It has been nearly four decades since the first AIDS cases were reported in the U.S., but stigma against HIV-positive people persists, especially among younger Americans who were not alive during the early — and darkest — days of the epidemic.

A survey released Monday found that more than a quarter (28 percent) of HIV-negative millennials have avoided hugging, talking to or being friends with someone with the virus. Thirty percent said they’d prefer not to interact socially at all with people who have HIV.

Sponsored by Merck and the Prevention Access Campaign, the report also found that 23 percent of HIV-negative millennials — and 41 percent of HIV-negative Gen Z respondents — admitted they were either “not at all” informed or “only somewhat” informed about HIV. Nearly half of the HIV-negative respondents, who were all 18 to 36, said they believed the virus could be transmitted by someone whose viral load was undetectable. (It can't.)

HIV can only be contracted by coming into direct contact with certain body fluids, like blood and semen, from a person with HIV who has a detectable viral load, according to the U.S. Department of Health and Human Services.

Chris, a 32-year-old consultant, said living in big cities has not shielded him from discrimination due to his HIV status.

“I went to a dentist in Atlanta, and after filling out the medical history form I overheard one of the nurses saying they wouldn’t touch me — even with gloves on,” he told NBC News. “Needless to say, I left after having a harsh word with the dentist.”

Chris said he can go months with only positive experiences, only to have one bad encounter remind him that ignorance persists.

“Things that you would expect to hear 20, 30 years ago are still alive and well,” he added. “No, you can’t get HIV from sharing a toothbrush or a toilet seat — or from a hug.”

Those uninformed attitudes don’t just impact HIV-positive people’s mental and emotional well-being: They can lead them to avoid treatment, according to health professionals.

“Stigma absolutely plays a role in noncompliance,” Dr. Sohail Rana, professor of pediatrics at the Howard University College of Medicine, told NBC News. “People get into a relationship, and they don’t want anyone to know they’re taking medication. I had a patient tell me, ‘My baby doesn’t get their morning [medications] because I don’t want the babysitter to find out.”

Dr. Sohail Rana is a professor of pediatrics at the Howard University College of Medicine. Courtesy of Howard University

Rana, the organizer of Howard’s annual International Conference on Stigma, said the Merck survey might actually understate the situation.

“Doctors, research institutes, medical organizations — they spend pennies on stigma. They spend it all on drugs,” Rana said. “But we can change minds with social marketing — we got Americans to hate smoking! We can teach compassion and understanding. We need messages on TV and social media to combat stigma from doctors, researchers, activists and people with HIV."

In 1988, Surgeon General C. Everett Koop’s pamphlets got vital information about HIV to 107 million American households. But a new generation has come of age in the decades since, and education efforts haven’t kept pace.

The findings released Monday were based on an online survey of 1,596 millennials (ages 23 to 36) and Generation Z (ages 18 to 22) Americans, half of whom were HIV-positive.

The results, according to Prevention Access Campaign's executive director, Bruce Richman, are a wake-up call that the AIDS crisis is far from over.

“Despite scientific advances and decades of HIV advocacy and education ... young adults overwhelmingly are not being informed effectively about the basics of HIV,” Richman said in a statement. “It’s time to elevate a real conversation about HIV and sexual health among America’s young people, and roll out innovative and engaging initiatives to educate and fight HIV stigma.”

The report is pegged to a new educational campaign, “Owning HIV: Young Adults and the Fight Ahead,” aimed at guiding perceptions about HIV among young Americans, who account for the majority of new diagnoses.

“Understanding the problem is the first step in preventing a deepening of the HIV epidemic,” Dr. Peter Sklar, director of clinical research at Merck Research Laboratories, said. Sklar, who has been treating people with HIV/AIDS since the 1990s, said learning of the disconnect between clinical realities and people’s attitudes was “game-changing.”

“We must continue to search for ways to better understand young people’s perceptions of HIV, promote safer sex behaviors and drive education and action in this population,” he explained.

Wanona "Nunu" Thomas is an HIV-positive mother of four. She was diagnosed three years ago, while she was pregnant. Elizabeth Brooks

Wanona "Nunu" Thomas, an HIV-positive mother of four, was diagnosed three years ago while she was pregnant. As a young, black, heterosexual woman, she said she’s part of a community “that is often lacking knowledge and not given a face in this fight.” In fact, the study found one in three Latinx and African American respondents reported avoiding shaking hands or sharing food, drinks or utensils with someone living with HIV.

At a recent family gathering, Thomas recalled, a close family friend ate a piece of her sandwich and used her utensils. When the friend’s partner found out, she took their children and left.

“She felt he was putting his children at risk,” Thomas said. “As a mother ... to find out I was the cause of someone’s children being stripped away from them really hurts — but more than that it angers me, because you’d imagine that, here in 2019, people would know casual contact can’t spread the virus.”

“I believe that the stigma of HIV is what’s killing people,” Thomas added, “not the disease itself."

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