Songfacts®:

• Here, Matt Bellamy reflects on how other people's thoughts, ideas and beliefs can sometimes infect your mind and end up changing the way you think yourself. The Muse frontman explained to Rolling Stone his inspiration was "probably watching American news stations." Bellamy added:
  
  "We're living in an age where these sort of ideologies, people's belief systems, whether they are true or false, are getting a lot of air time, especially ones on the false side. I think that we're living in an unusual period where a lot of airtime is being given to crazy ideas. The flip side is that we're living in a time where pointing out someone's inaccuracies, using science for example, is becoming increasingly difficult. Sometimes it's even perceived as an insensitive thing to do.
  
  The verses are me streaming off anxieties and feelings, which in the course of the song, I'm wondering whether they're actually mine or not. I don't know to what extent I'm influenced by others. Sometimes your anxieties about the world or your anxieties about the world of the future can be lessened by turning the news off and turning your phone off for a few days. You then realize that everything is fine."
• You've been bitten by a true believer
  You've been bitten by someone who's hungrier than you
  You've been bitten by a true believer
  You've been bitten by someone's false beliefs
  
  Bellamy explained that the above represent the song's key lines. He said: "That summarizes what I'm trying to get at here, which is sometimes in life you will come across situations where someone who is a bit ideological or believes things that are not true in any way will sometimes have more power than you, over you or get more airtime. I think that's really what the song is about. It's about how other people's false belief systems can infect your own and sometimes even affect your feelings."
• When pressed for the meaning behind the track during Matt Wilkinson's Beats 1 show, Matt Bellamy explained: "The clue is in the title, 'Thought Contagion'. I first heard about it from a Richard Dawkins book years ago actually, it's this idea that thoughts are contagious – they spread like a virus, or like genes."
  
  He continued: "If you spend a few hours watching American news, well, that's were the first part of the song came from really. It's kinda like some strange bubble where they're all living up Trump's bum, basically… It gets inside your mind. I think that's where the song came from really. You start walking round worrying about things that you wouldn't normally think about and so the song came from that. How other people's ideas can kinda take over your own if you're not careful."
• Speaking at the VO5 NME Awards 2018, Bellamy told NME that the song has "an arena sound."
  
  "We're getting into blending genres and eras together, both in the styles and in the music", he said. "It's an arena sound and synths. There's a couple of synths in it. It's a pretty epic and anthemic track."