A 15-month-old child presents with fever and ear ache 12 days after receiving MMR vaccine. Physical examination reveals acute otitis media. The MOST likely explanation for this fever is:
- A Vaccine-induced measles encephalitis
- B Vaccine-associated fever from MMR is expected 7–14 days post-vaccination; this is an intercurrent infection coinciding with that period ✓
- C Mumps vaccine component causing parotitis and otitis
- D MMR vaccine failure with wild-type measles infection
Correct answer: B. Vaccine-associated fever from MMR is expected 7–14 days post-vaccination; this is an intercurrent infection coinciding with that period
Explanation
MMR vaccine commonly causes a low-grade fever with or without a mild morbilliform rash 7–12 days post-vaccination, reflecting transient replication of the attenuated measles virus strain. This is a known, expected vaccine effect. However, otitis media with a high fever is an intercurrent bacterial infection that happens to coincide temporally with the MMR fever window rather than being caused by it. Clinicians must distinguish expected vaccine reactions from coincidental infections occurring in the same period.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.