Give the MMR Vaccine Now
This 18-month-old child with a fever of 38.9°C (102°F) and congested throat should receive the MMR vaccine as scheduled, without postponement. 1, 2
Rationale Based on Current Guidelines
The Advisory Committee on Immunization Practices (ACIP) explicitly states that minor illnesses with or without fever are not contraindications to vaccination. 1, 2 This clinical scenario—a child with fever around 102°F and congested throat who appears only slightly ill—qualifies as a minor illness, not a moderate-to-severe acute illness. 2
Key Supporting Evidence
Seroconversion rates are equivalent: Children with mild febrile illness achieve similar antibody responses to MMR vaccine as healthy children, with more than 97% developing appropriate protective antibodies. 1, 2
Vaccination should not be postponed for upper respiratory infections or low-grade fever according to ACIP guidelines. 2
Moderate-to-severe illness is the threshold for deferral, defined as symptoms that significantly affect daily functioning—not simply the presence of fever or congestion. 1, 2
Clinical Decision Framework
Proceed with vaccination if:
- The child has mild symptoms (congestion, cough, fever) but is feeding normally and not significantly impaired in daily activities 1
- The child appears generally well despite symptoms 1
- This describes your patient—slightly ill with fever and congestion but functioning adequately 2
Defer vaccination only if:
- The child has moderate-to-severe acute illness significantly affecting daily functioning 1
- This prevents confusing vaccine adverse effects with progression of the underlying illness 2
Critical Practical Considerations
Every opportunity to vaccinate must be utilized, especially when follow-up compliance cannot be assured. 1, 2
Delaying vaccination for minor symptoms leads to incomplete vaccination series, missed opportunities, and increased vulnerability to vaccine-preventable diseases. 1
Routine temperature measurement is not even a prerequisite for vaccination in apparently healthy infants. 1
Common Pitfall to Avoid
Do not confuse post-vaccination fever and rash (which can occur 5-14 days after MMR) with contraindications to giving the vaccine during minor illness. 3 The decision to vaccinate is based on current illness severity, not concern about post-vaccination symptoms.
Answer: A - Give MMR now