President Joe Biden and Facebook’s tête-à-tête over social media companies’ culpability in spreading false information about vaccines raised familiar questions about protecting online speech while mitigating offline harms. Facebook’s vice president of integrity, Guy Rosen, responded in a blog post and outlined Facebook’s efforts to fight vaccine misinformation Then on Monday, Biden clarified to CNN’s Kaitlan Collins he was referring to the disinformation dozen — a group of 12 prominent anti-vax activists with large social media followings.