A 12-month-old girl is evaluated during a routine health maintenance visit. She was diagnosed with DiGeorge syndrome (22q11.2 deletion syndrome) in the neonatal period after presenting with hypocalcemic tetany and a truncus arteriosus, which was surgically repaired at 1 month of age. A recent immunological workup revealed severe thymic hypoplasia with profound T-cell lymphopenia, showing an absolute CD3+ T-lymphocyte count of (normal for age: ). She has no current signs of infection and takes no medications other than daily calcium supplementation. The pediatrician is reviewing her immunization schedule for her 12-month visit. Which of the following immunizations is strictly contraindicated for this patient?
- AHepatitis A
- BPneumococcal conjugate
- Measles, mumps, and rubellaAnswer
- DInactivated influenza
- EHaemophilus influenzae type b
Answer
Measles, mumps, and rubella
The correct answer is the measles, mumps, and rubella (MMR) vaccine. It is a live-attenuated viral vaccine. In patients with severe cellular immunodeficiency, such as this child with profound T-cell lymphopenia secondary to severe DiGeorge syndrome, administration of live vaccines can result in uncontrolled vaccine-strain viral replication and life-threatening disseminated infection. Therefore, it is strictly contraindicated. In contrast, inactivated or subunit vaccines are generally safe to administer, although the immune response may be suboptimal.
Step-by-Step Solution
Key Concept
Live-attenuated vaccines are strictly contraindicated in pediatric patients with severe cellular immunodeficiencies, such as profound T-cell lymphopenia seen in severe DiGeorge syndrome.