HIV-1, babies, and breast-feeding

Despite the fact that the radically religious and conservative politicians like to focus on homosexual males and IV drug use leading to HIV-1 infection, the fact of the matter is, heterosexual women are the fastest growing group of HIV-1 patients in the US (and Africa, and Asia)– even women in committed relationships (usually considered ‘low risk’).

It then naturally follows that if heterosexual women are getting infected, then the babies born to these women are also at risk of contracting HIV-1.

Unfortunately, this is the group of HIV-1 patients that I study.  Babies born to HIV-1 positive mothers, and are either infected in utero or during birth or breast-feeding.

A review just posted in Science covers pretty much everything there is to know about mother-to-child transmission:

HIV-1 Reservoirs in Breast Milk and Challenges to Elimination of Breast-Feeding Transmission of HIV-1

The good news is, giving Mom antiretrovirals before and right after birth is decreasing the number of babies infected in utero or during birth.

The bad news is, babies are still getting infected from breast feeding.

The good news is we have formula that can take the place of breast milk.

The bad news is breast milk is really, really, really good for Baby.

How can we get Baby breast milk, without getting Baby infected with HIV?

To answer this question, you first have to understand how, exactly, HIV-1 is getting transmitted.  To a layman, the ‘answer’ is obvious– there is virus in the breast milk, and that exposes the baby.  Get Mom on antiretrovirals, decrease her viral load, decrease the amount of free-virus in her breast milk, decrease Babys exposure.  But its not that simple.

Its not just free-virus found in breast milk– there are a whole host of immune cells from Mom… including T-cells… which can be infected with HIV-1 and spitting out not ‘a’ virus, but tons of virus.  Baby is eating HIV-1 factories.

And, because Babys stomach isnt yet fully acidified (which is why antibodies from Mom work in Baby), the infected T-cells can churn out virus, which can have a field day with the immune cells populating Babys digestive tract.

Well, why not give Baby antiretrovirals, then?  Just while they are breast feeding to prevent infection?

Because if Mom is on antiretrovirals, some of the drug gets into her breast milk.  Baby getting antiretrovials from Mom and getting their own dose of drugs is a recipe for an OD of medication.

There are so many details in this review, and I believe, at least for now, it is open to the public– If you are interested in this topic, I have really simplified things here, so read the original.  But the authors conclude the following:

Although cell-free HIV-1 particles can mediate HIV-1 transmission from breast milk to infant, especially late in lactation, cell-associated HIV-1—either latently infected or activated, virus-producing T cells—is predominantly responsible for breast milk–mediated HIV transmission.

This mechanism can explain the residual risk of HIV transmission to infants by mothers taking combined ARV therapies with no or minimal HIV-1 RNA in their body fluids. Indeed, the equation “no detectable HIV-1 RNA equals no transmission,” which correctly applies to sexual transmission and perinatal transmission of HIV-1, does not apply to breast-feeding transmission.

It is therefore unlikely that mother-to-child transmission of HIV-1 can be eliminated by maternal ART only. In contrast, infant preexposure prophylaxis, administered during the entire duration of breast-feeding, is more likely to protect exposed babies against all possible routes of breast milk transmission, including cell-to-cell viral transfer. To achieve optimal adherence during infant preexposure prophylaxis, long-acting drugs that can be more practically given to infants and that have a good safety profile are urgently needed.

If we figure out how to stop mother-to-child transmission, my research will be antiquated.  One of those things future scientists say is ‘Good science, but pointless because ‘no one gets infected with HIV that way anymore”.  I will be the happiest uncited author on the planet.

Comments

  1. #1 dustbubble
    the pub with no beer
    July 24, 2012

    Like you say, formula is one way of dodging the bullet. But as we all know, countries where The Virus is rampant tend to also be those places where clean water and ‘sterilising’ products (for the fairly sizeable amount of kit needed to do the botttle-fed thing properly) are very much a luxury. So it looks like we’re back to you boffins, and trusting you to nut out a way of fucking up the transmission.

    BTW very entertained by the big ad flashing away on the right of this post today.
    I have a prediction for Norah. Even I shall outlive thee, witch.

  2. #2 Bob Powers
    July 24, 2012

    As you pointed out, formula is not gonna transmit HIV.

    Unfortunately, we’ve already seen tragic results from pushing formula into super-poor areas of the world– the locals, being poor, too often dilute the formula to make it last until the next handout. Diluted formula means undernourished baby. Sometimes with severe deficiency issues… back in the early days of “scientific formula” the formula countries pushed their product strongly into these areas of the world, and we saw the results. Not good.

    But neither is HIV-infected baby.

    Catch-22?

  3. #3 Bob Powers
    July 24, 2012

    Ooops– spell-check– make that

    .. formula companies

    … not countries… meh

  4. #4 Charl
    July 25, 2012

    I know a chemical engineering student who designed a nipple shield that would deliver ARVs to the baby as it suckled. But it’s too expensive to commercialise in the parts of the world that need it most…

  5. #5 daedalus2u
    http://daedalus2u.blogspot.com/
    July 27, 2012

    What about a treatment that caused those HIV infected cells to undergo apoptosis?

    A treatment like nitric oxide?

    http://www.ncbi.nlm.nih.gov/pubmed/10666481

    Adults have commensal bacteria on the tongue that reduce nitrate in saliva to nitrite and in the low pH of the stomach the nitrite is reduced to NO which can reach ~100 ppm in the stomach head space (this is a gigantic level, enough to kill you if it oxidized to NO2 and you breathed it). Infants don’t develop these commensal bacteria on their tongue until about a year of age.

    There might be some ways of doing this that would be cheap enough.