Since then, false and misleading information about Ms. Harris has spiked online and on TV. The activity has jumped from two dozen mentions per hour during a recent week to over 3,200 per hour in the last few days, according to the media insights company Zignal Labs, which analyzed global television broadcasts and social media.
Much of that rise is fueled by fervent supporters of President Trump and adherents of the extremist conspiracy movement QAnon, as well as by the far left, according to a New York Times analysis of the most widespread falsehoods about Ms. Harris. On Thursday, Mr. Trump himself encouraged one of the most persistent falsehoods, a racist conspiracy theory that Ms. Harris is not eligible for the vice presidency or presidency because her parents were immigrants.
“Sadly, this wave of misinformation was predictable and inevitable,” said Melissa Ryan, chief executive of Card Strategies, a consulting firm that researches disinformation.
Many of the narratives are inaccurate accusations that first surged last year during Ms. Harris’s campaign to become the Democratic presidential nominee. Here are three false rumors about Ms. Harris that continue circulating widely online.
The ‘PizzaGate’ Conspiracy Theory
On Wednesday, a day after Mr. Biden announced his selection, the falsehood that Ms. Harris is connected to a child-trafficking conspiracy known as PizzaGate was published on the conspiracy-mongering website Infowars, which set off a round of sharing on social media.
PizzaGate hinges on the baseless notion that Hillary Clinton and Democratic elites ran a child sex-trafficking ring through a Washington pizza restaurant. According to the rumors about Ms. Harris, she is tied to the conspiracy because her sister was invited by John Podesta, Ms. Clinton’s presidential campaign manager, to a “Hillary pizza party” in 2016.
By Friday morning, more than 4,200 tweets discussed the unfounded theory about Ms. Harris’s connection to PizzaGate, according to Dataminr, a social media monitoring service.
On Facebook, users in dozens of QAnon groups and pages posted about the rumor. The falsehood reached up to 624,000 people, according to The Times’s analysis. On Instagram, which Facebook owns, 77 more posts tried to spread the lie further.
And on YouTube, a QAnon channel with over 100,000 followers pushed the conspiracy, too. “Remember, we know what pizza was code language for,” Daniel Lee, a YouTube personality popular in conspiracy circles, told his audience. The video was viewed 30,000 times.
A Facebook spokeswoman, Liz Bourgeois, said in an email on Friday that “it’s up to our fact-checking partners to determine which claims they rate, and they take a number of factors into consideration.” She acknowledged that as of Friday afternoon, there were no fact-checks so far on the widely shared posts falsely tying Ms. Harris to PizzaGate.
Twitter said on Friday that it permanently suspended people associated with QAnon who used many different accounts or tried to evade a previous suspension.
“We deploy a number of tools to add context to and address misinformation,” including applying labels, not recommending tweets and limiting the reach of tweets, a Twitter spokesman, Trenton Kennedy, said.
YouTube said Friday that it was reducing the spread of borderline content on the video site, including QAnon content, but that the video flagged by The Times did not violate its guidelines.
Falsehoods about Ms. Harris’s heritage — in particular that she is “not Black” — were among the most widely spread misinformation that Zignal Labs tracked. Since Tuesday, the argument had been mentioned over 40,000 times, the company found.
“Kamala Harris is not an American Black,” said one tweet that collected 2,300 likes and shares after it was first posted on Wednesday. “She is half Indian and half Jamaican. She is robbing American Blacks of their history. Kamala is as Black American as Obama.”
In a Facebook post on Tuesday night, Candace Owens, a right-wing commentator, posted a widely shared post questioning Ms. Harris’s heritage. “I am SO EXCITED that we get to watch Kamala Harris, who swore into congress as an ‘Indian-American,’ now play the ‘I’m a black a woman’ card all the way until November,” she wrote.
Facebook soon added a fact check to Ms. Owens’s post, requiring users to click past a label noting that third-party fact checkers found “this information has no basis in fact.”
Ms. Harris, the daughter of Jamaican and Indian immigrants, was born in 1964 in Oakland, Calif., a few years after her parents arrived in the United States. According to The Associated Press, Ms. Harris has long identified as Black; she was not sworn into Congress identifying only as Indian-American. In interviews, Ms. Harris has regularly spoken about how her mother, who was from India, raised her as Black.
Ms. Owens said in an email on Friday: “It is absurd to censor a truth followed by a future guess. This is why I am already in legal proceedings with Facebook fact-checkers. They have now begun censoring statements that were never said.”
Other memes on Facebook labeling Ms. Harris as “Kamala Dolezal” were liked and shared thousands of times, according to the Times analysis. The posts referred to Rachel Dolezal, a former official at the National Association for the Advancement of Colored People who was later revealed to be white and was charged in 2018 with welfare fraud.
Whitney Phillips, an assistant professor at Syracuse University who teaches digital ethics, said she was “absolutely not surprised” by the viral misinformation questioning Ms. Harris’s heritage.
“Regardless of political party, sexism and racism have long been fixtures in American public life,” Ms. Phillips said.
One of the most convoluted lies that has spread on social media involves the actor Jussie Smollett and the baseless allegation that Ms. Harris is his aunt and knew in advance that Mr. Smollett was planning to stage an assault against himself early last year.
According to the unsubstantiated narrative, when the Chicago Police Department and the F.B.I. investigated the alleged assault, Ms. Harris appeared in Mr. Smollett’s phone records, so she must have been in on the hoax.
The right-wing website True Pundit published an article pushing this argument in November. The article gained new prominence on social media this week, shared nearly 2,000 times on Twitter and reaching 180,000 people, according to CrowdTangle, a tool to analyze interactions across social networks.
A February 2019 article on FactCheck.org concluded that there was no relation between Ms. Harris and Mr. Smollett, and that evidence of her role in the hoax was nonexistent.
Ms. Harris did initially condemn the news of the apparent attack on Mr. Smollett, but when the police said the assault had been staged, she put out a new statement saying she was “sad, frustrated and disappointed” by the development.
Sheera Frenkel contributed reporting. Ben Decker contributed research.