A 15-month-old child received varicella vaccine yesterday at a private clinic. Today the mother brings him for his pending MMR dose. What is the CORRECT action?
- A Give MMR after an interval of at least 4 weeks ✓
- B Give MMR today at a different site
- C Give MMR after an interval of 8 weeks
- D Withhold MMR permanently and substitute with measles monovalent vaccine
Correct answer: A. Give MMR after an interval of at least 4 weeks
Explanation
Two live parenteral vaccines not administered on the same day must be separated by at least 4 weeks. If given closer than this, the immune response to the second vaccine is blunted, so the MMR given yesterday-plus-a-few-days would be invalid and would need repeating. There is no requirement for an 8-week gap, and substituting monovalent measles has no immunological advantage. Giving both live vaccines simultaneously at separate sites would have been perfectly acceptable.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.