Doctors are like car mechanics. They can diagnose issues faster than I can most of the time, and you need them to "fix things" you cannot fix at home. But don't expect the car mechanic to understand the fully physics of the engine, or how his diagnostics tool works. Similar, the doctor doesn't know the biochemical workings of his drugs or how a virus exactly spreads. And last, just as the car mechanic gets training from the car manufacturer, the doctor gets told what is true/right by the medical community. He or she doesn't really deviate from these told doctrines.

So always do your own research.