How close do you have to be for baby to catch RSV?

We were in the ER tonight with our 15 month old due to a extremely low temp reading (just a faulty thermometer) anyways, ER was kinda crowded. A women came in with a child with RSV. We tried to keep our distance but she did kinda come near us (3ft) when passing by. Is my son at risk of getting RSV now or does it have to be direct close contact? I’m very paranoid since we were in a ER full of sick coughing children

He is breastfed so he has a little protection