Newborn plus toddler in daycare

We will be having our second daughter in about a month. My toddler starts a preschool this summer twice a week. Babe should be less than a month when toddler goes to school. I'm really worried about my newborn cathing something. My toddler has been in another daycare up until now. Typically gets a cold every now and then but she's just caught rsv. I'm so worried about her to begin with and now I'm scared for my newborn who will be born soon too. Any tips?!