Almost thirty years earlier (Episode 114), Mister Rogers also visited the doctor to show what it's like to get an injection.
The doctor Mister Rogers visits is located at the Center City Health Center in Pittsburgh, PA.
Mr. Rogers does not put on his sweater until after he gets his immunization this is the second time Mr. Rogers is out of his sweater for most of the episode.
Dr. Forbes mentions that the influenza immunization is not admistered orally however there is a nasal spray option for influenza in lieu of an injection.