Prebunking, trying to preemptively protect people before [the] damage occurs, is much more effective than debunking. So what the media described as a psychological vaccine against fake news is really based on the psychological theory of inoculation. So just as injecting yourself with a weakened dose of a virus triggers the production of antibodies to help protect you from future infection you can do the same with information by preemptively injecting people with a severely weakened dose of fake news.

Foundation for Freedom Online

Google Jigsaw's Plan to Vaccinate Your Mind - Foundation for Freedom Online

The censorship industry is working on a new technique: "psychological inoculation," or a "vaccine against disinformation."