It's called "Believing the first thing you hear or read on the Internet, and automatically rejecting everything you hear or read on the subject after that." It just means that some loony anti-vaxxer got to him/her first.
There ought to be a formal name for the fallacy of assigning greater credibility to earlier information, but I'm not sure what it would be.
There ought to be a formal name for the fallacy of assigning greater credibility to earlier information, but I'm not sure what it would be.