Tue March 5, 2013
What A Mississippi Baby Can Tell HIV Researchers
Originally published on Mon March 18, 2013 1:53 pm
ARI SHAPIRO, HOST:
Now this week, doctors announced a breakthrough in HIV research. A Mississippi toddler who was born with the virus appears to have been cured. Doctors credit an aggressive regimen of anti-retroviral drugs administered just after the girl was born. This is the second well-documented case of someone being cured. The other involved a middle-aged San Francisco man who received a bone marrow transplant from a donor who was genetically resistant to HIV.
So if you have questions about the case of the cured Mississippi baby, we're here to answer them. Call us at 1-800-989-8255. Our email address is email@example.com, and you can join the conversation at our website. Go to npr.org and click on TALK OF THE NATION. Our guest is NPR science and health correspondent Richard Knox, with us from Dorchester, Massachusetts. Thanks for joining us, Dick.
RICHARD KNOX, BYLINE: Sure, Ari.
SHAPIRO: OK. So a baby was born with HIV, as so many babies are around the world nowadays. What happened next?
KNOX: The baby was born about mid-2010, somewhere in Mississippi, don't know where, about 100 miles from Jackson, and the mother had not had any prenatal care. When she was tested herself for HIV, which would be routine in this kind of situation, the doctors found that she was positive. And so they realized that her baby was at very high risk of having the virus herself. And so they transferred that baby fortunately very quickly to the University of Mississippi in Jackson.
And there, an infectious disease specialist named Hannah Gray recognized that this was a very high-risk baby, and so she decided to go beyond the usual protocol for these kinds of situations and give this child, within about 31 hours of birth, a regimen of three antiviral drugs that attack HIV and...
[POST-BROADCAST CORRECTION: The infectious disease specialist is named Dr. Hannah Gay.]
SHAPIRO: And higher than normal doses of them, right?
KNOX: Yes. The normal dose in this situation would be called a prophylactic dose, which means to prevent infection.
KNOX: But Dr. Gay decided that, you know, to assume that this baby was infected - she didn't know at the time - and so presumably, you know, an infected child would be given a therapeutic dose, not a prophylactic dose. And then it turns out subsequently that the baby was shown to be infected. Five different tests over the next months show that it was a true infection, which is an important point because skeptics and, you know, AIDS researchers around the globe want to be sure that this child was really infected in the first place because otherwise obviously you couldn't know if it was a cure.
And so things were going along well. The - within about a month, the baby had no detectable HIV in her blood, which is normal. That's what you'd expect under treatment. And then about 18 months of age for this baby, the mother stopped bringing her into clinic, and the doctors didn't know where the mother or the baby were. And that's a critical thing. Obviously...
SHAPIRO: So treatment could not continue?
KNOX: They didn't know whether treatment was continuing or not...
KNOX: ...until they found the mother and baby again last August through the assistance of the child protective and health people in Mississippi. And at that time, the mother said - who apparently was having a lot of chaotic changes in her life, according to Dr. Gay. The mother said that she had stopped giving the HIV drugs to this baby six or seven months before. And so Dr. Gay thought, well, there must be - the virus must have come back because that's what always happens when you stop treatment.
SHAPIRO: Sure. When you stop taking the drugs for six months, yeah.
KNOX: Yeah. So she did the test to determine what she should begin treating the child with again, because the danger was that the virus might have become resistant, and so she shouldn't necessarily use the same drugs that she used before. And so she was really astonished to find that they could not find any virus in this baby. She contacted a close friend here in - up here in Massachusetts, where I'm based, Dr. Katherine Luzuriaga - who's been studying infants and teens with HIV for years - and said, you know, what do I - help me. And so Dr. Luzuriaga's lab and others in San Diego, in Bethesda, in Baltimore did the most sophisticated test on this child's cells.
SHAPIRO: And they all concluded that the HIV was just gone.
KNOX: Couldn't find it.
SHAPIRO: So I understand there's still some skepticism, though, from the scientific community. Tell us what the critique is.
KNOX: Yes. Well, I think skepticism is appropriate, because it's been - although it's been a year since this baby was - stopped treatment and the virus hasn't been returned according to these sophisticated tests, you know, they need to follow on, beyond this. And also, it's only one child.
KNOX: And so this is going to be watched very closely while studies are being designed to see if it can be repeated.
SHAPIRO: Mm-hmm. Although the circumstances of this sound so unusual, it's almost an incredible coincidence that it even took place in this one instance.
KNOX: Yes. Scientists call this a natural experiment, which just means that nobody planned it this way. It just happened. And you can't - you can't ethically do that, at this point...
KNOX: ...namely stop treating someone.
SHAPIRO: Stop treating someone for HIV and see whether the disease comes back or not. Let's take a call from Andrew in Denver. Hi, Andrew. Go ahead.
ANDREW: Hi. Thanks for taking my call.
ANDREW: I just wanted to know what this means for viral - anti-viral research in general. Does this give us any window into potential cures for other viral diseases? And I'll take my answer off the air.
SHAPIRO: OK. Dick Knox.
KNOX: That's a good question. I think - nobody I've talked to so far has speculated about what it might mean beyond HIV. There's a lot of speculation about what it might mean for treating HIV in other children, in poor countries and wherever, and also what it might mean for research into doing something about infected adults. And we might want to come back to that. It may have application to other so-called retroviruses. This is a particular kind of virus that HIV and hepatitis C and other viruses are, but I don't really know what they would be at this point.
SHAPIRO: Well, let's talk about the applications to adults. There was another case of a full-grown man who received a bone marrow transplant for leukemia from somebody who had a resistance to HIV, and he appeared to have been cured, as well. Talk about the similarities and differences between these two cases and what we can learn from them.
KNOX: Yes. He's the famous Berlin patient, Timothy Ray Brown, who now lives in San Francisco, but got a bone marrow transplant about - in 2007 in Berlin, and still has no evidence of the virus - of actively replicating virus in his system and is well. There have been a couple of other patients here in Boston who've been treated with a bone marrow transplant and who don't have any virus in their blood. The important difference is that they're still getting anti-viral drugs, as far as we know. The big problem is - and I think that the Mississippi baby's case really does underscore this, is that if you can get - with adults, you usually cannot find somebody in time to treat them within 31 hours of exposure.
SHAPIRO: Of infection, yeah.
KNOX: I mean, sometimes, you do know when the exposure occurred. And we all - you know, doctors already give something called post-exposure prophylaxis, which are drugs given in a hope of preventing HIV infection.
SHAPIRO: If you think you've been exposed.
KNOX: Right. But that's, you know, that's obviously a very small proportion of people out there.
KNOX: And therefore, once the virus gets established and multiplies, probably within weeks, and hides out in what are called resting T-cells - these are immune cells where the virus gets inside and stays there for a lifetime, presumably - then it's very difficult to cure those patients. It's being tried, and there's some ingenious experiments, some of them being reported this week at this meeting in Atlanta, where this Mississippi case was described. But so far, you know, nobody knows whether that's going to be possible.
SHAPIRO: So, Dick, walk me through, if there are examples of adults taking a prophylactic dose of anti-HIV drugs, if they've, say, been pricked by a needle or had unprotected sex and not been infected, you know, infection has been prevented by the prophylactic dose. How is that different from this baby who, shortly after being born, was given more or less the same sort of treatment?
KNOX: Well, the main hypothesis about the Mississippi baby and how she didn't have - apparently has been cured, is that they caught the virus so soon after she was infected - presumably she was infected before birth, but, you know, within hours of birth - that the virus didn't have time to establish these reservoirs, they're called, these hideouts in the body. And that's a critical thing about the timing of this treatment, as well as the higher doses. With adults, you don't, you know, you can't do that.
SHAPIRO: Yeah. Let's take another call from Robert in Cape Coral, Florida. Hi, Robert. Go ahead.
ROBERT: Hello, there. I just wondered if the measure of being cured was a zero viral load, because if that's the case, I know several people who've gone to a zero viral load from treatment with, like, high-dosage intravenous vitamin C. Of course, we're not going to see any studies showing that, because there's no money in vitamin C.
ROBERT: But - go ahead.
SHAPIRO: Dick Knox, is a zero viral load the measure of being cured for this baby?
KNOX: No, not just that. But let - first of all, let me just define for people out who don't think about viral loads very often. A viral load means the amount of virus that's detectable in the blood, and that's certainly one key measure that - and there is no detectable virus in the blood of this baby. But there isn't detectable virus in the blood of many people on treatment. That doesn't mean that they don't have virus in their system that's capable of springing to life and being - and multiplying wildly once the treatment is stopped. But they did go way beyond that. In four or five different labs around the country, they did very, you know, cutting-edge, sophisticated, ultra-sensitive tests to determine whether this virus was hiding out somewhere in the child's cells. And they couldn't find any evidence of it.
SHAPIRO: So, Dick, as you've described, you can't exactly replicate this study, because it's not ethical to give a baby anti-HIV treatment and then take that treatment away to see whether the virus comes back. If it's not replicable, where do you go from here?
KNOX: Well, it may be ethical at some point, and they're going to have to try to work that through. There are studies being designed right now on the basis of this case to try to diagnose and treat very early, as this baby was treated, with triple drugs at therapeutic doses - most likely in African countries, where 330,000 babies are born every year to HIV-infected moms. There are only something like 130 such cases in the United States, thankfully, because U.S. pregnant women are usually identified and treated before birth.
So they'd like to try to treat the same way high-risk babies in other countries, while they try to figure out whether there are some markers in the blood or cells of these babies that would indicate when it might be safe to interrupt therapy. Now, it's important to say, you know, if you do interrupt therapy and the virus came back, then you could reinstitute therapy. So it's not - you know, it's - there may be ethical ways of doing this. But they have to be really, really sure that they have a scientific basis for interrupting treatment before they do.
SHAPIRO: That's NPR science and health correspondent Richard Knox, joining us to talk about a fascinating breakthrough on HIV research with a baby in Mississippi who appears to have been cured. Thanks for joining us, Dick.
KNOX: Any time.
SHAPIRO: And you're listening to TALK OF THE NATION, from NPR News. Transcript provided by NPR, Copyright NPR.