With ‘Cure’ Comment, Trump Exaggerates Known Benefits of Another Covid-19 Therapy

That number broke the president’s previous weekly record of 25 million interactions, which came in November 2016, the week he was elected. (Mr. Trump’s highest single-day total was on Election Day that year, when he received 12.3 million interactions.)

The president’s most-engaged post came on Saturday, the day after he was flown to Walter Reed National Military Medical Center. It was Mr. Trump’s first appearance on social media after his hospitalization, and he claimed his treatment was “going well, I think!” The post received more than three million interactions.

A post by Mr. Trump two days later, in which he told his followers, “don’t be afraid of Covid,” got more than 1.5 million interactions. The post was widely criticized by medical experts for downplaying the risks of the virus, and critics called for it to be taken down from Facebook and Twitter. But neither company took it down, saying it did not pose an immediate threat of physical harm.

Facebook did take down another of the president’s posts, in which he falsely claimed that Covid-19 was less lethal than the flu. Twitter left the same post up, but covered it with a warning that it violated the company’s rules on Covid-19 misinformation.

Mr. Trump responded to that takedown by calling for the repeal of Section 230 of the Communications Decency Act, a law that shields internet platforms from some lawsuits. The president has repeatedly claimed that Facebook and other social networks are biased against conservatives, despite evidence that right-wing content is some of the highest-performing material on the platforms.

Engagement data doesn’t capture how widely posts are seen in users’ feeds, or whether the reactions to them are positive or negative. But most of the responses to Mr. Trump’s posts appeared to be from well-wishers and people hoping for a speedy recovery. Of the 2.5 million interactions on his Saturday post saying his treatment was “going well,” nearly all were accompanied by the “like,” “heart” or “hug” emoji. (Only 1,200 people reacted with the frowny-face emoji.)

Mr. Trump has been one of Facebook’s most popular accounts for years. But in the months leading up to the election, the engagement on his page has been growing, allowing him to circumvent the mainstream media and turning him into a major broadcaster in his own right. Last month, the president received 87 million Facebook interactions — more than CNN, ABC News, NBC News, The New York Times, The Washington Post and BuzzFeed combined.

Joe Biden, Mr. Trump’s Democratic challenger, also had one of his best-ever weeks of Facebook engagement, with 4.7 million interactions — less than one-fifth of Mr. Trump’s total.

“From a scientific standpoint, it makes it extremely hard to figure out what benefit came from which of the three medications,” Dr. Bell said.

Medical experts were also quick to point out that Mr. Trump’s touting of the treatment was at least the third time this year that the president has exaggerated the benefits of an unapproved Covid-19 therapy. He had previously promoted hydroxychloroquine and convalescent plasma, and on Wednesday advocated making the antibody treatment “free” for anyone who needed it.

Hydroxychloroquine, a malaria drug that researchers attempted to repurpose for use in people with the coronavirus, was repeatedly championed — and taken — by Mr. Trump, despite a lack of evidence that it worked. After granting emergency authorization for use of hydroxychloroquine, the Food and Drug Administration revoked it, citing studies showing that the drug did not help Covid-19 patients and could cause serious side effects in some.

Convalescent plasma is the antibody-rich portion of blood donated by people who have recovered from Covid-19. Mr. Trump pressured the F.D.A. to give the treatment emergency approval in August, even though there was no strong evidence that it benefited sick patients.

Dr. Megan Ranney, an emergency medicine physician at Brown University, said that the endless cycle of talking up new treatments — many of which might not pan out — could erode public trust in science and medicine.

“It’s like the boy who cried wolf,” she said. “It’s going to make it more difficult to get the real changers.”

Experts think monoclonal antibodies, like the cocktail taken by Mr. Trump, could fare better than hydroxychloroquine and convalescent plasma.

The treatment is “super promising, and all of us are excited from a theoretical perspective,” Dr. Ranney said. “But it’s just too early,” she added, to tell if theory will translate into practice.

Monoclonal antibodies are synthetic, mass-produced mimics of the molecules the human body produces in response to an infection. Some antibodies are powerful enough to block the coronavirus from infiltrating cells. Administered to people battling the coronavirus, the monoclonal antibodies could help naturally produced immune molecules fend off the virus.

Just days before Mr. Trump tested positive for the coronavirus and was admitted to the hospital, Regeneron announced a batch of preliminary results, collected from ongoing trials, via news release. They suggested Regeneron’s monoclonal antibody cocktail could tamp down the amount of virus found in the nasal cavity, and hasten recovery in people who had contracted the virus but hadn’t been hospitalized.

On Wednesday evening, Regeneron announced it was seeking an emergency approval from the F.D.A. for its antibody cocktail.

The data so far for monoclonal antibodies looks “very promising,” said Dr. Phyllis Tien, an infectious disease physician at the University of California, San Francisco. But it’s crucial, she added, to let the trials run to completion to fully assess safety and efficacy. Unanticipated side effects could crop up, or the treatment might not perform as well in certain people as it does in others.

Mr. Trump’s allusions to making monoclonal antibodies “free” for widespread use are also probably off base. Monoclonal antibodies are expensive and difficult to produce in large quantities. Regeneron estimated that it would initially have enough doses for only 50,000 people, though the company plans to scale up production in coming months.

What’s cheaper, Dr. Ranney said, are the many preventive strategies available to keep the virus from infecting people in the first place, such as masks and physical distancing: “How about we focus on that?”

After the ban, QAnon believers began to speculate on Twitter and other social media platforms that Facebook’s move was a sign that the moment they had predicted — Mr. Trump reveals his long fight with satanic pedophiles — had finally arrived.

One tweet, which was liked nearly 1,000 times, linked to an announcement by the Justice Department of a news conference Wednesday morning on a matter of “national security.” The tweet claimed the Justice Department was preparing charges against a number of senior Democrats, including Hillary Clinton.

Similar tweets by QAnon believers said the news conference would have even bigger news, including an appearance by Mr. Trump to announce that he had arrested hundreds of members of a shadowy group that QAnon believers falsely claim are secretly running a satanic cabal. Many of those tweets were also shared and liked hundreds of times.

The Justice Department’s news conference on Wednesday detailed the investigation and arrest of several members of the Islamic State terrorist organization. There was no mention of the satanic cabal that QAnon followers claim Mr. Trump is battling.

But after the conference ended, QAnon adherents still maintained the Justice Department would deliver on the sprawling conspiracy theory that their members have spun over years.

Researchers who study QAnon said it was typical of the group to incorporate new conspiracies into their narrative to account for inaccurate predictions. Travis View, a host of “QAnon Anonymous,” a podcast that seeks to explain the movement, said the group was already rallying around the idea that a surprise was coming in October or November.

Conspiracy theories, Mr. View said, have a way of continuing to live on, even after being repeatedly proven false.

But his comparisons of Covid-19 and the flu stand in sharp contrast to months of data gathered by experts, who have repeatedly said that the coronavirus poses a far more serious threat than influenza viruses. Based on data gathered thus far, most flu viruses are less deadly and less contagious than the coronavirus. And while flu vaccines and federally approved treatments for the flu exist, no such products have been fully cleared by governing bodies for use against the coronavirus.

Twitter appended a note to Mr. Trump’s tweet, saying that it violated the company’s rules about spreading false and misleading information about the virus. But it kept the post up, saying that it was in the public interest to keep it accessible. Facebook removed a similar post from Mr. Trump, saying that the company removes incorrect information about the coronavirus.

According to the Centers for Disease Control and Prevention, between 24,000 and 62,000 flu-related deaths occur in the United States each year — substantially fewer than Mr. Trump claimed. In February, Mr. Trump stuck closer to the facts at a White House news conference. “The flu, in our country, kills from 25,000 people to 69,000 people a year. That was shocking to me,” he said at the time. Earlier that month, according to the recent book by Bob Woodward, Mr. Trump described the coronavirus as “more deadly than even your strenuous flus.” On average, seasonal flu strains kill about 0.1 percent of the people they infect.

The coronavirus, on the other hand, has killed more than 210,000 people in the United States, and more than one million worldwide, since the start of 2020. The virus’s true mortality rate remains unclear, as it is difficult to gather such data while the pandemic rages on. Inadequate testing has also made it hard to pinpoint how many people have been stricken by the virus, which can spread silently from people who never show symptoms.

Still, estimates from experts tend to put the coronavirus’s death rate higher than the flu’s. The virus’s death toll was especially high in late winter and spring, when hospitals were overwhelmed, clinically tested treatments were scarce and masking and distancing were even more scarce than they are now.

“This is basically nonsensical ranting and raving,” Angela Rasmussen, a virologist at Columbia University, said about Mr. Trump’s statements. “This just demonstrates that, for a businessman, President Trump doesn’t seem to have much of a grasp of mathematics.”

Frequent encounters with past flu strains, in combination with effective vaccines, can also bolster the body’s defenses against new flu viruses. The coronavirus, however, has swept through a defenseless population of unprepared hosts at a dizzying rate.

Deaths also don’t reveal the entire picture. Researchers still don’t fully understand the long-term consequences of coronavirus infections, which have saddled a growing number of people, called long-haulers, with serious and debilitating symptoms that can linger for weeks or months.

Medical experts have also warned that as the northern hemisphere cools for winter, the flu and Covid-19 could collide, fueling a new spate of deaths.

Mr. Trump, who tested positive for the coronavirus last week, has downplayed the severity of the pathogen several times in recent days, even though he was sent to Walter Reed National Military Medical Center to receive treatment for Covid-19. While at the hospital, he received several therapies typically designated only for those who are very seriously ill.

Medical experts immediately took issue with the post. More than 200,000 Americans have died from the virus, and more than 35 million cases have been reported around the world. Dr. Bob Wachter, the chair of the department of medicine at the University of California, San Francisco, said Mr. Trump’s tweet was “breathtakingly callous, inhumane & counterproductive.” Dr. Bernard P. Chang of Columbia University’s department of emergency medicine warned that people should remain afraid of the virus.

But Facebook and Twitter did nothing about Mr. Trump’s post, even though the companies have publicized their coronavirus misinformation policies.

Facebook has said it does not allow coronavirus posts that can lead to direct physical harm, and will redirect people to a Covid-19 information center. Twitter also removes only posts that contain demonstrably false information with the “highest likelihood of leading to physical harm.”

For Facebook and Twitter, these details matter. They are paying close attention to whether or not Mr. Trump is giving a specific direction or command to engage in an activity that could immediately put people in danger. When he suggested in April that experts look into whether people could inject disinfectant to fight off the coronavirus, Facebook and Twitter used the same yardstick and took no action to remove clips and posts about the unproven treatment.

Mr. Trump and his director of social media, Dan Scavino, have hewed closely to the line of what is allowed on various social media accounts over the past four years, seemingly pushing the envelope as far as possible without inciting the tech companies to take punitive action.

Facebook did not respond to a request for comment. A Twitter spokesman said the tweet did not violate the company’s rules since it did not include a clear call to action that could potentially cause real-world harm.

By Monday evening, Mr. Trump’s tweet and Facebook post on Covid-19 had been viewed by more than one million people across both networks. Mr. Trump later posted a video reiterating that people should not let the virus dominate their lives. “Get out there,” he said. “The vaccines are coming momentarily.”

The Gateway Pundit, a website notorious for regularly spreading misinformation and falsehoods, published an article calling Mr. Trump’s drive-by to greet fans a “miracle in Maryland.”

“I believe in miracles,” said another tweet on Sunday afternoon, after Mr. Trump’s doctor said he could return to the White House as early as Monday. “We are going to see another one in November!”

Others reposted and repeated Mr. Trump’s own words in a video he released on Saturday that his hospitalization and process of recovery constituted a “miracle from God coming down.”

Alex Plitsas, the vice chairman of the Fairfield Republican Town Committee in Connecticut and a onetime contributor to the conservative news and opinion site The Daily Caller, said the people criticizing Mr. Trump’s trip past supporters on Sunday were hypocritical. He said that they advocated wearing masks to stop the spread of the virus, but that when Mr. Trump wore one they said that was not enough to please them.

The Centers for Disease Control and Prevention and the World Health Organization say face coverings are a safeguard but not an absolute guarantee of stopping transmission — especially in a small, sealed space like a vehicle occupied by a person known to be infected, as was the case on Sunday.

Mr. Plitsas did not immediately respond to a request for comment.

Greg Price, another contributor to The Daily Caller, said the Secret Service agents accompanying Mr. Trump during the drive-by had always been at risk because they have been around the president during his bout of illness.

“The point of my tweet was that the safety of the agents didn’t become a big story until President Trump did the drive by,” Mr. Price said in a direct message on Monday.

Dr. James Phillips, an attending physician at Walter Reed, said the specific situation of being in a sealed vehicle increased the agents’ risk. “Presidential SUV is not only bulletproof, but hermetically sealed against chemical attack,” he tweeted. He added that the risk of Covid-19 transmission was “as high as it gets outside of medical procedures.”

The C.D.C. says cloth face coverings help prevent the person wearing the mask from spreading Covid-19 to others, but it doesn’t say wearing a mask fully prevents the spread of the virus. The drive angered some members of the Secret Service, The Washington Post reported.

“Many of the statements that are being pushed by Trump’s supporters have been debunked by medical experts, but at this time, no one is being rational,” said Claire Wardle, executive director of First Draft, an organization that fights online disinformation. “These tweets and the online conversation is not about science or expertise, it’s about emotions and partisanship.”

Over the weekend, other Twitter users also posted that Mr. Trump should use hydroxychloroquine, with some calling it a “miracle drug.” The hashtag #hydroxychloroquine popped up frequently on Twitter, with others posting under the hashtag #HCQWORKS.

All of the online activity means it’s a good time to sort through what we know about hydroxychloroquine.

The drug has long been used to treat malaria, lupus and rheumatoid arthritis. At the start of the pandemic, a handful of small, poorly designed studies suggested that it could block the coronavirus from replicating in cells.

Since then, the data on hydroxychloroquine’s effectiveness against the virus has been mixed. The early, seemingly promising results, bolstered by political pressure, prompted the Food and Drug Administration to grant the drug an emergency authorization for use in very sick Covid-19 patients. Follow-up studies, however, found the drug neither sped recovery nor prevented healthy people from contracting the coronavirus or progressing to serious disease.

The F.D.A. ultimately revoked its emergency approval. The agency now warns that hydroxychloroquine can cause dangerous abnormalities in heart rhythm in coronavirus patients. Researchers have also conducted large reviews concluding that hydroxychloroquine does not benefit Covid-19 patients, and have reaffirmed the risks of side effects in these individuals.

Still, the drug has been championed by some — including President Trump, who praised it through the summer.

So what treatment is Mr. Trump, who has been hospitalized at Walter Reed military hospital, actually receiving?

His doctor, Sean P. Conley, has said Mr. Trump had received an infusion of an experimental antibody treatment developed by drug maker Regeneron, and was also taking zinc, vitamin D, melatonin, aspirin and a generic version of the heartburn treatment Pepcid. Dr. Conley has also said the president has begun a five-day course of remdesivir, an antiviral drug given emergency use authorization from the F.D.A. to treat hospitalized Covid-19 patients. And on Sunday, Dr. Conley said Mr. Trump had been given the steroid dexamethasone, which has been shown to help patients who are severely ill with Covid-19 but can be harmful for patients with mild or moderate cases of the disease.

Hydroxychloroquine was not mentioned by Mr. Trump’s medical team. That prompted some on Twitter to speak out on what they saw as an omission in his treatment.

1. The New York Times: Trump’s Taxes Show Chronic Losses and Years of Income Tax Avoidance (5,730,782 interactions)

The Times’s big scoop about Mr. Trump’s taxes led the pack this week, with more than five million interactions, making it the paper’s most-engaged article of the year.

2. Fox News: Trump announces Amy Coney Barrett as nominee for Supreme Court seat (1,315,885 interactions)

3. The Daily Wire: Chris Wallace Faces Intense Backlash, Including From Colleagues, Over Bias During Debate (1,176,793 interactions)

Right-wing websites like The Daily Wire took aim at Mr. Wallace after Tuesday’s debate. This article, which aggregated tweets from right-wing commentators, struck a nerve among Trump supporters who felt that the president had been unfairly treated by the Fox News anchor.

4. Fox News: Trump $500B Black America plan designates KKK, Antifa as ‘terrorist organizations’ (1,169,050 interactions)

Another Fox News story, this one about President Trump’s recent announcement that he would propose designating the Ku Klux Klan and antifa “terrorist organizations.” (Legal experts have said that the proposal is largely symbolic, and that there was no legal authority for labeling a domestic group this way.)

5. NBC News: Proud Boys say they are ‘standing down and standing by’ after Trump’s debate callout (1,156,849 interactions)

After Mr. Trump told the Proud Boys, a far-right extremist group, to “stand back and stand by” during Tuesday’s debate, the group’s supporters adopted the president’s remarks as a rallying cry. (Note: NBC’s original headline misstated Mr. Trump’s comment.)

6. The Washington Post: The pandemic pushes hundreds of millions of people toward starvation and poverty (1,054,643 interactions)

UNICEF was the top sharer of this Washington Post analysis, which concluded that when it comes to the economic toll of the coronavirus pandemic, “the gloom is only deepening.” (Note: UNICEF’s Facebook posts receive an additional boost from the platform’s Covid-19 info panels.)

7. The Blaze: President Trump tweets that he and the first lady have tested positive for coronavirus (891,140 interactions)

8. CNN: New York Times: Trump paid no income taxes in 10 of past 15 years (825,737 interactions)

9. The Daily Wire: John Legend: I Might Leave America If Trump Remains President. Uh-Huh. Legend Just Bought $17.5M Beverly Hills Mansion. (804,617 interactions)

Days before Mr. Legend and his wife, Chrissy Teigen, announced that they had lost their child after pregnancy complications, The Daily Wire got more than 800,000 interactions on an article calling attention to Mr. Legend’s saying that he would consider leaving America if Mr. Trump were re-elected.

10. Variety: BTS: See Every Variety Cover (795,837 interactions)

The 10th most-engaged story of the week was a roundup of magazine covers featuring BTS, the K-pop supergroup. Never underestimate a K-pop supergroup.

The tweets questioning Mr. Trump’s announcement peaked at five per minute on Friday morning according to Dataminr, a social media monitoring service. The doubters included Jelani Cobb, a staff writer at The New Yorker, and Anand Giridharadas, editor at large of Time and an occasional contributor to The New York Times.

Some suggested that the announcement from the president could be an excuse to delay the election, since he is trailing in the polls, and cancel future presidential debates.

Some of the people doubting Mr. Trump said they couldn’t believe him because of how much false and misleading information he has spread about the virus in the past.

Researchers at Cornell University published a study this week showing that Mr. Trump was the single largest driver of false and misleading information about the coronavirus. Mentions of Mr. Trump made up nearly 38 percent of the overall “misinformation conversation,” the researchers said.

Mr. Trump has also stated on at least 34 separate occasions since February that the coronavirus would go away.

“We’re in an environment where conspiracies are thriving, in part because the president encourages them,” said Melissa Ryan, chief executive of Card Strategies, a consulting firm that researches disinformation. “And we have a White House comms operation that gives the press and public disinformation constantly.”

The situation has created “the perfect storm for people to assume that the White House isn’t being truthful,” Ms. Ryan said.

Many of the deniers also latched on to a tweet from Sept. 18 that had originally been shared in conspiracy circles, but was reshared widely on Facebook and Twitter after Mr. Trump’s announcement on Friday. “Trump’s October surprise will be the announcement of ‘his infection,’” it said. “Fake, but quite dramatic.” The post collected nearly 15,000 interactions across Facebook and Twitter, mostly from people who falsely asserted that Mr. Trump catching the virus was a known plan.

And some saw people’s reactions to the announcement as a reflection of the sheer magnitude of misinformation that has emanated from the president.

Another meme, shared by the conservative influencers the Hodgetwins, depicted Mr. Wallace as Mr. Biden’s knight in shining armor.

Other conservatives tried to paint Mr. Wallace as a Trump hater in disguise, pointing out that he is a registered Democrat. This is true. Mr. Wallace has described himself as “independent,” and has said he registered as a Democrat because “where I live, in Washington, D.C., the only elections that count are the Democratic primaries.”

But other claims about Mr. Wallace were not true, such as a rumor that circulated on WeChat, the Chinese messaging app, that claimed he was “fired” from moderating any future debates. Some users also shared an image that was falsely labeled as showing Mr. Wallace with Jeffrey Epstein, the financier and accused sex trafficker. (The photo actually showed Mr. Wallace with the actor George Clooney, a vocal liberal with whom he is friendly.)

The right-wing attacks have not stopped at Mr. Wallace. Conservatives have also begun casting doubts about the fairness of the second presidential debate, which is scheduled for Oct. 15 and is slated to be moderated by Steve Scully, a longtime C-SPAN political editor and host.

One right-wing meme accused Mr. Scully of being connected to the “deep state.” Other conservatives referred to him as a former Biden intern, or said he and Mr. Biden had gone to college together. (They did not go to college together, although Mr. Scully did intern with Mr. Biden’s Senate office while an undergraduate at American University. He also was an intern for Senator Edward M. Kennedy.)

Senator Ted Cruz, Republican of Texas, called the choice of moderator “NUTS,” and proposed having future debates moderated by teams of one Republican and one Democrat.

Pro-Trump partisans also began digging for evidence that the Commission on Presidential Debates, the bipartisan organization that sponsors the debates, was biased against Mr. Trump. Mr. Trump has complained about the commission in the past, calling it “very biased” and saying it is “stacked with Trump Haters & Never Trumpers.” (The group’s leadership consists of both Democrats and Republicans.)

Those claims have been renewed after Tuesday’s debate. On Thursday, supporters of QAnon, the pro-Trump conspiracy theory, began posting unfounded rumors about members of the debate commission, and pointing out that President Barack Obama is an honorary co-chair. (He is, as are former presidents from both parties, including George W. Bush.) Q, the pseudonymous message board poster whose posts fuel the theory, also weighed in, calling the commission’s choice of Mr. Scully as a debate moderator evidence of a “rigged system.”

Death threats and other harassing messages have since poured into Mr. Malinowski’s office in Washington. In an interview on Wednesday, he called the threats “a direct result” of the advertisement, noting that the calls his office had received cited its central accusation.

“We’ve been warning the Republicans running this play for at least the last two or three weeks that they were playing with fire,” he said. “Now the match has been lit.”

The threats against Mr. Malinowski were earlier reported by BuzzFeed News.

QAnon, the New York Times columnist Kevin Roose has explained, is the umbrella term for a sprawling set of internet conspiracy theories that claim, falsely, that the world is run by a group of Satan-worshiping pedophiles who are plotting against Mr. Trump while operating a global child sex-trafficking ring. The F.B.I. has warned that QAnon poses a potential domestic terrorism threat.

The attack ad against Mr. Malinowski played directly to the group’s chief charge.

“In every city, in every neighborhood, around every corner, sex offenders are living among us,” the narrator of the ad intoned.

“Tom Malinowski chose sex offenders over your family,” the ad said.

A separate document circulated by Republican officials repeated the claim, specifically stating that Mr. Malinowski “worked to ensure sex offenders who violated children” would not have to join the registry.

Mr. Malinowski, a former State Department official in the Obama administration, has said he did not work on that bill — a statement corroborated by Human Rights Watch — and that his portfolio at the organization was focused on foreign policy matters.

But the campaign arm doubled down on its claim on Wednesday in response to the BuzzFeed News report.

“The only person who bears responsibility here is Tom Malinowski for his decision to lobby against the creation of a national sex offender registry,” Chris Pack, the communications director for the committee, said in a statement, calling the congressman’s actions “disgusting.” “Congressman Malinowski must live with the consequences of his actions.”

Mr. Malinowski said he had confronted Representative Tom Emmer of Minnesota, the National Republican Congressional Committee’s chairman, on Tuesday evening on the House floor about the QAnon death threats inspired by his committee’s ads. Mr. Emmer, he said, denied knowing what QAnon was and said that he was not responsible for what others did with the committee’s campaign material.

The misleading information about voting by mail was not uniform. It broke down into six main categories, according to the analysis. In the month of September, they included:

• mentions of absentee voting or ballots, such as the false idea that it will be an unreliable way to vote: 410,918 mentions

• mentions of voter fraud, such as mentions of misleading stories about criminal conduct involving mail-in ballots: 345,040 mentions

• mentions of voter IDs, such as the baseless idea that in states with strict voter ID laws, mail-in ballots have been dumped out: 31,021 mentions

• mentions of foreign interference, such as inaccurately asserting that “foreign powers” are counterfeiting millions of votes: 11,857 mentions

• mentions of ballot “harvesting,” a loaded political term used by President Trump for ballot collection, a process that is legal in 26 states where someone other than a family member can drop off your absentee ballot for you: 10,562 mentions

• mentions of a “rigged election”: 10,140 mentions

Facebook, YouTube and Twitter have made combating false information about voting a priority, including highlighting accurate information on how to vote and how to register to vote. But the platforms have struggled to apply their election misinformation policies evenly, and many of the false posts are not removed unless the messages are explicit about causing imminent harm in the voting process.

The Facebook pages of the Democratic presidential nominee, Joseph R. Biden Jr., the news site The Hill and MSNBC got the No. 4, No. 5 and No. 6 slots, with a total share of 17 percent of the debate conversation on the social network.

Just outside the top 10 was CNN, at No. 12 with 1 percent of the conversation. The New York Times had the No. 33 slot, according to CrowdTangle.

The debate, moderated by Chris Wallace of Fox News, will be the first time that President Trump and Mr. Biden, the Democratic nominee, face off.

A spokesperson from Fox News said the claim was “entirely false, and any assertion otherwise is patently absurd.”

Asked whether it had access to the questions before the debate, a spokesman for the Biden campaign, Andrew Bates, said, “No.”

On Tuesday, right-wing sites also shared the false claim that Mr. Biden was being outfitted with a hidden earpiece before the debate.

The debate, of course, has not yet begun, and there is no evidence that Mr. Biden will be assisted by an earpiece once it does. (A member of Mr. Biden’s campaign staff called the rumor “completely absurd” during a call with reporters on Tuesday.) But the theory is being speculated about in right-wing media, including on Fox News, and it has been shared thousands of times on Facebook. It was also advanced by “Q,” the pseudonymous poster behind the QAnon conspiracy theory.

“Secret earpiece” rumors are nothing new. In fact, they’ve become something of a fixture during presidential debate cycles, and part of a baseless conspiracy theory that tends to rear its head every four years.

The first real earpiece conspiracy theory dates to 2000, when Rush Limbaugh, the right-wing radio host, accused then-candidate Al Gore of getting answers fed to him through an earpiece during a “Meet the Press” appearance. (A representative from the show confirmed to Slate that all guests wear earpieces in order to hear the audio tracks of news clips played during the show, but there is no evidence Mr. Gore was fed any answers.)

Four years later, during the 2004 presidential debates, rumors circulated among left-wing bloggers that George W. Bush was getting help from a surreptitiously placed earpiece.

“This theory goes a long ways toward explaining the president’s consistently odd speech patterns,” wrote the liberal blogger Joseph Cannon.

Commentators on the left speculated about a “bulge” in Mr. Bush’s jacket (above), which they imagined concealed a hidden receiver into which Karl Rove, the former president’s political adviser, was speaking. The Bush campaign tried to bat down the rumors, but they persisted, even though no solid evidence ever surfaced. A NASA scientist even got involved in analyzing images of Mr. Bush’s jacket during the debate, looking for clues about the mysterious bulge.

In 2008, rumors again circulated online that a candidate was being fed answers during a debate. Ann Althouse, a law professor and conservative blogger, wrote that close-up TV stills showed that Barack Obama “was wearing an earpiece” during a debate with John McCain. (Ms. Althouse later recanted her theory, saying it was probably just light reflecting off Mr. Obama’s ear.)

In 2016, the rumor appeared again, this time attached to Hillary Clinton, who was accused by right-wing websites of wearing a secret earpiece. (One such story, which appeared on the conspiracy theory website Infowars, was shared by Donald Trump Jr. and other pro-Trump influencers.)

The secret earpiece rumor is not exclusively an American phenomenon. Foreign politicians, including Emmanuel Macron of France, have also been baselessly accused of wearing earpieces during debates.

Accusing the opposing party’s candidate of wearing a secret earpiece is not a particularly sophisticated disinformation tactic, nor would it probably provide much help to a candidate even if it were true. (In fact, as anyone who has ever watched a live TV anchor fumble with a producer’s instructions could tell you, listening to directions in an earpiece while staying attentive to a moderator’s onstage questions requires a fairly impressive act of multitasking.)

But the idea of a hidden helper giving one side an unfair debate advantage has proved seductive to campaign operatives trying to explain away a lopsided debate, or sow doubts about cheating on the other side. As a 2016 Salon piece about the earpiece conspiracy theory said, these rumors mainly seem to appeal to hyperpartisans whose views on the candidates are already made up.

“When someone presents you with grainy screen captures of George W. Bush or Hillary Clinton and claims that they show telecommunications equipment hidden on their bodies,” the piece said, “your partisanship enables you to bridge the sizable gap between the poor evidence and the firm conclusion that someone offstage was whispering into the candidate’s ear.”

But new research suggests that the biggest jolt to QAnon came from the so-called “Save the Children” movement. It started out as a fund-raising campaign for a legitimate anti-trafficking charity, but was then hijacked by QAnon believers, who used the movement to spread false and exaggerated claims about a global child-trafficking conspiracy led by top Democrats and Hollywood elites. This hijacking began in July, around the same time that Twitter and Facebook began cracking down on QAnon accounts.

Marc-André Argentino, a doctoral student at Concordia University who studies QAnon, has been tracking the growth of “Save the Children” Facebook groups, many of which operate as soft fronts for the movement.

Mr. Argentino identified 114 groups that bill themselves as anti-trafficking concerns, but are actually dominated by QAnon content. Since July, he found, these groups have increased their membership by more than 3,000 percent — yes, 3,000 percent — with a corresponding surge in activity within these groups.

“Save the Children really revitalized the community after Twitter and Facebook took action against QAnon,” Mr. Argentino said. “It’s introduced an entire new population to QAnon.”

Mr. Argentino also found that traffic to several pieces of core QAnon content — such as “Fall of Cabal,” a YouTube video that many QAnon believers have credited with spurring their interest in the group — has surged in recent weeks, after months of decline.

Facebook, Twitter and other social networks have tried to limit the spread of QAnon, shutting down some accounts and pages associated with the movement. But “Save the Children” is a fuzzier area for platform enforcers, because it can be difficult to tell who is genuinely concerned about child exploitation and who is taking advantage of those concerns to sow misinformation. That vagueness has helped QAnon believers avoid a total crackdown, and has given them venues to discuss their theories that aren’t as vulnerable to being taken away.

Adopting “Save the Children” as a mantra helped save QAnon in several other ways. It created a kind of “QAnon Lite” on-ramp — an issue QAnon believers could talk about openly without scaring off potential recruits with bizarre claims about Hillary Clinton eating babies, and one that could pass nearly unnoticed in groups devoted to parenting, natural health and other nonpolitical topics.

Typical of the new, understated QAnon style are Facebook videos in which parents sound the alarm about pedophiles brainwashing and preying on children. These videos, wrote Annie Kelly, a researcher who wrote a Times op-ed about QAnon’s appeal to women this month, make for “compelling and dramatic content” that is “easily shared in other parenting groups with little indication of their far-right origins.”

Since stopping child exploitation is an issue that has broad and bipartisan sympathy, QAnon’s anti-trafficking rebranding has also allowed politicians to appeal to QAnon supporters without explicitly mentioning the theory. And seeding misinformation about child sex trafficking on platforms like Instagram and TikTok has allowed QAnon to tap into a younger and less explicitly pro-Trump demographic.

“It’s bringing down the average age of a QAnon follower,” Mr. Argentino said. “In 2019, this was mainly a boomer movement. Now we’re seeing millennials and Gen Z getting on board.”

Mr. Argentino’s research shows just how effective QAnon’s “Save the Children” pivot has been. In addition to spurring in-person rallies all over the world, the movement has become one of the most potent forces on Facebook. Stories about child exploitation and human trafficking routinely end up being among the most-shared news articles on the site, and some QAnon-adjacent scandals — such as the uproar over Netflix’s “Cuties” film, which was discussed for weeks inside QAnon Facebook groups before it was condemned by Republican lawmakers as promoting child sexualization — have crossed over into mainstream political discourse.

There is nothing wrong with expressing concerns about child exploitation, which is real and harmful. But QAnon’s embrace of the “Save the Children” movement has created its own harms. Legitimate anti-trafficking groups have reported being flooded with calls from QAnon believers passing on false and debunked tips, forcing the groups to divert resources away from their actual work. QAnon believers have organized virulent harassment campaigns against people they accuse of being pedophiles, including celebrities like Chrissy Teigen and Ellen DeGeneres.

And some QAnon followers have pursued acts of vigilante justice against the imagined “cabal” they believe is running an underground child sex-trafficking ring. Last year, a Colorado woman was arrested on suspicion of plotting with other QAnon supporters to have her son kidnapped from foster care. (The woman, Cynthia Abcug, has pleaded not guilty.)

As Mr. Argentino points out in a recent Twitter thread about his findings, there is some evidence that the growth of “Save the Children” may be slowing down. Sharing of posts inside the 114 groups he tracked has declined in recent weeks, even as membership in the groups has continued to rise. Facebook’s recent crackdowns may explain part of the falloff in sharing. But it could be evidence that QAnon — which needs a constant supply of fresh misinformation and new narratives to keep its community hooked — is preparing to move on.

“People are getting bored,” Mr. Argentino said. “There’s only so much content about child sex trafficking that you can share.”

County officials said they were not sure of the origin of the false report, but by Friday it had been picked up by some conservative media outlets on Twitter. Conservatives and President Trump have recently seized on news reports of issues with mail-in ballots, such as nine that were found to have been discarded in a northeastern Pennsylvania county.

Sonoma County’s post underscored the difficulties that local election officials face in combating misinformation in the final six weeks before the Nov. 3 election. With the local news media in crisis across the nation, fighting misinformation largely falls on area officials, who are already stretched thin to meet the demands of the most complex election in decades.

For officials on the front lines in Sonoma, correcting the record as quickly as possible was paramount.

“I think we wanted to be proactive and make sure that people got the information from us, because we did hear from some concerned citizens,” said Deva Marie Proto, the county registrar of voters in Sonoma County.