Does nursery exclusion period apply to siblings too?

I've tried messaging the nursery but just waiting on a response and wondering what the general etiquette is. My younger son( 11 and half months) has just started in the same nursery as my 3 yo and I've just got back to work. On Wednesday the 3yo threw up after his tea- they both spend Thursdays at home; obviously I won't be sending the 3yo back tomorrow (on Friday) as they have a 48 hour exclusion but I'm wondering whether to send baby in. They both haven't had any symptoms at all and have been their usual selves. Would make things easier to send baby in as it means missing less work plus he's been settling really well. But completely understand if the polite thing to do is keep the both at home.