Posted by 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:
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.
July 24, 2012
July 25, 2012
