Canadian scientists involved in research into treating infants within days or even hours of birth

Treating HIV infection hours to days after birth could improve a person's chances of having a long and healthy life, researchers say.

Two studies released this week, ahead of World AIDS Day, focus on improving long-term health outcomes, in children or adults, by treating HIV sooner.

"Early is better" may seem self-evident. But HIV doctors and scientists say that wasn't the case when powerful but toxic treatments first became available. Now, treatments are safer than they were decades ago.

"Initially, we waited until people actually had symptoms from their HIV, but now we know that if we actually start treating earlier, the overall damage to the immune system will not be as much," says Dr. Laura Sauvé, a pediatric infectious disease specialist at BC Children's Hospital in Vancouver.

Sauvé said adults who get infected with HIV, the virus that causes AIDS, might not have any symptoms for years, so it might seem "counterintuitive" to treat someone before they feel sick.

She said a study released this week by researchers at Harvard University in Boston, treating infants with HIV early in Botswana, is important because it showed how treating sooner:

Improves health.
Affects how a baby's immune system evolves.
Shrinks HIV's reservoir, an important step toward understanding how to cure HIV infection
The reservoir is a place where HIV hides out and sleeps. When someone is treated with antiretrovirals, the virus becomes undetectable in the blood but it still lurks hidden in the central nervous system and other immune cells, said Sauvé, who was not involved in the study.

"The smaller the reservoir, the better the chance that we have of us eventually getting rid of HIV in the body."

For the study in Botswana, researchers treated 10 infants born with HIV within hours to a few days after birth.

After two years, the 10 children treated the earliest had a smaller reservoir of HIV and more robust functioning of a key part of the immune system, compared with a second group of 10 infected infants who started treatment months after birth.

Without treatment, 50 per cent of HIV-infected children die by two years of age, Dr. Roger Shapiro of the Harvard T.H. Chan School of Public Health told reporters in a teleconference hosted by the journal Science Translational Medicine.

In sub-Saharan Africa, it's estimated 300-500 pediatric HIV infections occur each day, Shapiro said.

2nd study

While early treatment shows promise, prevention remains paramount, Sauvé said. Treating pregnant women with antiretrovirals prevents the virus from spreading to the baby.

In Canada, about 245 babies are born to women living with HIV each year, and about 98 per cent of the mothers have access to treatment. Still, one to five new HIV-infected babies are born every year across the country, Sauvé said.

Meanwhile, Sauvé said, a Canadian counterpart to the Botswana trial called EPIC4 also aims to study whether early treatment of infants born with HIV is effective.

Both trials began after the birth in 2010 of the "Mississippi baby," a girl who received a combination of three antiviral medications within 30 hours of her birth. Even though her family stopped treatment when she was a toddler, her HIV stayed in remission for 27 months before it relapsed and she restarted treatment.

A second HIV study published this week in the journal Cell Reports focused on preventing HIV at an even earlier stage.

Using a humanized mouse model, virologist Éric Cohen and his team looked at whether the virus can be attacked during the brief window of time between when it enters the body and when it spreads beyond the area of infection.

"As soon as you stop treatment, the virus rebounds," said Cohen, a professor of microbiology, immunology and infectious disease at the University of Montreal. "The virus rebounds because it is hidden … and silent in these cells that establish very early on."

To prevent infection, scientists need to understand the early stages of HIV infection, when the virus is most vulnerable, Cohen said.

Since HIV doesn't harm regular mice, Cohen's experiment used mice with immune systems that were replaced by human immune systems susceptible to HIV.

Overwhelm HIV early

Our immune system has an innate component that kicks in immediately to recognize foreign patterns in viruses and bacteria to help prevent or control infections.

"They found this specific cell that's involved in the innate immune system that, if you treat it with a specific type of drug, you can enhance its function, and by doing so it provides better immune response and more protection," said Eric Arts, a professor of microbiology and immunology at Western University in London, Ont., who wasn't involved in Cohen's study.

These cells, called plasmacytoid dendritic cells, are small, rounded cells that patrol the body, on guard to detect invaders as part of innate immunity, and alerting other defences.

But in HIV infection, these guard cells are lost, allowing infection, and disease, to progress.

The big caveat, Arts said, is that the research is at a mouse model stage — a long way from a vaccine that's safe and effective to use in humans.

Tricky HIV

And the complexity of HIV has stymied vaccine researchers for decades.

"Each time researchers have thought they were onto a strategy that might protect people, HIV is tricky enough to get around those strategies," Sauvé said.

As Canadians mark World AIDS Day on Sunday, it's a chance to take stock of progress toward the World Health Organization's and UNAIDS' goal of 95-95-95 by 2030:

Identify 95 per cent of those infected.
Treat nearly all of them.
Make sure they're successfully virus-suppressed enough that it doesn't harm their health and won't be sexually transmitted to someone else.
Arts, who hold the Canada Research Chair in HIV research, said Canada isn't there yet.

Despite the 95-95-95 goals, in 2016, an estimated 86 per cent in Canada were diagnosed and aware they had HIV (meaning 14 per cent didn't know); 81 per cent of those who were diagnosed were on treatment; and 89 per cent of those on treatment had achieved viral suppression, according to CATIE, a Canadian HIV awareness and research organization.

"Unless we reach those goals of higher levels of knowing people are infected, treated and sustained treatment — effective treatment — we're never going to be successful."

 

 

By: Amina Zafar
Source: https://www.cbc.ca/news/health/hiv-second-opinion-1.5379058