hello all. found the board in march when we bought into
DVC but enjoy reading more than posting but i can answer some of the questions. RSV is a virus like the common cold. it causes an upper respiratory infection called bronchiolitis.
the reason it is dangerous for NICU grads is that their lungs are immature and have often gone through prolonged ventilator/oxygen treatment. if an older kid or adult gets it, they rarely get more than a cough or runny nose. But, babies with damaged lungs can have such bad lung inflammation they often require oxygen and sometimes intubation and being put back on a ventilator.
there is no vaccine because the virus changes enough that vaccines do not give adequate immune protection (similar to why there is no vaccine for the common cold or hiv). there is a shot called synagis that is pooled antibodies against the virus however it is very costly (somewhere close to $1000 per vial). it is given to "high risk" babies monthly during peak season (nov.-feb). just like the flu, rsv is only prevalent during rsv season and it would not be cost effective to give it year round. also, like any shot there is a chance of a bad reaction to the immunization. more shots = more chances at a bad reaction, so giving it when there is a very low chance of getting sick is also not "safety effective".
all in all very few babies die from it; however, as the OP's doctor advised if there is no need to put the baby at extra risk of being exposed, then waiting on WDW is the more prudent option. sorry about the trip.