Four HIV-infected children treated right after birth show no detectable virus but its resurgence in a fifth who stopped medication means it's too soon to talk of a "cure," say Canadian researchers.
Their findings were presented Saturday in St. John's, N.L., at a conference hosted by the Canadian Association for HIV Research.
"I think it's a step in the right direction," said Dr. Ari Bitnun, an infectious disease specialist at Toronto's Hospital for Sick Children.
"It adds support to the Mississippi case," he said, referring to a child known as the Mississippi Baby who U.S. doctors suggest was "functionally cured" of HIV.
"It may be that it will work for some babies and it won't work for others."
Bitnun is part of a team of specialists examining whether early treatment of at-risk infants in the first hours of life means better outcomes than drug regimes started later.
The scientists from the Hospital for Sick Children, Montreal's Ste-Justine Hospital and the Children's Hospital of Eastern Ontario have received almost $2 million from the Canadian Institutes of Health Research, the International AIDS Society and the Canadian Foundation for AIDS Research.
Their results have not yet been published in a peer-reviewed medical journal.
It was big news in March 2013 when U.S. doctors raised the prospect of a pediatric cure relating to the so-called Mississippi Baby. It involved an infant born prematurely in rural Mississippi in the fall of 2010 to a woman who had not seen a doctor during pregnancy and was unaware she had HIV.
The infant was about 30 hours old when two blood tests indicated a low level of the virus. The child was immediately given a three-drug regimen as treatment _ not the one- or two-drug preventive dose usually given in the U.S. at that stage.
The baby, whose gender was not disclosed, is now 3 1/2 years old and seems to be virus-free two years after being taken off HIV drugs.
In Canada, it has been long-standing practice to begin early treatment of infants born to mothers whose HIV was not well controlled. There are typically fewer than 10 known cases a year, said microbiologist Hugo Soudeyns, another researcher on the Canadian study.
Bitnun said in an interview that findings presented Saturday involve five children treated with a combination of antiretroviral drugs within 24 hours of birth. Four of those kids, now aged between three and eight, show no detectable virus in repeated blood tests, he said.
But a key difference between those children and the Mississippi Baby is that they were not taken off HIV drugs, Bitnun said.
The fifth child, partly due to difficulty administering regular doses, was removed from medication at about age three. That child had previously shown small levels of the virus-even while on treatment-and it soon rebounded, Bitnun said.
"It's very important to emphasize that this is a long way from calling these kids cured," Bitnun said of the four who remain on their drug regime.
Still, there are exciting indications that seem to support the Mississippi Baby findings, he added.
"When you start treatment very early in a baby that's infected you can probably reduce the amount of virus in their blood or in their body as a whole significantly."
Bitnun stressed that preventing infant infection by treating HIV-positive women during pregnancy is the Canadian standard of care and is always preferable.
"We can essentially guarantee that the babies won't be infected, period."
Lack of medical attention in developing countries, however, means about 260,000 children around the globe became newly infected with HIV in 2012, according to United Nations estimates.
But it isn't clear how a new treatment protocol after birth would help in parts of the world where access to good care isn't available, said Dr. Mark Wainberg of McGill University, a leading AIDS researcher with a peripheral role in the study.
"The possibility of testing for HIV is almost non-existent in many cases,'' he said in an interview. ``It's going to be very tough to find a way to make these findings applicable in a manner that we'd fully like in a developing country setting."
Wainberg stressed his support for more research toward a possible pediatric cure. But he noted that before AIDS drugs were available, just one in four children born to HIV-infected women ultimately developed the virus.
He questions whether HIV circulating at birth necessarily means it would thrive long-term.
"How sure are we, really, that these babies truly had actually infected cells in their body?"
Soudeyns said blood from the five infants studied underwent "state-of-the-art" tests.
"There's in my mind no question that HIV infection had taken hold."