HIV baby boom: Following perinatally-infected children
HIV baby boom: Following perinatally-infected children
How is their disease different in adulthood?
HIV clinicians and investigators now have a unique opportunity to learn more about the disease as the last large group of U.S. babies infected with HIV at birth are approaching adulthood with prospects of living decades longer.
The discovery in the early 1990s that administering antiretrovirals to pregnant women prior to delivery and to their infants for six months after birth could have a big impact on reducing mother-to-child (MTC) HIV transmission rates was one of the major medical breakthroughs in the HIV research, says Rohan Hazra, MD, medical officer for pediatric, adolescent and maternal AIDS branch of the Center for Research for Mothers and Children at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health (NIH) in Bethesda, MD.
"At that point it became feasible to think about eradicating pediatric HIV," Hazra says.
This discovery quickly was followed by highly-active antiretroviral therapy (HAART), which meant children infected with HIV, as well as infected adults, could live nearly normal lives for far longer than ever believed possible during the early years of the AIDS epidemic.
In the United States, the number of newly infected babies is miniscule, he adds.
Also, the annual mortality rate from HIV among children in the United States has plummeted from five to 10% to less than 1%, Hazra says.
"The mortality rate keeps diminishing because these children survive into adulthood," he says. "We have about 10,000 perinatally-infected children in this country, and it's a population that now is marching into adulthood."
These are the first wave of perinatally-infected children who soon will be adults, but they will be followed by millions of children worldwide as antiretroviral therapy has become more widely available.
"We're trying to put some spotlight on this population," Hazra says. "Now that these children have survived they have a lot of issues related to psychosocial and medical care."
From peds to adult care
The children will now have to transition from the pediatric-centered medical care system to the adult HIV care system, he notes.
"They're used to being in a pediatric care system where there's a lot of time spent on them, and it's very inclusive, involving family members," Hazra explains. "On the adult-side there's less hand-holding, and you're seen as an adult and are expected to take care of yourself."
It's important that U.S. researchers follow the perinatally-infected children as they transition to adulthood to gather information that could prove very useful in coming decades, Hazra says.
"We're trying to learn lessons that might help with planning around the world as millions of children around the world gain the benefits of antiretrovirals," he says.
"From a research standpoint, we're trying to capture transition between models of care," Hazra says. "We think this is an extremely important population to follow."
Hazra and other investigators have begun enrolling HIV-infected children in the Pediatric HIV/AIDS Cohort Study (PHACS), which will look at long-term outcomes related to the children's bone health, liver and kidney disease, cardiac disease, and cognitive functions.
"One area that needs a lot of research involves what's going on in their brains," Hazra says. "In the absence of antiretroviral therapy, HIV gets in the brain very early in children."
For HIV-infected infants, the physical manifestations are very different from adults, he notes.
Adults who progress to AIDS might develop dementia very late in the disease, with about 10% of HIV-infected adults developing dementia if untreated, Hazra says.
"In infants, the disease we used to see a lot of is encephalopathy, which developed early on in the first year to 1.5 years of life and was seen in up to 40 to 50% of untreated infants," Hazra says.
"So that manifestation of HIV has almost disappeared in this country," he says. "With antiretroviral therapy you almost never see devastating encephalopathy."
There are occasional cases where children didn't adhere to therapy, he adds.
But another cognitive issue has arisen with HIV-infected youth.
"As these youths age we're seeing high rates of certain conditions, like a lot of attention deficit disorder, depression, and other psychiatric abnormalities," Hazra says. "There are cognitive impairments, trouble with learning, reading, and processing speed and with what psychologists call executive function — how well you organize your life."
Since these children being studied are all perinatally-infected, their disease cannot be seen in isolation. The children might all have one or more parents who also are HIV-infected, and most of them are minorities who come from economically-disadvantaged backgrounds, he adds.
"So when we say there are high rates of attention deficit disorder, we mean it's higher than the general population," Hazra explains. "But is it really higher than peers from the same environment, who are not HIV infected?"
So PHACS investigators also are enrolling an uninfected peer group.
There will be 450 perinatally-infected youth, ages seven to 16 years, at 15 centers and 227 uninfected youth at the same centers, which are located in the United States and Puerto Rico.
"These are the kinds of studies we're going to be doing, looking at their neurological status and evolution," Hazra explains. "We have this group we can compare it to and tease out how much is HIV infection and how much is other aspects of the environment and host genetics, as well."
The impact of ART
Investigators also are very interested in the impact of HIV and ART on the perinatally-infected children's bone health and their cardiovascular risk factors.
"The 29-year-old with perinatal infection has had the disease for 29 years and has the risk of whatever metabolic disease you have with HIV and ART," Hazra says.
Another interesting lead investigators will follow involves the children (5% of the cohort) who were not on ART and did not meet the criteria for needing ART, despite having been infected perinatally.
"There's a small, distinct percentage of youth who were able to come off ART and stay off ART," Hazra says. "We identified that group, and now we're looking at how we can design more careful studies to see if there are things we can tease out of that population to predict how we can do better, whether we can find ways to control the virus."
The PHACS cohort includes youth who were infected before HAART was available, so they've survived despite suboptimal therapy early on, Hazra notes.
"Once the combination therapies became available, they were difficult to take and were not child friendly," he says. "So adherence has been quite difficult in the pediatric population."
Plus children entering their teen-age years go through all of the emotional struggles common with adolescents, and these also make it difficult to adhere to their medication, he adds.
"So these youth are special; they're survivors," Hazra says.
If there can be a way to halt ART without negatively impacting the children's health, then it would be worth pursuing, he says.
"It'd be nice to give some youths a break when they're struggling with other issues in their lives," Hazra adds.
HIV clinicians and investigators now have a unique opportunity to learn more about the disease as the last large group of U.S. babies infected with HIV at birth are approaching adulthood with prospects of living decades longer.Subscribe Now for Access
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