False stories about Joe Biden’s health continued to spread on social platforms the day after the first presidential debate, including misleading Facebook ads by the Trump campaign and a viral video on TikTok.

A false story about Biden wearing an earpiece that emerged on Tuesday continued to get traction on Facebook after the debate. The Trump campaign ad, which encourages people to “Check Joe’s Ears,” and asked “Why won’t Sleepy Joe commit to an earpiece inspection,” was viewed between 200 to 250,000 times and marketed primarily to people over 55 in Texas and Florida. The implication of the ad, the content of which originated from a tweet by a New York Post reporter who cited a single anonymous source, is that Biden needed the assistance of an earpiece so someone could pass him information during the debates.

And on the video platform TikTok, four grainy videos alleging that Biden was wearing a wire to “cheat” during the debate racked up more than half a million combined views on Wednesday, according to research by the left-leaning media watchdog group Media Matters. One of the videos shows a still of Biden with his hand inside his suit, while another overlays an arrow over Biden’s tie, but neither video shows any visual evidence of Biden wearing an electronic device of any kind.

Tech companies have long struggled with misinformation and are on high-alert going into the election. Ahead of the debate, Twitter and Facebook executives reviewed hashtags, trends, and other accounts that may break the companies’ rules using a combination of software and human review. The companies are also pushing out accurate information about how to register to vote to millions of people.

But the latest evidence shows that they continue to struggle, particularly when it comes to falsehoods spread by the president and his followers.

On Wednesday night, Facebook said the falsehoods would undermine the legitimacy of the election, following the company’s previous announcement of a ban on new ads in the week before the election.

Adding to concerns, Twitter said it acted on a tip from the FBI to remove 130 accounts that appeared to originate in Iran and were attempting to sow disinformation during the presidential debate. Twitter said the accounts had a minimal reach.

TikTok said it would remove the Biden video after being contacted by The Washington Post. The company prohibits misinformation that “misleads community members about elections or other civic processes.”

The campaign ad on Facebook focusing on Biden reveals a significant hole in the social media giant’s enforcement efforts. Though the company says it spends a huge amount of resources combating election-related misinformation — including on fact-checking posts and news articles — the social network does not fact-check political ads as a matter of policy. That makes paid speech an exploitable category for misinformation. Hundreds of Facebook employees have opposed the company’s policy to not fact-check political ads.

Facebook spokesman Andy Stone declined to comment on the Trump campaign’s misleading ads that suggested Biden wore an earpiece. However, he did note that the company had taken other steps to limit misinformation about Biden wearing an earpiece, including adding labels to some posts to that effect from accounts that did not belong to politicians after its third-party fact-checkers debunked those claims.

Facebook did take the rare step on Wednesday of removing Trump ads that made baseless claims that accepting more refugees would increase health risks related to the pandemic. There were more than 30 versions of the ad running on the social network, according to Facebook’s ad transparency library. It had gathered between 200,000 and 250,000 impressions.

“We rejected these ads because we don’t allow claims that people’s physical safety, health, or survival is threatened by people on the basis of their national origin or immigration status,” Stone said in a statement.

Cat Zakrzewski contributed to this report.