Bassinet/car seat cover - please help me

Hey moms

So, I live in New York City where I rely heavily on the public transportation to travel anywhere. I recently gave birth to my son last week and he’s now one week old. His immune system is still brand new and fragile. My main concern about take him out on a train for his doctor appointment or WIC appointment and have him exposed to sickness. I can’t use cabs all the times - it’s a lot of money. So, will that cover for the car seat/bassinet help protect my son from get sick? Thank you!