeorge syndrome, a chromosome 22q11.2 microdeletion that occurs in 1:3000 to 1:6000 births, is associated with varying degrees of immunosuppression. These individuals face increased risk of recurrent and/or prolonged infections from vaccine-preventable infections, but live vaccines are generally contraindicated except in some patients with partial DiGeorge syndrome.
Dr. Philip LaRussa from Columbia University, New York and colleagues in the Clinical Immunization Safety Assessment (CISA) Network describe live-vaccine preventable illnesses, vaccination patterns, and adverse events following live immunization among 194 individuals with a documented chromosome 22q11.2 microdeletion.
Patients ranged in age between 0 and 31.5 years, and the mean observational period was 8.3 years.
Fourteen individuals experienced a live vaccine-preventable illness (11 varicella infections, three rotavirus infections), according to a report online March 31st in Pediatrics.
All individuals had received at least one vaccine, and 90% had received at least one live vaccine. More than half (58%) completed the recommended 4:3:1:3:3:1 vaccination series by age 19 to 35 months. (The Centers for Disease Controls defines the series here: http://1.usa.gov/1hxDG5M).
Just over a quarter (27%) received a live vaccine before confirmation of their diagnosis, and early confirmation was associated with lower MMR and varicella vaccination coverage and delayed timeliness.
There were 91 adverse effects in 44 live-vaccine recipients, resulting in 72 outpatient sick days, 13 emergency department visits, and six hospitalizations, but no deaths.
The events occurred after 14% of MMR vaccines, 20% of varicella vaccines, 8% of oral polio vaccine, and 5% of rotavirus doses. There were no differences in adverse events by age, gender, race, ethnicity, cardiac disease, or cardiac surgery.
Adverse event rates did not differ by CD4 percentage, and only one of three individuals with CD4% below 15% before live vaccination experienced an adverse event following live-vaccine immunization.
"Prospective studies are needed to confirm our findings and offer guidance for live vaccination, as done previously for individuals with HIV given varicella vaccine," the researchers conclude. "Lymphocyte screening before all live immunizations should be encouraged because our data indicate that this is not universally done and that the level of immunodeficiency varies over time in individual patients with DiGeorge syndrome."
They acknowledge that their study included few patients with severe immunosuppression.
Dr. Ivan K. Chinn from Duke University, Durham, North Carolina has published several studies related to DiGeorge syndrome and its treatment. He told Reuters Health by email, "Most children with DiGeorge anomaly do not have such significant T cell deficiency that severe complications after live viral immunizations would be expected. The goal, however, should be to find a way to capture the few for whom live viral immunizations would not be safe."
"Lymphocyte enumeration should absolutely be performed as a screening method prior to giving live viral immunizations to children with DiGeorge anomaly," Dr. Chinn said.
He warns that T cell counts and phenotypes can change over time in infants with this condition.
"Thus, combined with the findings in this article, it may be best to perform lymphocyte enumeration at 12 months of age and then give the MMR and varicella immunizations to all patients who do not have severe CD4+ T cell lymphopenia," Dr. Chinn said. "The children who have severe immunodeficiency should then have lymphocyte enumeration performed at later points in time to see if the CD4+ T cell counts improve sufficiently enough to allow for future immunization with live viral vaccines."
Dr. LaRussa did not respond to a request for comments.
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