Chickenpox vaccine...how long to wait after possible exposure??

[Emsillyh]

Hello all, first post here after using this site for my late night answers for many years!! I decided that I would vaccinate my son against chickenpox, if he'd not had it by age 6. My son has autism (with high sensory needs, touch sense is super heightened). His friend at school came out with chickenpox and we were told by the teacher, that was 19 days ago. In between then and now, he caught threadworms (yuck!!) which was basically torture for him with the itching, it was soul destroying. So I've decided to vaccinate asap. BUT there's not much point if he's going to come out with it. How long should I wait? I keep reading 14 days maximum, then read some posts saying 21 days. Could I therefore book him in for day 22?! Thank you oh wise mummies!

Forgot to say he's 5!

DD1 had terrible pox that was infected and very very unwell, and I quickly changed my mind about the whole ‘it’s a mild childhood disease’. So I booked DD2 in for the first available appointment. She had the vaccine 7 days after first exposure. The doctor said if it has a week in her system to start working then she should only get it mild.
She was right. DD2 got a few spots another week lately. She probably had 12/13 spots in total, the tiniest blisters, and wasn’t unwell at all. Her spots came and went within a few days while DD1 was still covered in scabs 3 weeks later.
I would say to book it day 22 as usually pox appears within 21 days.

I'd do it asap. My DC were exposed at nursery, I got them vaccinated about 2 weeks later and one DC got one spot, other didn't develop it at all.