Which vaccine is associated with febrile seizures in the first two weeks after administration?

Which vaccine is associated with febrile seizures in the first two weeks after administration?

• A. Polio vaccine
• B. DTaP
• C. MMR
• D. Varicella vaccine

Answer: (C)

Febrile seizures after vaccination are most classically seen with vaccines that provoke a robust fever as part of the immune response, and this fever tends to appear in a specific window after dosing. The measles-containing component of the MMR vaccine often produces fever that peaks about 7 to 12 days after vaccination. In a small subset of children, this fever can trigger a febrile seizure within that first two weeks. This timing pattern—fever developing roughly one to two weeks after the shot with a subsequent brief seizure—is the hallmark linking MMR to febrile seizures. Other vaccines can cause fever and occasionally seizures, but their typical timing differs: DTaP-related fever and febrile events usually occur within the first couple of days after vaccination, varicella fever tends to occur earlier (often within a few days), and polio vaccines don’t show the same consistent association in that two-week window. Therefore, the best match for febrile seizures occurring in the first two weeks post-vaccination is the MMR vaccine.

Febrile seizures after vaccination are most classically seen with vaccines that provoke a robust fever as part of the immune response, and this fever tends to appear in a specific window after dosing. The measles-containing component of the MMR vaccine often produces fever that peaks about 7 to 12 days after vaccination. In a small subset of children, this fever can trigger a febrile seizure within that first two weeks. This timing pattern—fever developing roughly one to two weeks after the shot with a subsequent brief seizure—is the hallmark linking MMR to febrile seizures.

Other vaccines can cause fever and occasionally seizures, but their typical timing differs: DTaP-related fever and febrile events usually occur within the first couple of days after vaccination, varicella fever tends to occur earlier (often within a few days), and polio vaccines don’t show the same consistent association in that two-week window. Therefore, the best match for febrile seizures occurring in the first two weeks post-vaccination is the MMR vaccine.