No adverse event; HCP called and reported administration of PROQUAD to a patient while on a possible immunosuppressant. A 4-year-old patient is on Dupixent and received a dose of PROQUAD on 17JAN2025. No additional information was known by reporter. No additional AE/P; This spontaneous report was received from nurse concerns to a 4-year-old patient of unknown gender. The patient’s medical history was not reported. The patient’s concurrent conditions included immunosuppression. Concomitant medications included dupilumab (DUPIXENT). On 17-JAN-2025, the patient was vaccinated with measles, mumps, rubella and varicella (oka-merck) virus vaccine live (PROQUAD) injection, administered for prophylaxis (strength, exact dose, lot #, expiry date, and anatomical route of administration were not provided) to patient while on a possible immunosuppressant (contraindicated product administered). No additional adverse event. Additional information is not expected.