AAANND, if they said nothing, and some thing horrible happens, some untrained commenter/reporter/radio host would say "the CDC doesn't know anything, they did not warn us this might happen".
Pick what you want, a medical community that tells you what CAN happen, or that tells you what you want to hear. The doctors I deal with (numerous specialties, pediatric and adult, in America), are in the "list everything that CAN happen" mindset. They try to add the probabilities of an outcome, and point out what the most likely outcome is. They have to, or some ambulance chaser lawyer will "help" a patient sue them for "not warning them" of a potential outcome. If you talk with the doctor, and they are candid, they readily admit it can be hard to predict medical outcomes, because human beings and medical facilities have so many variables it is amazing we survive at all.
My wife hates that, because she is a pessimist, and dwells on the low probability "worst case".