AUDIE CORNISH, HOST:
There's news today of a toddler who may be the first child to be cured of infection with the AIDS virus. The case involves a 2 1/2-year-old girl in Mississippi. Scientists are hearing more about the case today at a conference in Atlanta. Only one other case of an HIV cure has ever been documented. That was in a 47-year-old San Francisco man. Joining me to talk about this surprising development is NPR health and science correspondent Richard Knox. And, Richard, to start, tell me about this surprising cure. How did it come about?
RICHARD KNOX, BYLINE: Well, it's what scientists call a natural experiment. That means nobody planned it. This little girl was born to a mother somewhere in Mississippi, in mid-2010, and the mother had had no prenatal care and didn't know that she, in fact, was infected with HIV. A routine test showed that she was. And at that point, the doctors realized this little baby was at very high risk of being infected herself, transferred her immediately to University of Mississippi in Jackson. And there, an infectious disease specialist named Hannah Gay realized that the baby was at very high risk of infection.
She put the baby on three antiviral drugs at higher than usual dosages beginning only 31 hours after birth. Later, the infection was confirmed and treatment caused the blood levels of this - of the virus in this baby to go down, which is what normally happens.
CORNISH: And then I understand the mother actually stopped taking the child to the clinic.
KNOX: Yes, that's right, Audie. At 18 months of age, the little baby and the mother disappeared from the doctor's radar screen. They didn't know where they were. When they finally tracked them down last August, they expected to find lots of virus in this baby's blood because that's what happens when infected kids go off treatment. They found, to their astonishment, that they couldn't find any virus. And later, ultrasensitive tests couldn't find any evidence either. And the girl has been off treatment for a year now.
CORNISH: So what was different about this child? I mean, millions of newborns have gotten HIV over the past 30 years. Many of them have gotten treatment.
KNOX: That's right. Two big things that were different this time. First of all, the earlier and more aggressive treatment than children who were exposed and infected at birth usually gather - almost ever get, and then secondly, this child had her treatment stopped. That would never be done deliberately, or at least it wouldn't be up to now or up to that time because it would be unethical to do that.
CORNISH: Now, has there any been skepticism? I mean, first of all, about whether this child was really infected at all?
KNOX: Yeah. And the skepticism is totally understandable. This is one case. Researchers will want to follow this little girl closely to see if the virus comes back. They want to look at the evidence very closely. But from what we know at this point, it does seem likely that the infection was real.
Four leading labs around the country using the most sophisticated tests can't find any evidence that the virus is still in her blood. A couple of tests have found pieces of the virus, short strands of DNA and RNA, but no sign the virus is capable of multiplying.
CORNISH: And this is only one child. We've also heard of an adult that's been cured. Where do things stand with that story?
KNOX: Well, there's a 47-year-old man in San Francisco named Timothy Brown who was cured after he got a bone marrow transplant for leukemia that basically gave him a new immune system from a donor who was resistant to the virus. But that's not going to be repeated very often, if at all. Nobody believes that this new child cure will change the way how HIV is treated in adults.
Curing adults who have established infection is much more complicated because the virus has gotten a foothold. It's hiding out in millions of immune cells. It's very difficult to eradicate when it gets to that step.
CORNISH: Still, I can imagine that if this case holds up, it could have pretty significant impact on the developing world, for instance.
KNOX: That's, I think, the main excitement now. And it suggests - this case in Mississippi suggests that it's possible to cure HIV infection in infants using drugs that are readily available and cheap. It doesn't mean that it will be easy to do that within a day or two of birth. But researchers think that it will be doable and that at the will be available to do it because the stakes are so high. It could give thousands of children a lifetime free of antiviral drugs. But it's going to take two or three years to show that this one case was not a fluke and to show how to do it consistently in the real world.
CORNISH: That's NPR's health and science correspondent Richard Knox. Richard, thank you.
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