[gitaarik]

It actually has two similar statements in the policy:

    - False or misleading information regarding the safety or science behind approved or authorized COVID-19 vaccines, such as:
      - The vaccines will cause you to be sick, spread the virus, or would be more harmful than getting COVID-19. 
      [...]
      - False or misleading claims that people who have received the vaccine can spread or shed the virus (or symptoms, or immunity) to unvaccinated people.

https://help.twitter.com/en/rules-and-policies/medical-misin...

So there's both a "can" and a "cause".