Chicken Pox Party Can A Child Spread Chicken Pox By Getting On A Water Slide With Other Children @ A B-day Party?

Can a child spread chicken pox by getting on a water slide with other children @ a b-day party? - chicken pox party

It is my cousins B-1 days, but our cousins has chickenpox, if you get in the gutter with the other children that other children are also infected, too? If you can not receive the vaccine against chickenpox are still infected with chickenpox?