“When tweets include misleading information about Covid-19, we may place a label on those tweets that includes corrective information about that claim,” the website notes in a section detailing its rules about Covid-19 misinformation. “We may apply labels to tweets that contain, for example … false or misleading claims that people who have received the vaccine can spread or shed the virus (or symptoms, or immunity) to unvaccinated people.” Users can receive penalties up to a permanent ban.

The change was made on Dec. 2, according to Wayback Machine archives retrieved by Reclaim the Net. The policy contradicts the Centers for Disease Control and Prevention guidance, which notes the “risk for SARS-CoV-2 infection in fully vaccinated people cannot be completely eliminated as long as there is continued community transmission of the virus.”