• Key idea: All mothers have previous exposure to chickenpox and should theoretically have protective IgG that they can pass to their newborns
• Key idea: Only time newborn should receive prophylactic VZV immunoglobulin is if mother developed chickenpox rash <5 days before delivery, mother developed chickenpox rash <2 days after delivery or if baby were born to a non-immune mother and was exposed to somebody with chickenpox

https://step-prep.org/tutoring/

"I think there's no intervention necessary here. Newborns should have mom's antibodies. Related. Pay attention to the first bullet point, its a testable concept." reddit.com/r/medicalschool/nbme_7step_2_5_questions/

Well, I found a Uworld explanation that recommends something that seems to contradict this: "postexposure prophylaxis is indicated for newborns born to mothers with varicella developing 5 days before to 2 days after delivery. Prophylaxis is achieved by administering varicella-specific immunoglobulin to the infants, who are too young to receive live varicella-zoster virus vaccine"

The only thing I can think is that one is coming from the mother vs coming from another kid... doesn't seem like that should matter though.

One might approach this question also by taking into account that children receive MMRV at 12mo & 4 years of age...child is 4 years old and therefore adequately vaccinated therefore no intervention necessary.

Otherwise, if he 3 years old, probably would get VZV vaccine.