For months, public health experts — backed by guidelines from the World Health Organization and the Centers for Disease Control and Prevention — have stood firm on one resounding refrain: Against the coronavirus, masks work.
But on Saturday, Dr. Scott Atlas, one of President Trump’s most prominent science advisers, took to Twitter to say otherwise.
“Masks work? NO: LA, Miami, Hawaii, Alabama, France, Phlippnes, UK, Spain, Israel,” Dr. Atlas tweeted, rattling off a list of locations where masks had, in his view, failed to protect large swaths of the population.
Not long after, Dr. Atlas reshared his first tweet with a message that seemed to walk back his original statement: “Use masks for their intended purpose — when close to others especially hi risk,” he said. “Otherwise, social distance. No widespread mandates.”
On Sunday, Twitter removed Dr. Atlas’s first tweet, saying it violated the company’s policy against false or misleading information about the coronavirus that could lead to harm.
But the damage had already been done: The post had been retweeted at least 1,800 times, and generated over 7,300 likes and replies. The removal then set off a flurry of anti-mask posts, and accusations of tech censorship, across social media. On Facebook, several right-wing pages shared copies of the tweet, while a series of anti-mask and pro-Trump groups and pages claimed that Twitter was suppressing free speech.
Dr. Atlas, a radiologist with no background in infectious disease or public health, has come under heavy fire in recent months for his stances on the coronavirus, which has killed more than 219,000 Americans. Experts have widely dismissed and criticized his views on lockdowns and masking mandates after he has derided them as unnecessary and even harmful in the fight to halt the pandemic.
Dr. Atlas has also promoted the controversial idea that herd immunity — the point at which a virus can no longer spread easily because enough people have contracted it — can be reached when only a small sliver of the community at large has been infected.
In his now-defunct Saturday tweet about masks, Dr. Atlas cast doubt on their usefulness, saying there was little evidence that they reduce disease transmission. As a send-off, he shared a link to an indictment of face coverings published on Friday by the American Institute for Economic Research, a libertarian think tank that recently sponsored a declaration arguing that the coronavirus should be allowed to spread among young healthy people to expedite herd immunity.
Masks, like all other protective measures, cannot halt the coronavirus on their own. But experts consider the accessories a crucial part of the public health tool kit needed to combat the pandemic, alongside tactics such as physical distancing and widely available testing.