Facebook users have been bombarded with misleading ads about medication meant to prevent the transmission of HIV, according to lesbian, gay, bisexual and transgender advocates, who say the tech giant’s refusal to remove the content has created a public-health crisis.

The ads have been viewed millions of times in recent months, Facebook’s archive reveals, and LGBT organizations argue they’ve had a dire effect: They’ve scared patients, potentially those who may be most at risk of contracting HIV, out of taking preventative drugs, known as PrEP, even though health officials and federal regulators have said they are safe.

Many of the ads appear to have been purchased by personal-injury lawyers and entities affiliated with them. They allege in lawsuits that HIV medications, such as Truvada, actually threaten patients with serious side effects. But groups led by GLAAD, which regularly advises Facebook on LGBT issues, say the ads are “false” and have urged Facebook for months to take them down — to no avail.

In response, GLAAD plans to step up its efforts on Monday, joining the Human Rights Campaign, The Trevor Project and 49 other prominent LGBT groups in publicly calling out the tech giant for a policy that puts “real people’s lives in imminent danger.”

The ads also have worried some health professionals, like Demetre Daskalakis, the deputy commissioner for the Division of Disease Control at the New York City Department of Health and Mental Hygiene. He said the ads, which he has seen on his own Facebook feed, threaten to undo years of work to promote a drug that can cut down on the transmission of HIV and potentially save lives.

“I still see patients,” Daskalakis said. “Four of my seven PrEP patients came in and said, ‘How could you be putting me on this medication that’s so unsafe? My Instagram ads say so.’”

Facebook, meanwhile, says the ads do not violate its policies.

“We value our work with LGBTQ groups and constantly seek their input,” spokeswoman Devon Kearns said in a statement. “While these ads do not violate our ad policies nor have they been rated false by third-party fact-checkers, we’re always examining ways to improve and help these key groups better understand how we apply our policies."

For Facebook, the dispute surrounding its approach to Truvada and other HIV medications reflects its continuing struggle over what to do about false, ambiguous or controversial ads in the age of the Internet, where social-media platforms easily can become conduits for misinformation — with unprecedented influence and reach far beyond its print, radio and television predecessors.

The issue has commanded rare public attention recently because of the 2020 election, given the falsehoods peddled by President Trump’s campaign that Facebook has refused to take down. But political ads next year are expected to generate less than 1 percent of the company’s revenue, reflecting the enormity and complexity of Facebook’s task — as a site that serves more than 2 billion users globally — to protect people from a wide array of harm.

Determining what is true and false often is difficult, and the content the company allows or rejects can have vast consequences for free speech, civic discourse and even public health. Personal-injury lawyers representing thousands of HIV patients, for example, say the data actually are on their side — and that they have a role in informing patients about the risks in medication.

“These Facebook ads provide a service to let them know there are options available for them now,” said Robert Jenner, the co-lead counsel in the consolidated lawsuit.

For paid speech that isn’t purchased by candidates, Facebook’s fact-checkers do vet some dubious claims, and the company takes action against ads that could harm users in real life. Facebook also has specific policies around ads that touch on sensitive health issues such as vaccines. The social-networking giant began clamping down on anti-vaccine groups this February after months of criticism that it had allowed malicious actors to spread falsehoods about such preventative care.

For LGBT activists, the concern is that Facebook has become a conduit for false or misleading information about HIV prevention medication. They pointed to ads run by Facebook pages under names such as "Lawsuit Watch" and "Advocate Alliance Group" in October that encouraged people who may have "suffered kidney or bone damage after Truvada/PrEP" to reach out for possible "financial compensation."

“Almost immediately we started hearing reports from front-line PrEP prescribers, clinics and public health officials around the country, saying we’re beginning to hear from potential clients that they’re scared of trying Truvada because they’re seeing all these ads on their Facebook and Instagram feeds,” said Peter Staley, a long-time AIDS activist who works with the PrEP4All Collaboration. “We realized we had a major problem on our hands.”

To LGBT groups, the trouble with ads about Truvada is a critical distinction involving the way the drug is administered. It can be taken as a form of treatment by those who have HIV, and it can be taken as a form of prevention by those who do not.

When taken as HIV treatment, the drug — and others that share a key ingredient, a form of the antiretroviral tenofovir — may cause serious side-effects, potentially in combination with some other medications. Some patients have brought lawsuits in response, alleging that manufacturers, such as Gilead, caused people undue harm by keeping better, less harmful drugs off the market for years. When taken as HIV prevention, however, PrEP is considered safe and not life threatening, according to experts, including the Centers for Disease Control and Prevention, which says that “no serious side effects have been observed.” Lawyers in pending litigation contest this claim.

Some of the Facebook ads unearthed by LGBT leaders lack nuance, they say. The ads attribute serious kidney and bone side-effects to PrEP, which activists argue is incorrect. And they use images of pills that might lead a person to think they’re taking something dangerous for them, even though the research says otherwise, said Daskalakis, a top health official in New York City.

Adding to activists and experts’ fears, it is unclear how personal-injury lawyers and other advertisers are targeting their ads. Facebook does not disclose what characteristic, such as one’s personal interests or traits, determines if people see an ad. Instead, its public ad archive reveals only general characteristics and the number, in ranges, of people who ultimately viewed it.

The six ads purchased in October by Lawsuit Watch and Advocate Alliance Group, for example, had as many as 1.3 million views on Facebook, a Post analysis of Facebook records shows. That reflects only a small fraction of the total PrEP-related ads that have given activists pause. Contacted over Facebook, the operators of those pages did not respond to a request for comment.

Another page called “A Case For Women,” which appears to connect potential plaintiffs with law firms, ran a series of five ads in August and September that said “Truvada and other HIV prevention medications have been linked to serious bone and kidney problems,” according to Facebook’s archive. The series of ads had been viewed up to 500,000 times, company records show.

The leader of the organization, Susan Jones Knape, initially said in an email to The Post that her group was “not running Facebook ads related to Truvada.” Presented with an example, she clarified that her group had run ads for six weeks.

Jenner, the personal-injury lawyer helping to lead the litigation, described ads about Truvada and PrEP as essential and appropriate. “The claim that somehow this is dangerous to a certain group of people who have HIV, but is not dangerous to people who do not have HIV, is misplaced,” he said.

LGBT groups first took action in September, reaching out to contacts at Facebook in a bid to get the problematic PrEP ads removed. GLAAD, in particular, sought to leverage its position in Facebook’s “Network of Support,” a collection of six organizations that long have formally guided the tech giant’s work on LGBT issues. After weeks of silence, Facebook referred GLAAD to its “public-facing page that lists Facebook ad policies” and its third-party fact-checking process, said Rich Ferraro, GLAAD’s communications officer.

Since then, GLAAD has contacted Facebook’s independent fact-checkers, including the Associated Press, but has received only a short response from the AP acknowledging it had received the note. Since then, no labels have been appended to any of the ads. Facebook declined to explain to The Post how the ads fit with their policies, and the AP did not respond to a request for comment.

“Facebook’s refusal to take action on ads that target at-risk community members with false medical information points to a much larger problem for Facebook users and an urgent need for LGBTQ safety to be prioritized across their products,” said Sarah Kate Ellis, the leader of GLAAD.

With the ads still active — six months after initially discovering them — GLAAD and its peers are publicly sounding the alarm. In a new open letter to Zuckerberg, they pointed to the Facebook executive’s own, prior statements on Capitol Hill. Responding to a question from Rep. Alexandria Ocasio-Cortez (D-N.Y.), Zuckerberg pledged at a congressional hearing that the company in cases of “imminent physical harm” would always “take that content down.”

The 52 LGBT organizations say Facebook has failed to live up to Zuckerberg’s pledge. “By allowing these advertisements to persist on their platforms, Facebook and Instagram are convincing at-risk individuals to avoid PrEP, invariably leading to avoidable HIV infections,” they wrote. “You are harming public health.”

To be sure, some LGBT advocates said that Facebook — the place many people turn for information — isn’t wrong to allow lawyers to reach out to users about serious health issues. And they didn’t take issue with some of the claims levied as part of patients’ lawsuits.

Instead, they said the problem is the language and photos that some lawyers have used in their ads, and Facebook’s refusal to engage with them on improving policies that directly affect patient care, which have out-matched their ability to inform people at scale on the social network.

"Facebook, when we confronted them with all this, acted like the god-like institution they are," said Staley, the long-time AIDS activist, lamenting the company’s slow response.

“They refused to budge even though we said that’s not how it played out in the real world,” he continued, adding of Facebook’s behavior: “You’re feeding the crisis.”