and vaccine is shed in the stool so risk of getting it is highest when changing diapers, so wash your hands well with soap then.
The vaccine is administered at 2, 4, and 6 months and each time there is less virus that is shed in the stool. However the risk of adults and older siblings getting the virus is very unlikely. In the rare case you do get it, it will cause a mild diarrhea
Answer assisted by Chethan Sarabu, Medical Student