This is not a fail-safe mechanism, but marks the most creditable work put out in the various disciplines. Scientists and doctors deliver papers at conferences which generate news. These are not peer-reviewed but usually conference organizers have asked the individual to give the paper because he or she is a recognized expert in the field. That give some backing but not much. Science by press conference is to be viewed warily.
Cold fusion is a perfect example of bogus science by press conference.
No story should be run on press conference science without additional reporting, i.e., contacting credible scientists in the field for their reaction. If that cannot be done because of either time or staff constraints, consider spiking the story. Controlled clinical studies. This is the best stuff. In this type of study, one test group gets a particular treatment and another control group does not.