Twitter will no longer enforce its policy against COVID-19 misinformation, raising concerns among public health experts and social media researchers that the change could have serious consequences if it discourages vaccination and other efforts to combat the still-spreading virus.

Eagle-eyed users spotted the change Monday night, noting that a one-sentence update had been made to Twitter's online rules: "Effective November 23, 2022, Twitter is no longer enforcing the COVID-19 misleading information policy."

The move also comes amid concerns about Twitter's ability to fight misinformation after it let go of about half of its staff, including those involved in content moderation, under new boss Elon Musk.

At the onset of COVID in 2020, Twitter instated a number of measures including labels and warning messages on tweets with disputed information about the health crisis and a framework to have users remove tweets that advanced harmfully false claims related to vaccines.

Twitter's decision to no longer remove false claims about the safety of COVID-19 vaccines disappointed public health officials, however, who said it could lead to more false claims about the virus, or the safety and effectiveness of vaccines.

(With input from AP, Reuters)