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Difficulty: MediumImmunizations and Vaccine-Preventable Diseases

A 14-month-old boy is brought to the clinic for a health maintenance visit. He missed his 12-month checkup due to a prolonged hospitalization for severe abdominal pain and bloody diarrhea, which led to a diagnosis of very early-onset inflammatory bowel disease. He was initiated on infliximab therapy three weeks ago, and his parents report an excellent clinical response. He has no other medical problems and takes no other medications. Vital signs are within normal limits. Growth curves show him at the 15th percentile for weight and 40th percentile for length. Physical examination reveals a well-appearing child with a soft, non-tender abdomen. His immunization record shows he received all age-appropriate vaccines at 2, 4, and 6 months of age. The physician plans to update his immunizations today. Which of the following vaccines should be omitted from his schedule at this time?

  1. A
    Hepatitis A vaccine
  2. B
    Pneumococcal conjugate vaccine
  3. Measles, mumps, and rubella vaccineAnswer
  4. D
    Haemophilus influenzae type b vaccine
  5. E
    Intramuscular influenza vaccine

Answer

Measles, mumps, and rubella vaccine
The correct answer is the measles, mumps, and rubella vaccine. Infliximab is a tumor necrosis factor (TNF)-alpha inhibitor that causes significant systemic immunosuppression. The administration of live-attenuated vaccines, such as the measles, mumps, and rubella (MMR) vaccine, is strictly contraindicated in patients receiving systemic immunosuppressive therapies. This contraindication exists because immunocompromised individuals lack the robust cellular immunity required to control the attenuated virus, putting them at high risk for uncontrolled viral replication and severe, disseminated infection. Therefore, the MMR vaccine must be omitted until the patient has discontinued the immunosuppressive medication and completed an appropriate washout period.

Step-by-Step Solution

1
Identify the patient's immune status based on his current medications.
The patient is taking infliximab, a tumor necrosis factor (TNF)-alpha inhibitor, which induces significant systemic immunosuppression.
Recognizing medically induced immunosuppression is critical for determining the safety profile of various vaccines.
2
Recall the general rules for vaccinating immunocompromised pediatric patients.
Live-attenuated vaccines are strictly contraindicated due to the risk of disseminated disease. Inactivated and conjugate vaccines are safe and recommended.
Immunocompromised hosts cannot mount a sufficient cellular immune response to safely control and clear live vaccine strains.
3
Classify the given vaccine options to identify the live-attenuated formulation.
The measles, mumps, and rubella vaccine is live-attenuated. The Hepatitis A, Pneumococcal conjugate, Haemophilus influenzae type b, and Intramuscular influenza vaccines are all inactivated or subunit vaccines.
This classification directly isolates the one vaccine that must be omitted from today's visit.

Key Concept

Live-attenuated vaccines (e.g., MMR, varicella) are strictly contraindicated in patients receiving severe immunosuppressive therapies, such as biologic TNF-alpha inhibitors, due to the risk of disseminated infection.
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Topics

Immunizations and Vaccine-Preventable Diseases

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