The company said Monday that it has started using human reviewers to assess whether tweets violate its policy against COVID vaccine misinformation.

Companies including Facebook, Instagram, Twitter, YouTube and Google have all been warning users since at least April that they are experiencing shortages of content moderators, causing a backlog in the removal of harmful posts.

The company said the policy change was not a reaction to the outbreak of the coronavirus, but was part of its continual effort to update its rules against hateful conduct.