Tanya is a spirited 22-year-old with dark, cropped hair, a penchant for body art, and a secret. On a chilly October afternoon, she sits at a round wooden table in a knitting shop in New York City and shows off her latest tattoo. Her companion, a 56-year-old nurse practitioner named Susan Ledlie, examines the design and grins, pulling up her sleeve to display her own.

Ledlie and Tanya (name changed) are an unlikely pair. Ledlie, a plump older white woman with a brisk maternal air, teaches graduate nursing at Molloy College in Long Island, New York, since retiring from her job as a nurse practitioner in 2010. Tanya, young and black with a cavalier attitude towards adulthood, grew up with her grandmother in Brooklyn, NY and wants to be a hairdresser. Yet the two have been close friends for 16 years. In 1995, when Tanya was six years old, her grandmother took her to Ledlie’s clinic in Brooklyn. Tanya had HIV. She had become infected at birth when she came in contact with her mother’s blood, and was diagnosed soon after.

“The first time I saw Susan, I remember I had to get my shots for school,” says Tanya. “I was kicking and pushing Susan and she had to bring three other doctors in to hold me down.” From that day forward, Ledlie saw Tanya at least once a month, as her primary Aids care provider - a role that included prescribing drugs, doing regular medical checkups and providing teenage counselling. “Visits became like a family thing,” Tanya laughs.

Ledlie’s role was almost unthinkable three decades ago. In June 1981, the US Centers for Disease Control and Prevention reported the first known case of what would eventually become known as Aids. Just a year later doctors began to diagnose the disease in children. Initially, they were treated with zidovudine - the first antiretroviral medicine designed to treat HIV - or nothing at all. During these early years of relevant ignorance about the disease, 45% of HIV-positive children died before their tenth birthdays. “We were focused on pain relief and comfort, without any thoughts about the child’s future,” says George Siberry, an adolescent HIV expert at the US National Institutes of Health.

But in the years since Tanya was diagnosed, there has been a dramatic shift in what it means to be born HIV-positive, particularly in western countries. Today, babies born to mothers infected with HIV receive anti-HIV medication within hours of birth and are not breast-fed so as to avoid passing the virus from mother to child. As a result, fewer than two babies in every 100 born to HIV-positive mothers in the US and Europe become infected with the virus. With treatment, 95% of kids now reach the age of 10. “Since antiretroviral therapy, we’ve showed they can live well into adulthood, although we don’t know for how long,” says Siberry.

This is Generation HIV. They are the first kids and young adults to have battled a lifelong infection since birth, and scientists are trying to understand what that really means. “There are so many unanswered questions,” says Yvonne Kingon, an HIV nurse practitioner in New York City who now treats Tanya. “Are these kids’ immune systems the same when they’ve been fighting a virus since birth? What does it mean to be an adult and have been on multiple medicines throughout your life?” she says.

A long-term study of 450 HIV-positive youth aims to answer some of those questions. The Pediatric HIV/AIDS Cohort Study (pHAcs) began in 2005 and now has 21 sites across the United States. Researchers are studying two groups of adolescents: those infected with HIV at, or shortly after, birth, and those who were exposed to treatments as infants or during foetal. They hope to understand the effects of the long-term use of HIV medications and the impact of HIV on the biology and psychology of these children. Infectious disease specialists have been closely watching these young survivors, analysing their cellular makeup and immune health, and characterising the HIV virus in the context of these patients’ infections. The study will also collect information on immune function, neurological development, cardiac function, bone growth and metabolism. Siberry says the early results show some worrying results, such as increased risk of heart attacks, attention deficit and language learning abilities, as well as higher rates of asthma. “But we won’t know for sure until we’ve followed this pioneering group into their 30’s, 40’s and 50’s,” he says.

‘Dangerous secret’

According to the United Nations, at the end of 2010, there were 3.4 million children (under 15 years of age) living with HIV around the world – nine out of 10 living in sub-Saharan Africa. Every hour, around 30 children die as a result of Aids, but in the developed world, paediatric HIV has morphed into adolescent HIV, and brought with it a fresh set of obstacles. When Ledlie started as a paediatric HIV nurse practitioner in 1991, most kids who came to her clinic died by age three or four. “They stopped crawling and holding their bottles…they became stiff as a board until they died,” she says. But a couple of years into her practice, she reached the first landmark in her fledgling career. “The first kid whose kindergarten graduation I could go to, that was a big thing,” she says. “It was like, ‘wow’.”

Today, instead of fending off swift, deadly infections, practitioners - and HIV-infected youth - are grappling with subtle complications. Two danger areas, according to HIV researchers, are cardiovascular health and neurological illness. Early results from the pHAcs study and others show that many of the children who have been treated with anti-HIV medications since a young age have heart abnormalities, higher cholesterol levels, and above-normal rates of obesity and glucose intolerance—a precursor to diabetes. “In the long run, these factors put the kids at higher risk of heart attacks and strokes,” says Siberry. But scientists emphasise that these results don’t necessarily herald an epidemic of cardiovascular disease among HIV-positive youth over the next decades. They are initial findings and more work needs to be done to understand what factors contribute to the risk. “It just means we are mindful of the risk and exploring the use of new medications that don’t increase cardiovascular side-effects,” says Paul Krogstad, a physician and virologist at the University of California, Los Angeles.

These kids also have higher than normal rates of mental health issues including depression, substance abuse, attention deficit disorder and learning difficulties. We don’t yet know the effect of HIV on the brain during development,” says Krogstad. It’s still unclear whether the cause is social - a consequence of the kids’ socioeconomic backgrounds and speckled family history - or biological. “It deserves close scrutiny,” he says.

Whilst questions like this will take time to answer, there are more immediate challenges facing Generation HIV.

Sex can be a messy issue for many young adults, but when an adolescent is HIV positive, it is even more complex. Unlike their peers, these teens have to think about public disclosure of their HIV status, the impact of their sexual encounters on their partners, and whether they want to have kids of their own. “I kinda grew up with this disease and it’s totally different now,” says Ledlie. Pediatric Aids specialists are wading into unfamiliar territory when they begin talking about pregnancy with their patients. Because of the inextricable relationship between sexuality and HIV transmission, some small studies in the UK and the US have followed the pregnancies of young, HIV-positive women, to assess their reproductive and sexual health, and found their fertility remains relatively intact. One study did however find that a high proportion of girls had abnormal cervical cells, although this could be attributed to their increased susceptibility to genital infections like the human papilloma virus, a cause of cervical cancer.

Tanya’s long-term boyfriend still doesn’t know she is HIV positive. “It’s hard to tell a person whom you’re already so [physically] close with,” she says. Tanya says she always insists on using protection, but sometimes her boyfriend asks if it’s because she “has something.” “My excuse is that I don’t want to get pregnant,” says Tanya. But she has had a pregnancy scare. “Susan sat me down and she was like, ‘How do you wanna do this?’” says Tanya. Although Ledlie tried to convince Tanya to tell her boyfriend, she has refused to reveal her secret.

Regime change

Clearly, there are still huge challenges and unknowns. But studies of Generation HIV have also thrown up glimmers of hope. For years, physicians worried that children infected with the virus would grow up with crippled immune systems. But, research shows that most of the children have suppressed the infection and have nearly normal levels of the CD4+ immune cells that are typically destroyed by early HIV infection. That’s good news.

Yet not everything is quite as it should be. Many of the group received their childhood vaccinations before they were put on HIV medications but after their immune systems had been compromised. This has made them more susceptible to certain viral diseases, such as shingles and its complications, as well as bacterial infections that can cause pneumonia and meningitis. “Their immune systems were not in optimal shape to make a lasting protective response. That’s something fairly unique about this group,” says Siberry. “We need to do something different to protect them against vaccine-preventable illnesses.” Some ideas about how to tackle this problem include starting anti-retroviral therapy in infancy, before they are given their childhood vaccines, to preserve immunity to vaccine-preventable diseases. An alternative could be to re-vaccinate young children once they’ve been on the therapy for a few years.

Another hot-button issue for this unique cohort is that of drug resistance. Kingon, who inherited Ledlie’s cases in 2010 when she retired, finds her biggest challenge is getting her patients to adhere to their drug regimes. “Adolescents are always going to do what they want to do. If you order them around, they’ll either get fed up and leave or they’ll ‘yes’ you to death,” says Kingon. When adolescents become lax about their treatment, it can have serious medical repercussions. Skipping HIV meds gives the virus an opportunity to start multiplying rapidly again and to develop drug resistance.

The daily medications have always been Tanya’s biggest challenge. Taking your life-saving medication may seem like a straightforward and obvious thing to do for someone in her position, but taking “meds” is not just a simple case of popping a pill once a day. There are more than 20 different drugs approved for the treatment of HIV in the US and Europe. Many patients take a combination of drugs, often two or three at a time, to reduce the likelihood of developing resistance and make treatment more effective. In the past, HIV-positive people used to take as many as 30 pills a day. Although things have improved so that many of the drugs are combined into a single pill, some patients may still need to swallow a tablet two or four times a day. Even after her mother died of Aids and substance abuse in 2004, Tanya didn’t stick to her regime, says Ledlie. Together, Ledlie and Tanya worked on a week-to-week schedule. “I would call her and ask her to do good just for a week,” says Ledlie.

Although Ledlie is not Tanya’s physician anymore, she can’t seem to shake that role. “Have you been taking your meds?” she asks casually. Tanya shakes her head, but insists that she knows she should. “I know you know,” Ledlie says, holding Tanya’s gaze for an extra beat. Tanya says she realises the dangers of drug resistance and is ready to change her attitude - particularly if she wants to have kids someday. “I hear Susan’s voice in my head all the time when I walk past my meds on my dresser,” she says. “I’m getting older and I want to change before it’s too late.”

The need for holistic medical care like Ledlie’s is becoming obsolete in the west. The sick helpless babies who have survived HIV infection are now independent grown-ups who need to transition safely into adult HIV healthcare. “These children - I still call them that, though they aren’t - they really are the pioneers,” says Siberry. He says it’s important for the medical community to stay in touch with this generation to see how their bodies and minds respond to the virus and the medications through adulthood. “For their sakes, but also for younger children who will be following them in future decades.”

If you would like to comment on this story or anything else you have seen on Future, head over to our Facebook page or message us on Twitter.

Latest Stories

What is the future of sex?

In Depth

Sex

Sex

In Depth

In Depth

'I have never felt sexual desire'

In Depth

Best of 2015

Best of the Web

Video

TED Quotes

In Depth

In Depth

Neurohacks

Around the bbc