Facebook froze as anti-vaccine comments swarmed users

FILE- In this April 10, 2018, file photo, Facebook CEO Mark Zuckerberg testifies before a joint hearing of the Commerce and Judiciary Committees on Capitol Hill in Washington. Last spring, as false claims about vaccine safety threatened to undermine the world's response to COVID-19, researchers at Facebook wrote that they could reduce vaccine misinformation by tweaking how vaccine posts show up on users' newsfeeds, or by turning off comments entirely. Yet despite internal documents showing these changes worked, Facebook was slow to take action. (AP Photo/Alex Brandon, File)

FILE - In this Sept. 23, 2021, file photo, Oumie Nyassi shows a video circulating on the internet and that has been confirmed as fake news of a woman claiming she was magnetized after receiving the COVID-19 vaccine, in a doctor's office at Serrekunda, Gambia hospital. Last spring, as false claims about vaccine safety threatened to undermine the world's response to COVID-19, researchers at Facebook wrote that they could reduce vaccine misinformation by tweaking how vaccine posts show up on users' newsfeeds, or by turning off comments entirely. Yet despite internal documents showing these changes worked, Facebook was slow to take action. (AP Photo/Leo Correa, File)

WASHINGTON — In March, as claims about the dangers and ineffectiveness of coronavirus vaccines spun across social media and undermined attempts to stop the spread of the virus, some Facebook employees thought they had found a way to help.